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Zoological Journal of the Linnean Society, 2012, 165, 420–469. With 14 figures
Species limits within the Praomys delectorum group
(Rodentia: Muridae: Murinae) of East Africa:
a morphometric reassessment and
biogeographical implications
MICHAEL D. CARLETON1* and WILLIAM T. STANLEY2
1
Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution,
Washington, DC 20560-0108, USA
2
Department of Zoology, Division of Mammals, The Field Museum of Natural History, Chicago, IL
60605, USA
Received 18 October 2011; revised 23 December 2011; accepted for publication 31 December 2011
We examined approximately 600 specimens that represent the Praomys delectorum species group (Muridae:
Murinae: Praomyini), a rodent complex restricted to Afromontane landscapes in East Africa and currently viewed
as a single species. Morphometric analyses of 21 population samples consistently disclosed cohesive patterns of
craniodental differentiation that support the recognition of three species: Praomys delectorum Thomas, confined to
extreme southern Malawi; P. melanotus Allen & Loveridge, found in highlands of south-western Tanzania and
contiguous northern Malawi; and P. taitae Heller (including octomastis Hatt), distributed in mountains and
foothills of southern Kenya and northern and central Tanzania. Populations of the P. delectorum group are patchily
distributed in moist montane forest, most collecting localities falling within 1000–2400 m, and their range
collectively coincides with the Tanganyika–Nyasa Montane Forest Group sensu Moreau. Patterns of faunal
similarity derived from distributions of 65 species of terrestrial small mammals recorded from Tanzania’s
highlands, including the Eastern Arc Mountains, demonstrated pronounced geographical discontinuities in
montane associations but failed to uncover a prominent vicariant role for the Makambako Gap.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469.
doi: 10.1111/j.1096-3642.2012.00817.x
ADDITIONAL KEYWORDS: Eastern Arc Mountains – Makambako Gap – Praomys melanotus – Praomys
taitae – taxonomy.
INTRODUCTION
The genus Praomys (Muridae: Murinae) circumscribes a small radiation of rodents indigenous to
sub-Saharan Africa (Lecompte et al., 2002b) and
numbers from 16 to 22 valid species according to
recent workers (e.g. Musser & Carleton, 2005; Van
der Straeten, 2008). Species have been conventionally
divided among four morphologically well-defined
groups: the P. delectorum, P. jacksoni, P. lukolelae,
and P. tullbergi species groups (Van der Straeten &
*Corresponding author. E-mail: [email protected]
420
Dieterlen, 1987; Van der Straeten & Dudu, 1990; Van
der Straeten, 2008). Musser & Carleton (2005) recognized a fifth species group, the P. daltoni group, based
on molecular studies (e.g. Lecompte et al., 2002b).
Thanks to recent contributions by many investigators, knowledge of species limits and relationships
has been substantially improved for the P. jacksoni
and P. tullbergi complexes, the two most speciose and
broadly distributed of the five species groups, principally for member taxa that occupy lowland tropical
forest of West and Central Africa (Nicolas et al., 2005,
2008, 2010; Akpatou et al., 2007; Van der Straeten,
2008; Kennis et al., 2011). The alpha-level taxonomy
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
of the three smaller species groups, P. daltoni (two
species), P. delectorum (one species) and P. lukolelae
(two species), has drawn little attention over this
same period. This study addresses the P. delectorum
group.
Populations of Praomys delectorum inhabit humid
montane forests of south-eastern Africa, discontinuously occurring in isolated mountains and hills in
south-western Kenya, across central Tanzania, to
extreme north-eastern Zambia and southern Malawi.
As currently recognized (e.g. Musser & Carleton,
2005), four taxa are assigned to the nominal species
(Fig. 1): the senior epithet delectorum Thomas (1910),
described from the Mulanje Plateau, southern
Malawi; taitae Heller (1912), named from the Taita
Hills, southern Kenya; melanotus G. M. Allen & Loveridge (1933), named from the Poroto Mountains,
west-central Tanzania; and octomastis Hatt (1940),
described from forested highlands south of the Ngorongoro Crater, north-central Tanzania.
The taxonomic status and distributional extent of
delectorum and associated taxa have been clouded
since their description because of their synonymy
with other African small murines, in particular with
forms of Praomys, whether recognized as a genus (e.g.
Allen, 1939) or subgenus of Rattus (e.g. Ellerman,
1941). Although delectorum and taitae were both
named as species (Thomas, 1910, and Heller, 1912,
respectively), the forms melanotus and octomastis
were created as subspecies of P. tullbergi or P. jacksoni (Allen & Loveridge, 1933, and Hatt, 1940, respectively). By the time of Allen’s (1939) watershed
catalogue, A Checklist of African Mammals, the
status of P. jacksoni and P. tullbergi as morphologically distinct species was well established. Thereafter,
delectorum and melanotus, and later octomastis, were
commonly arranged as subspecies of P. jacksoni
(Allen, 1939; Swynnerton & Hayman, 1951; Lawrence
& Loveridge, 1953; Hanney, 1965); only Ellerman
(1941) persisted in listing delectorum and melanotus,
along with jacksoni, as subspecies of Rattus
(Praomys) tullbergi. Since the diagnosis of taitae,
however, many authorities continued to treat it as a
species of indeterminate range (Hollister, 1919; Allen,
1939; Ellerman, 1941; Swynnerton & Hayman, 1951).
In a short but influential paper, Davis (1965) reasserted the specific distinctiveness of delectorum and
provisionally assigned melanotus, octomastis, and
taitae as synonyms. Davis’s action established the
classificatory precedent to separate delectorum from
P. jacksoni, an arrangement observed in most subsequent taxonomic works (Misonne, 1974; Corbet &
Hill, 1980, 1986, 1991; Honacki, Kinman & Koeppl,
1982; Ansell & Dowsett, 1988; Musser & Carleton,
1993). Curiously, Misonne (1974) retained melanotus,
octomastis, and taitae as synonyms of unspecified
421
rank within P. jacksoni while recognizing P. delectorum as a monotypic species. More recently, Van der
Straeten & Kerbis Peterhans (1999) and Van der
Straeten (2008) have listed all four taxa as species.
Musser & Carleton (2005) followed Davis’s (1965)
interpretation – the single species P. delectorum with
three junior synonyms – pending presentation of supportive data and elucidation of distributions.
Our intent here is to reconcile these disparate
nomenclatural decisions by appeal to data, in particular morphometric evaluation of craniodental differentiation. The geographical samples necessary to
critically resolve the status and distributions of forms
assigned to the P. delectorum complex have materialized only recently, the evidentiary dividend of concerted biological inventory of Tanzania’s Eastern Arc
Mountains (Goodman et al., 1995; Stanley, Goodman
& Hutterer, 1996; Stanley, Goodman & Kihaule,
1998a; Stanley et al., 1998b, 2000; Stanley &
Goodman, 2011). Such fresh collecting efforts have not
only refined patterns of endemism within the Eastern
Arc Mountains (Stanley & Olson, 2005) but also
uncovered new species of small mammals (Stanley &
Hutterer, 2000; Carleton & Stanley, 2005; Stanley,
Rogers & Hutterer, 2005c). A secondary goal of our
study is to consolidate patterns of faunal affinity
among small mammals within the Eastern Arc Mountains, particularly with regard to the Makambako
Gap and assessment of its significance as a faunal
barrier.
MATERIAL AND METHODS
The 582 specimens reported herein consist principally
of skins with their associated skulls and are contained in the following museum collections: American
Museum of Natural History, New York City (AMNH);
The Natural History Museum, London (BMNH, formerly British Museum of Natural History); Carnegie
Museum of Natural History, Pittsburgh (CM); Field
Museum of Natural History, Chicago (FMNH);
Museum of Comparative Zoology, Harvard University
(MCZ); and the National Museum of Natural History,
Smithsonian Institution, Washington, DC (USNM,
formerly U.S. National Museum). M.D.C. examined
and measured the type specimens of melanotus Allen
& Loveridge (1933), octomastis Hatt (1940), and taitae
Heller (1912). The holotype of delectorum Thomas
(1910) was measured by Paula D. Jenkins (BMNH),
who also supplied digital photographs of its cranium
and mandible.
Throughout the text, figures, and specimens examined, we customarily abbreviate Mount (Mt) and
Mountains (Mts) where they form part of the proper
placename. We collectively refer to those Tanzanian
mountains north-east of the Makambako Gap and
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
422
M. D. CARLETON and W. T. STANLEY
Figure 1. Mountainous regions of East Africa inhabited by populations of the Praomys delectorum complex, covering an
area approximately 2–17°S by 30–41°E. Type localities are illustrated for the four species-group taxa currently assigned
to Praomys delectorum: delectorum Thomas, 1910 (Malawi, Mulanje Plateau, 1675 m); melanotus Allen & Loveridge, 1933
(Tanzania, Poroto Mountains, Nyamwanga, 1950 m); octomastis Hatt, 1940 (Tanzania, Old Mbulu Reserve, 1829 m); taitae
Heller, 1912 (Kenya, Taita Hills, Mount Mbololo, 1524 m). The Eastern Arc Mountains (sensu Wasser & Lovett 1993) are
those disconnected ranges in Tanzania and southern Kenya that trend in a north-eastern direction from the Makambako
Gap, including the Udzungwa Mountains through the Taita Hills.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
trending in a north-easterly direction from the
Udzungwa Mts to the Taita Hills as the Eastern Arc
Mountains (i.e. sensu Wasser & Lovett, 1993), hereafter abbreviated EAM. Following De Jong &
Congdon (1993), we identify the highland mass to the
west of the Makambako Gap and north of Lake
Malawi as the Southern Highlands (i.e. Mt Rungwe,
Livingstone Mts, and Poroto Mts); further, those outlying volcanic peaks to the north of the EAM are
informally categorized as the Northern Highlands
(i.e. Mt Kilimanjaro, Mt Meru, Mbulu Highlands, and
Ngorongoro Crater Highlands). The occurrence of
moist montane forest in south-eastern Africa (see
Fig. 10) was compiled from the World Wildlife Fund
Ecoregions, a digital resource available through the
USGS Global GIS Database: Digital Atlas of Africa
(version 5.9, October 2001). The upper- and lowercase abbreviations M1–3 or m1–3 are used to individually reference the upper (maxillary) and lower
(dentary) molars, respectively; individual cusps of the
upper and lower molars are referenced using the
positional t-system as developed by Miller (1912) and
refined by Musser & Newcomb (1983).
Fifteen cranial and three dental variables were
measured by M.D.C. to 0.01 mm, using hand-held
digital calipers while viewing crania under a stereomicroscope. These measurements, their anatomical
landmarks, and their abbreviations as used in text
and tables, are: occipitonasal length (ONL), from the
supraoccipital, just above the foramen magnum, to
the nasal tips; greatest zygomatic breadth (ZB), as
measured across the squamosal portion of the zygomatic arches or at the squamosal–jugal suture;
breadth of braincase (BBC), measured across the
parietal flanges just behind the zygomatic arches;
depth of braincase (DBC), from the basioccipital–
basisphenoid junction to the mid-saggital suture of
the parietals at their dorsalmost arch; breadth across
occipital condyles (BOC), at the upper lateral edges of
the articular processes of the exoccipital bones; interorbital breadth (IOB), a least breadth measured at
the lateral edges of the frontals; length of rostrum
(LR), from the innermost bevel of the right zygomatic
notch to the end of the nasals at their midsagittal
junction (i.e. measurement is slightly oblique to the
longitudinal cranial axis); breadth of rostrum (BR), as
measured across the capsular projections in front of
the zygomatic plates; postpalatal length (PPL), from
the anterior rim of the mesopterygoid fossa to the
midnotch of the basiocciptal; length of bony palate
(LBP), from the anterior margin of the mesopterygoid
fossa to the posterior end of the left incisive foramen;
breadth of bony palate (BBP), as measured across the
maxillary bones above the second molars; length of
incisive foramen (LIF), the maximum anterior–
posterior expanse of the left foramen; length of
423
diastema (LD), from the posterior curvature of the left
incisor, just below the premaxillary, to the enamel–
dentine junction (gum line) on anterior margin of the
left M1; breadth of zygomatic plate (BZP), from the
rear edge of the right zygomatic plate to its anterodorsal margin where it is vertical; length of auditory
bulla (LAB), from the posteriormost bevel of left auditory bulla to the anteromedial notch of eustachian
tube (i.e. where opaque bone of the eustachian tube
meets translucent bone of the tympanic capsule);
coronal length of maxillary toothrow (CLM), as measured on the right molar row, from the posterior
margin of M3 to the enamel–dentine junction on
anterior face of M1 (not on the forward sloping anterior root); width of the upper first molar (WM1), a
greatest width measured across the middle lamina
(t4–t6) of the upper right M1; depth of the upper
incisor (DI), from the inner curvature of the upper
right incisor (just above the sharpening bezel) to its
outer curvature. Five external dimensions (to nearest
whole mm) and body mass (to nearest 0.5 g) were
transcribed from skin tags or field catalogues as given
by the collector: total length (TOTL); head and body
length (HBL); tail length (TL); hindfoot length (HFL);
ear (pinna) length (EL); and weight (WT). External
data for most samples from Malawi and Tanzania
were recorded in the field by W.T.S., reducing amongcollector variability for these big, extremely agesensitive, dimensions. The series from the Taita Hills,
Kenya, was collected early in the 20th century, and
specimens lack field-obtained values for head-andbody length and weight; the former datum was
obtained by subtraction of TL from TOTL. Recording
of measurements was limited to animals judged to be
adult, as based on the possession of fully erupted
third molars and adult pelage. Three crude age
classes of ‘adult’ specimens were further identified
based on degree of upper molar wear, from little
(young adult), to moderate (full adult), to heavy (old
adult), generally following the patterns of coronal
change described by Carleton & Martinez (1991).
The following 21 analytical samples or operational
taxonomic units (OTUs) were used to generate the
various tabular summaries and to conduct univariate
and multivariate analyses. All OTUs are allopatric to
one another, each restricted to moist montane forest
in isolated mountain systems (Fig. 1). These are listed
in a northerly to southerly direction, accompanied by
their sample sizes, sample identification numbers as
used in illustrations, and collecting locality numbers
as referenced in the gazetteer (Appendix 1, Fig. 14);
localities represented by one to a few specimens were
not included in OTUs. Full provenance as given by
collectors and museum registration numbers of all
specimens examined is provided in the Taxonomic
summary.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
424
M. D. CARLETON and W. T. STANLEY
Kenya: (1) Taita Hills (localities 2–4, N = 47).
Tanzania: (2) Mt Kilimanjaro (localities 5–7; N = 38);
(3) North Pare Mts (localities 8, 9; N = 30); (4) Mt
Meru (locality 10; N = 20); (5) South Pare Mts (localities 13, 14; N = 29); (6) East Usambara Mts (localities
18–21; N = 29); (7) West Usambara Mts (localities 22,
23; N = 28); (8) Nguu Mts (localities 24, 25; N = 30);
(9) Nguru Mts (localities 26, 27; N = 18); (10) Ukaguru
Mts (localities 28, 29; N = 20); (11) Uluguru Mts
(localities 30–33; N = 21); (12) Malundwe Mts (locality
34; N = 21); (13) Rubeho Mts (localities 35–37;
N = 30); (14) Ndundulu Forest, Udzungwa Mts (Locality 38; N = 9); (15) Udzungwa Scarp Forest Reserve,
Udzungwa Mts (localities 39–42; N = 28); (16) Livingstone Mts (localities 44, 45; N = 16); (17) Poroto Mts
(localities 46–48; N = 25); (18) Mt Rungwe (localities
49–51; N = 65).
Malawi: (19) Misuku Mts (locality 52; N = 10); (20)
Lichenya Plateau (localities 55, 56; N = 29); (21) Mt
Mulanje (localities 58, 59; N = 29).
Standard descriptive statistics (mean, range, and standard deviation) were derived for adult specimens
(young, full, and old age classes combined) of the 21
OTUs. Means and ranges of external variables are
provided as guidance to identification but were not
input to morphometric analyses. One- and two-way
analyses of variance, discriminant function classification, and principal component scores were computed
using only the 18 craniodental variables, all of which
were first transformed to natural logarithms. Principal
components were extracted from the variance–
covariance matrix, and variable loadings are expressed
as Pearson product-moment correlation coefficients of
the derived principal components or canonical variates
with log transformations of the original cranial measurements. Hierarchical clustering of analytical samples was based on Mahalanobis distances between OTU
centroids and generated by the unweighted pair-group
method using arithmetic averages (UPGMA). Analytical procedures were implemented using statistical
packages contained in SYSTAT for Windows (Systat
Software Inc., Version 11.0, 2004) or PAST (Hammer,
Harper & Ryan, 2001; Version 2.07, 1999–2011).
For summarizing distributional patterns among terrestrial small mammals that inhabit Tanzanian mountains, we used two measures of faunal similarity, the
traditional Sørensen coefficient (also known as the Dice
Index) and the Raup–Crick index (Raup & Crick, 1979),
as applied to presence/absence data (Appendix 4) and
computed in PAST. In simulation studies to estimate
species richness, Raup–Crick’s index, a Monte Carlo
randomization procedure, was found to perform better
when data are spare or distributions are patchy compared with Sørensen’s (or Dice’s or Jaccard’s) coefficient, a distance metric (Travouillon et al., 2007).
PATTERNS OF MORPHOMETRIC
DIFFERENTIATION
NON-GEOGRAPHICAL
VARIATION
We excluded juvenile animals from univariate
sample statistics and multivariate analyses, but
appreciable age variation is nonetheless apparent
among the three adult age classes in our largest,
geographically homogeneous sample (Mt Rungwe,
OTU 18) of P. delectorum (melanotus). Most measurements, whether external or cranial, exhibit
linear, incremental increases in average size across
the three age classes (Table 1); accordingly, age class
as a categorical effect generated large, highly significant F-values in one-way analyses of variance for
a majority of variables. For 12 of 16 variables that
revealed pronounced age effects, the significant differences resided between the young adult versus full
and old adult age classes, not between the full and
old adult cohorts (as determined by Tukey post-hoc
pairwise comparisons). We attribute this result to
the underrepresentation of old adult animals in this
OTU and suspect that equal sample sizes would
also demonstrate significant size increase between
full and old adults. In general, stepwise increases in
mean size and corresponding F-values tend to be
larger for extreme dimensions (ONL, ZB) and those
measured on the facial region of the skull (LR, BR,
LD, LIF), compared with those recorded for the neurocranium (BBC, BOC, IOB). The exceptions to this
pattern of age-dependant increase in size among
cranial variables involve the two molar measurements (CLM, WM1), whose mean values remain
essentially the same regardless of age class
(Table 1). Unlike osseous portions of the skull, molar
size does not change following eruption and through
post-weaning growth, although crown height does
decrease with age and occlusal abrasion. The lack of
age influence is noteworthy because molar dimensions were found to contribute significantly to
among-group differentiation in the various multivariate results covered below.
In the same large sample from Mt Rungwe, sex as
a categorical effect contributed trivially and infrequently to within-sample variation for the 18 craniodental dimensions quantified, as indicated by the
magnitude and significance of F-values obtained
(Table 1). Mean values for males and females are
usually identical or nearly so, even for the very small
incisor and molar dimensions that were measured to
0.01 mm. Only one cranial variable (BBC) attained a
significant level of difference, an isolated result that
we are inclined to explain as a Type I sampling error.
The patterns of non-geographical cranial variation
attributable to age and sex factors in Praomys delectorum (melanotus) closely agree with results reported
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
425
Table 1. Arithmetic means of external and craniodental variables and results of one-way ANOVAs for sex and age cohorts
in adult Praomys from Mt Rungwe (OTU 18, N = 62; Y, A, and O = young, full, and old adult age class, respectively; see
Material and Methods for variable abbreviations)
Sex
Age
M
F
Variable
(N = 32)
(N = 30)
TOTL
HBL
TL
HFL
EAR
WT
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
220.5
101.0
119.5
24.4
20.2
28.4
28.4
13.3
11.8
7.9
6.2
4.5
9.9
4.8
9.3
5.3
8.0
5.9
5.4
3.2
4.6
4.43
1.36
1.34
213.4
97.9
116.2
23.6
19.8
25.1
28.2
13.3
11.6
7.8
6.2
4.5
9.9
4.8
9.3
5.2
7.9
5.9
5.5
3.2
4.6
4.43
1.35
1.35
Y
A
O
F(sex)
(N = 24)
(N = 30)
(N = 8)
F(age)
3.0
3.5
2.1
18.7***
1.6
6.0*
0.5
0.2
7.5**
0.8
2.2
3.7
0.1
0.5
0.0
1.5
0.4
0.1
0.8
0.0
0.3
0.0
1.5
0.1
204.1
93.3
111.8
23.8
19.2
22.5
27.3
12.8
11.5
7.7
6.1
4.4
9.5
4.6
8.8
5.1
7.5
5.6
5.4
3.0
4.5
4.43
1.35
1.27
223.4
102.7
121.3
24.2
20.4
28.7
28.9
13.5
11.8
7.9
6.2
4.5
10.2
4.9
9.6
5.3
8.2
6.1
5.5
3.3
4.6
4.42
1.36
1.37
228.6
105.3
124.6
24.3
20.9
30.9
29.1
13.7
11.9
8.1
6.3
4.6
10.2
4.9
9.7
5.4
8.4
6.1
5.5
3.3
4.6
4.44
1.36
1.43
18.7***
21.9***
13.0***
1.6
16.2***
17.4***
34.6***
33.5***
10.0***
19.5***
7.2**
8.2***
26.5***
21.6***
32.7***
5.0**
36.2***
23.1***
7.4**
14.5***
4.5*
0.2
0.2
18.5***
*P ⱕ 0.05; **P ⱕ 0.01; ***P ⱕ 0.00.
for many other African muroid rodents, including
Dasymys (Carleton & Martinez, 1991), Hylomyscus
(Carleton & Stanley, 2005), Lemniscomys (Van der
Straeten & Verheyen, 1978; Carleton & Van der Straeten, 1997), and Otomys (Carleton & Schaefer Byrne,
2006). In the following descriptive tables and morphometric comparisons, we combined measurements of
males and females and, except for a priori elimination
of juvenile specimens, did not statistically control for
age-related size effects in conveying multivariate
results. Although variation introduced by postweaning growth may be substantial within samples of
Praomys, it typically emerged as negligible relative to
those extracted factors that proved to be taxonomically informative.
We first address two key regional issues of taxonomic affinity using principal component analyses
(PCAs) and next summarize general patterns of differentiation among the 21 pre-defined groups using
discriminant function analysis (DFA).
THE
SAMPLE OF
PRAOMYS
FROM THE
NORTHERN
MALAWI
MISUKU MTS,
The Mulanje Plateau, the type locality of delectorum
Thomas (1910), is situated near the southernmost
distribution of delectorum-like populations (Fig. 1).
Accordingly, specimens from the Mulanje Massif and
adjoining highlands in southern Malawi have been
conventionally assigned to delectorum, whether as a
subspecies of P. jacksoni (Lawrence & Loveridge,
1953; Hanney, 1965) or of P. delectorum proper (Ansell
& Dowsett, 1988). Following the description of melanotus Allen & Loveridge (1933) from the Poroto Mts,
south-western Tanzania (Fig. 1), the taxonomic affinity and rank of populations in the adjoining Misuku
Mts, northern Malawi, have been variously interpreted. Lawrence & Loveridge (1953) considered
certain characteristics of the Misuku Mts Praomys to
be intermediate between delectorum and melanotus,
but ultimately judged the distinction as taxonomically
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
426
M. D. CARLETON and W. T. STANLEY
unrecognizable and classified the series with P. jacksoni delectorum. Hanney (1965: 602) appreciated the
size and pelage contrasts noted by Lawrence and
Loveridge, accepting that the differences between the
Praomys from the Misuku Mts and Mt Mulanje
approached ‘the conventional level of sub-specific differentiation’; nonetheless, he refrained from naming a
new race for the Misuku series. In assigning the
animals from the Misuku Mts to P. delectorum subspecies indeterminate, Ansell & Dowsett (1988) also
left the taxonomic status of northern versus southern
Malawi populations as unresolved.
In the following morphometric comparison, we
included samples of delectorum proper from Mt
Mulanje (OTUs 20, 21), Malawi, and those of melanotus from the Southern Highlands, Tanzania (Livingstone Mts, Poroto Mts, and Mt Rungwe – OTUs
16–18, respectively), localities referred as per the
original description of Allen & Loveridge (1933).
Specimens from the Misuku Mts (OTU 19), northern
Malawi, were not available until 1948.
Principal component ordination of craniodental
variables provides persuasive evidence that the
Misuku series is a geographical representative of
melanotus in northern Malawi. A scatterplot of the
first two components extracted depicts two constellations of points, coincident with the regions where the
type localities of delectorum and melanotus occur
(Fig. 2A); furthermore, factor scores of the types of
delectorum (BMNH 10.9.21.3) and melanotus (MCZ
26287) logically place each amongst the appropriate
regional samples. Although minimally overlapping at
their margins, the elongate scatters of specimen
scores possess major axes whose y-intercepts significantly differ (F = 202.3, P ⱕ 0.001) but whose slopes
are essentially the same (F = 0.06, P = 0.81); visually,
and statistically, the within-sample principal axes are
parallel. PCAs of craniodental variables commonly
disclose the first axis as a general size component, an
explanatory relationship also captured in our morphometric comparisons of the delectorum and melanotus
samples (all variables load positively and highly significantly, and correlations are uniformly moderate to
strong, r = 0.31–0.90; Table 2). Fewer input variables
correlate strongly with the second component, and
those coefficients vary greatly in magnitude and sign.
Noteworthy among those variables with a negative
sign, which intimates shape differences between the
taxa, are the smaller molar size (CLM, WM1) and
narrower zygomatic plate (BZP) that influence dispersion of specimens along PC II (Table 2). As a result
of such patterns of variable covariation, the seven
Misuku Mtn Praomys with intact skulls are clearly
interspersed among specimens of melanotus from the
Southern Highlands of Tanzania, not among those of
delectorum from southern Malawi (Fig. 2).
As demonstrated by Voss and colleagues in craniometric ordinations of closely related muroid species
(Voss, Marcus, & Escalante, 1990; Voss & Marcus,
1992), the orientation of such elliptical scatters,
oblique to the axes of PC I and II (e.g. Fig. 2A), may
complicate the biological interpretation of variable
loadings. The elongate spread of specimen scores, as
plotted in the plane of the first and second components,
reflects variable covariation due both to post-weaning
size increase within samples and to growth-invariant
differences between samples. A commonly employed
orthogonal rotational procedure is the Varimax
method, which redistributes the component loadings
such that the dispersion of the loadings is maximized
in the first few latent variables (principal components)
extracted and enhances their interpretation.
Application of Varimax rotation to the variance–
covariance matrix of the log-transformed data usefully
illuminates the variables that account for the conformation of sample dispersions of delectorum and melanotus and the separation of their major axes. Total
variation explained by the first two components
derived is approximately equal in the unrotated and
rotated ordinations (c. 68%); in contrast, the amount
explained by PC II is substantially greater (Table 2),
and longitudinal axes of the sample ellipses are reoriented to be approximately parallel with the first component (Fig. 2B). As before, PC I conveys general size,
with nearly all variables strongly and positively correlated (Table 2). ‘Size’ in the context of the rotated
first component, however, corresponds largely to
changes in the head skeleton associated with postweaning growth; accordingly, in one-way ANOVAs of
PC I scores, age class as categorical effect contributes
substantially to variation along that axis and withinsample dispersion (multiple r = 0.67, F = 40.5,
P ⱕ 0.001). Those dimensions that do not load significantly on PC I underline the interpretation of this
factor as capturing age-related, size increase: length
(CLM) and width (WM1) of the molars are the sole
exceptions to significant loadings on this rotated factor
(Table 2), a finding consistent with the absence of
age-class effects attributed to these variables in the
univariate tests (Table 1). On the other hand, taxon as
group effect in one-way ANOVAs does not contribute to
variation in PC I scores (multiple r = 0.02, F = 0.07,
P = 0.80). Growth-invariant, mensural differences
between samples of delectorum and melanotus are now
more clearly appreciated by those variables that correlate strongly with the rotated second component,
which is aligned perpendicular to the major axes of the
sample ellipses. A one-way ANOVA of specimen scores
on this eigenvector demonstrates the overwhelming
influence of taxon as group effect (multiple r = 0.88,
F = 538.4, P ⱕ 0.001) and only minor contribution
of age class (multiple r = 0.31, F = 5.4, P ⱕ 0.01).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
A
427
3
delectorum
Holotypes
melanotus
Misuku Mts
2
Y = 0.62X + 1.29
F= 29.0, P < .001
PC II (12.3%)
1
0
delectorum
-1
Y = 0.58X -0.76
F = 62.6, P < .001
melanotus
-2
-3
-3
B
-2
-1
0
1
2
3
2
3
PC I (56.4%)
3
delectorum
melanotus
Holotypes
2
melanotus
RPC II (31.2%)
1
0
delectorum
-1
-2
-3
-3
-2
-1
0
1
RPC I (37.4%)
Figure 2. Two scatter plots depicting results of principal component analysis of 18 log-transformed craniodental
variables as measured on 157 intact specimens representing samples of delectorum (OTUs 20, 21) and melanotus (OTUs
16–19). The factor scores of the type specimens of delectorum and melanotus are indicated by small crosses; see Table 2
for variable correlations and variance explained. A, projection of unrotated specimen scores onto the first and second
principal components (PC) extracted; major axes of the species constellations and regression statistics are indicated (see
text for discussion). Individuals from the Misuku Mts (OTU 19), northern Malawi, which systematists have inconsistently
treated as geographical representatives of delectorum or melanotus, are interspersed among examples of the latter
species. B, projection of specimen scores, after varimax rotation, onto the first and second principal components (PC)
extracted. Reorientation of major axes of the species constellations maximizes age variation along PC I, whereas taxon
differences are consolidated mostly along PC II (see text for discussion).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
428
M. D. CARLETON and W. T. STANLEY
Table 2. Results of principal component analysis of Praomys delectorum and P. melanotus; see Figure 2 for plots of
principal components and Material and Methods for variable abbreviations
Correlations
Rotated correlations
Variable
PC I
PC II
RPC I
RPC II
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
Eigenvalues
Percent variance
0.86***
0.90***
0.63***
0.31***
0.49***
0.50***
0.85***
0.72***
0.71***
0.46***
0.86***
0.75***
0.69***
0.88***
0.49***
0.42***
0.52***
0.75***
0.024
56.4
0.39***
0.01
0.20*
0.48***
0.29***
0.18*
0.27**
0.30***
0.54***
-0.13
0.34***
0.23**
-0.20*
-0.43***
-0.02
-0.50***
-0.53***
0.24*
0.005
12.3
0.91***
0.69***
0.61***
0.54***
0.57***
0.50***
0.83***
0.75***
0.89***
0.35***
0.88***
0.65***
0.38***
0.37***
0.35***
-0.01
0.04
0.73***
0.016
37.4
0.26**
0.58***
0.26**
-0.16*
0.09
0.18*
0.34***
0.22*
0.05
0.27**
0.30***
0.41***
0.61***
0.91***
0.34***
0.64***
0.74***
0.31***
0.013
31.2
*P ⱕ 0.05; **P ⱕ 0.01; ***P ⱕ 0.001.
Collectively, the sign and magnitude of coefficients on
the rotated PC II describe the overall larger size of the
melanotus skull compared with that of delectorum
(Tables 2, 5), in particular its more elongate rostrum
(LR, LD, LIF), broader zygomatic arches and expansive plate (ZB, BZP), large hard palate (LBP, BBP), and
robust dentition (CLM, WM1, DI).
THE
PRAOMYS FROM THE UDZUNGWA
MTS, CENTRAL TANZANIA
SAMPLE OF
In their description of Praomys tullbergi melanotus,
most specimens that Allen & Loveridge (1933)
referred to their new subspecies originated from
localities in the Southern Highlands, mountains
that lie to the west of the Makambako Gap (Poroto
Mts, Livingstone Mts, Mt Rungwe; Fig. 1). Further,
they assigned one locality situated to the east of the
Gap (Kigogo, Udzungwa Mts), an allocation which
documented melanotus in the EAM, at least in the
western portion. Toward the eastern reaches of the
EAM, the small Praomys collected from sites in the
Uluguru and Usambara Mts have been identified as
taitae (Allen & Loveridge, 1927; Swynnerton &
Hayman, 1951), the form that Heller (1912) named
from the nearby Taita Hills, southern Kenya.
The following morphometric comparisons incorporated the sample of taitae sensu stricto (s.s.) from the
Taita Hills (OTU 1), Kenya, and again those of melanotus from the Southern Highlands, Tanzania (Livingstone Mts, Poroto Mts, and Mt Rungwe – OTUs
16–18, respectively). Unfortunately, the Kigogo specimen (MCZ 26498) reported by Allen & Loveridge
(1933) is a juvenile with an imperfect skull, raising
doubts about the accuracy of the original determination. In its stead, we included the excellent series
recently collected from the Udzungwa Scarp Forest
Reserve (OTU 15). Our principal component analyses
repeated the prior stepwise approach, first looking at
the plot of specimen scores based on conventional
extraction of principal components, followed by
Varimax rotation of the derived components.
Specimens that represent the regions of the type
localities of melanotus and taitae are disposed as
non-overlapping multivariate scatters, each circumscribing their respective types (MCZ 26287 and
USNM 181797) as plotted in the plane of the first two
principal components (Fig. 3A). The mathematical
properties of these dual constellations are the same
as those obtained in the PCA of delectorum and melanotus: the major axes have significantly different
y-intercepts (F = 414.9, P ⱕ 0.001) and the lines are
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
429
A
Holotypes
melanotus
taitae
Udzungwa Mts
3
Y = 0.56X + 1.19
F = 40.4, P < .001
2
PC II (16.4%)
taitae
1
0
-1
melanotus
-2
Y = 0.47X - 0.83
F = 74.3, P < .001
-3
-3
B
-2
-1
1
0
2
PC I (55.9%)
3
melanotus
taitae
Holotypes
2
melanotus
RPC II (32.2%)
1
0
taitae
-1
-2
-3
-3
-2
-1
0
1
2
3
RPC I (40.0%)
Figure 3. Two scatter plots depicting results of 18 log-transformed craniodental variables as measured on 155 intact
specimens representing samples from the Udzungwa Mts (OTU 15) and regions of the type localities of Praomys
melanotus (OTUs 16–18) and P. taitae (OTU 1). The factor scores of the type specimens of melanotus and taitae are
indicated by small crosses; see Table 3 for variable correlations and variance explained. A, projection of unrotated
specimen scores onto the first and second principal components (PC) extracted; major axes of the species constellations
and regression statistics are indicated (see text for discussion). Specimens from the Udzungwa Mts, a locality which Allen
& Loveridge (1933) had allocated to their new species melanotus, are aligned with examples of P. taitae. B, projection of
specimen scores, after varimax rotation, onto the first and second principal components (PC) extracted. Reorientation of
major axes of the species constellations maximizes age variation along PC I, whereas taxon differences are consolidated
mostly along PC II (see text for discussion).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
430
M. D. CARLETON and W. T. STANLEY
Table 3. Results of principal component analysis of Praomys melanotus and P. taitae; see Figure 3 for plots of principal
components and Material and Methods for variable abbreviations
Correlations
Rotated correlations
Variable
PC I
PC II
RPC I
RPC II
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
Eigenvalues
Percent variance
0.93***
0.88***
0.74***
0.63***
0.65***
0.62***
0.91***
0.70***
0.76***
0.69***
0.94***
0.74***
0.72***
0.87***
0.51***
0.43***
0.49***
0.52***
0.026
55.9
0.26**
-0.11
-0.23**
0.26**
-0.31***
-0.13
0.13
0.41***
0.43***
-0.08
0.08
0.00
-0.43***
-0.27**
-0.32***
-0.77***
-0.71***
0.74***
0.008
16.4
0.88***
0.60***
0.42***
0.65***
0.31***
0.41***
0.79***
0.81***
0.86***
0.51***
0.78***
0.55***
0.29***
0.50***
0.18*
-0.15
-0.07
0.87***
0.019
40.0
0.39***
0.64***
0.65***
0.19*
0.65***
0.49***
0.47***
0.13
0.15
0.51***
0.53***
0.46***
0.79***
0.76***
0.56***
0.87***
0.86***
-0.24**
0.015
32.2
*P ⱕ 0.05; **P ⱕ 0.01; ***P ⱕ 0.001.
parallel, their slopes lacking significant contrast
(F = 0.79, P = 0.38). Moreover, relationships between
the log-transformed input variables and extracted
components are broadly comparable: loading coefficients of all variables on the first component are
uniformly positive and correlations range from moderate to large (r = 0.43–0.94; Table 3); in contrast,
those on the second component represent a mixture of
signs, many correlations are trivial, whereas some are
large and highly significant, in particular those of the
dentition (CLM, WM1, DI). Such patterns of variable
relationships, distilled from a multivariate perspective, disclose the affinity of the Udzungwa animals
with topotypic examples of taitae (Fig. 3A), not with
representatives of melanotus from west of the Makambako Gap.
A scatterplot of the first two components removed
after Varimax rotation depicted the same elliptical
clouds of specimen scores, corresponding to our
regional samples of melanotus and taitae, now reoriented such that the major axes of sample dispersion
are more or less parallel with the vector of the first
component (Fig. 3B). The cumulative amount of
variation explained by PC I and II remained approximately the same as before (72%), although the per
cent variance captured by each is more evenly distributed (40% and 32.2%, Table 3). Post-weaning
increase in size (growth) corresponds to the long axis
within each sample dispersion; that is, most variable
correlations with the first component are positive and
moderate to large (r = 0.41–0.88; Table 3), and a oneway ANOVA of rotated PC I scores with age class as
categorical effect accounts for appreciable variation
(multiple r = 0.71, F = 52.9, P ⱕ 0.001). As in the
delectorum–melanotus Varimax analysis, the only
variables that lack correlation with the first component are those measured on the molars (CLM, WM1),
a result concordant with the lack of age-class effect
recovered for these dimensions in univariate ANOVAs
(Table 1). An ANOVA of rotated PC I scores uncovered
no contribution of the effect taxon to mean differences
(multiple r = 0.07, F = 0.84, P = 0.36). Visually and
statistically, growth-invariant size discrimination
between samples of melanotus and taitae is readily
apparent along the rotated second component
(Fig. 3B): one-way ANOVAs of rotated PC II specimen
scores are highly significant for taxon as categorical
effect (multiple r = 0.89, F = 604.2, P ⱕ 0.001) but not
for age class (multiple r = 0.10, F = 0.55, P = 0.65).
Variables that influence the separation of the major
axes of the taxonomic samples in general capture the
more massive skull of melanotus relative to taitae; of
particular note are the broader neurocranium (BBC,
BOC, IOB), expanded zygomatic plate (BZP), and
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
robust molars (CLM, WM1) of melanotus (Tables 3, 5).
Variables that load heavily on PC II after Varimax
rotation do not precisely mirror the PC II loadings
obtained in the conventional PCA; among other contrasts, the stout proportions of the rostrum (LR, LD,
LIF) of melanotus are only indicated after Varimax
rotation but not before (Table 3). In spite of the
overall gracile size and proportions of taitae compared
with melanotus in most craniodental dimensions, the
heavier build of its incisors (DI) is emphasized by the
sign and magnitude of coefficients on the rotated
second component (Table 3).
RESULTS
OF
DFA
Prior OTU definitions, ordered around distinct mountain units, introduced substantial structure to the
variance–covariance matrix, resulting in pronounced
differences
between
group
centroids
(Wilks’
lambda = 0.005, F = 9.19, P ⱕ 0.00001). Extraction of
the first two canonical variates from DFA of the 21
predefined OTUs disclosed three phenetic associations, whether visually suggested by the concentration of individual specimen scores (Fig. 4A) or
revealed by the clusters of OTU centroids (Fig. 4B).
The percentage of specimens correctly assigned, with
jackknifed sampling, to their OTU of origin widely
varies from 22 to 85%. Most classification errors,
however, occurred among OTUs within one of the
three major clusters; few individuals were misclassified between OTUs representing another principal
cluster (correct collective classifications among OTUs
1–15 = 98%, among OTUs 16–19 = 98%, among OTUs
20–21 = 90%). Although general size does not necessarily emerge as an explanation for the dispersion of
specimen scores along the first canonical variate
defined in a DFA, it does in this instance: samples are
arrayed from larger to smaller as CV 1 increases. The
loadings of most variables are moderate on the first
canonical axis, but the influence of two are paramount, those of the molars (CLM, WM1) as indicated
by the size of the CV 1 coefficients and by the magnitude of F-values derived from univariate ANOVAs
with OTU as categorical effect (Table 4). Most correlations with the second canonical axis are insignificant or trivial, but breadth of the zygomatic plate
(BZP) is negative and large (Table 4). The interplay of
these variable relationships delineates the three OTU
clusters: those (16–19) with a large skull, robust
molars, and broad zygomatic plate; a second set (20,
21) with intermediate craniodental size and narrow
zygomatic plate; and a third morphological group
(1–15) with a smaller skull and delicate molars
(Fig. 4B).
Scientific names are available for each of the craniodental morphotypes portrayed by scatterplots of the
431
first two canonical variates. OTU cluster 1–15
includes the topotypic series of taitae (Taita Hills,
OTU 1), that of 16–19 contains the type region of
melanotus (Poroto Mts, OTU 17), and the third group
20–21 includes our series from Mt Mulanje, where the
type of delectorum originated. Entered as unknowns
in a three-group DFA and classified according to posterior probabilities of group membership, three of four
type specimens are unambiguously assigned to their
appropriate geographical cluster (Fig. 4C). Groupmembership probabilities for the types of melanotus
(MCZ 26287) and taitae (USNM 181797) approached
statistical certainty (P = 1.00 and P = 0.98, respectively); in addition, the holotype of octomastis (AMNH
55718), named from the Mbulu Forest in the Northern Highlands (Fig. 1), is classified with the taitae
samples at a very high level of probability (P = 0.99).
The canonical disposition and post-hoc membership
probability of the type of delectorum (BMNH
10.9.21.3), however, are not so clear-cut (Fig. 4C). Its
highest probability of membership is appropriately
with the Mt Mulanje series but at an inconclusive
level (P = 0.67); it was secondarily assigned to the
taitae cluster, with low confidence of membership
(P = 0.33).
The ‘atypical’ multivariate behaviour of the type of
delectorum may be attributable to several factors,
probably acting in concert to account for its indecisive
a posteriori classification. Two seem most influential
to us. (1) Although Thomas (1910) described his type
(and single specimen) of delectorum as an adult,
Hanney (1965) characterized it as a young adult, an
estimation that corresponds to its youthful age as
judged by Paula Jenkins (BMNH) and by the photographs she supplied to us. Because size grades from
large to small along CV 1, the discriminant coefficients would displace the young-adult type toward the
right margin of dispersion within the Mt Mulanje
samples, outside the 1 SD confidence envelope around
the grand centroid. (2) Certain anatomical regions of
the type skull are broken, witness to a century of
handling and measuring by taxonomists. In particular, the zygomatic arches are crushed inwards,
damage that could account for substantial undermeasurement of this variable (ZB), which loads
moderately high on CV 1 (Table 4). When ZB was
excluded, regeneration of the DFA with 17 variables
did place the type nearer the centroid but still outside
the 1 SD confidence circle. In spite of the statistically
inconclusive results regarding the association of Thomas’s type, we are confident that the name delectorum applies to the distinctive Praomys populations
that occur in southernmost Malawi. In contrast to the
DFA results, the delectorum holotype is clearly placed
among the Mulanje series in PCAs of delectorum and
melanotus from regions of their type localities (see
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
432
M. D. CARLETON and W. T. STANLEY
A
B
6
6
4
4
20
CV 2 (15.6%)
21
2
2
16
0
19
17
-2
0
18
1--15
-2
-4
-4
-6
-4
0
-2
2
4
-6
-4
0
-2
CV 1 (49.9%)
2
4
CV 1 (49.9%)
C
6
4
delectorum
2
octomastis
0
melanotus
taitae
-2
-4
-6
-4
-2
0
2
4
Figure 4. Three scatter plots depicting results of discriminant function analysis performed on 18 log-transformed
craniodental variables, as measured on 541 intact adult specimens representing 21 OTUs of the Praomys delectorum
complex. A, projection of individual specimen scores onto the first two canonical variates (CV) extracted. B, projection of
centroids for the 21 OTUs onto the first two canonical variates (see Material and Methods for general locality and sample
sizes; bars indicate ± 1 standard error of the mean for a sample centroid); OTU numbers 1–15 are placed approximate
to the entire cluster in view of the extensive overlap and visual congestion among those analytical samples. C,
multivariate disposition of the four type specimens entered as unknowns and based on a posteriori classification using
the discriminant function coefficients; confidence envelopes represent 1 standard deviation around a grand centroid and
enclose approximately 68% of specimen scores for each. See Table 4 for variable correlations and variance explained.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
Table 4. Results of 21-group discriminant function analysis and univariate ANOVAs for OTU as categorical effect;
see Figure 4 for plots of canonical variates and Material
and Methods for variable abbreviations
Correlations
Variable
CV 1
CV 2
F(OTU)
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
Canonical
Correlations
Eigenvalues
Percent variance
-0.17***
-0.53***
-0.55***
-0.18***
-0.38***
-0.51***
-0.27***
0.03
0.11*
-0.57***
-0.32***
-0.18***
-0.70***
-0.24***
-0.19***
-0.88***
-0.85***
0.07
-0.08
-0.26***
0.05
0.19***
-0.00
0.04
0.09*
-0.07
-0.10*
0.09*
-0.09*
-0.28***
-0.10*
-0.77***
-0.22***
0.00
-0.10*
-0.17***
3.9***
13.2***
14.1***
4.9***
9.9***
13.5***
5.2***
2.5***
4.0***
14.3***
6.1***
5.6***
23.3***
20.9***
7.0***
56.6***
49.4***
7.3***
0.91
4.70
50.1
0.77
1.45
15.5
*P ⱕ 0.05; **P ⱕ 0.01; ***P ⱕ 0.001.
Fig. 2). Principal component ordinations distill covariation patterns based on measurements of individual
specimens, not on dispersion among centroids of predefined groups. Furthermore, the narrower regional
context of the PCA comparisons highlighted more
variables that influence morphometric segregation of
the samples, differences that are obscured in the
21-group DFA.
Broad phenetic associations among all 21 OTUs,
based on Mahalanobis distances between group centroids, delineate the same three craniodental morphologies uncovered in the preceding PCAs and DFAs,
evidence that collectively supports recognition of
three species. The deepest clustering divisions, each
reinforced by high bootstrap support (86–99%), sensibly cohere to major geographical regions and areas
of endemism (Fig. 5): the two series from the Mulanje
Massif, southernmost Malawi (P. delectorum); the
samples from the Southern Highlands to the southwest of the Makambako Gap, southern Tanzania and
northern Malawi (P. melanotus); and the many OTUs
representing mountains within the EAM (Udzungwa
Mts to Taita Hills) and Northern Highlands, central
433
Tanzania to southern Kenya (P. taitae). We attach
little taxonomic or biogeographical significance to the
various pair-groups recovered within the P. taitae
cluster in view of their short branch lengths and low
bootstrap values (ⱕ 70%). Nevertheless, those associations that consistently emerged deserve comment.
For one, the sample from the Ukaguru Mts typically
appeared as pair-group to all other OTUs from the
EAM and Northern Highlands (Fig. 5), a seemingly
anomalous result in view of its location within the
middle of the EAM chain (see Fig. 1). The unique
differentiation of the Ukaguru population among
EAM Praomys was uncovered in other multivariate
analyses (e.g. see the following comparison of
Praomys and Hylomyscus populations in the EAM,
Fig. 12). For another, we are surprised by the consistent linkage of the topotypic series of taitae from the
Taita Hills and the two samples from the Udzungwa
Mts, mountains positioned at the opposite ends of the
EAM. Most other OTUs drawn from the eastern EAM
clustered with one another or with samples from the
Northern Highlands. Additional research employing
other data sources is needed to corroborate the stability of such recurrent morphometric patterns.
TAXONOMIC SUMMARY
We regard the foregoing results as supportive of three
species within the Praomys delectorum species group:
P. delectorum (Thomas, 1910); P. melanotus Allen &
Loveridge (1933); and P. taitae (Heller, 1912), including Praomys jacksoni octomastis Hatt (1940) as junior
synonym. Additional justification for application of
these epithets and past interpretations of their status
and relationship are considered within Remarks
under the following species accounts. The synonymies
trace earliest identification and first subsequent
usage of other name combinations. Type localities are
quoted verbatim as given in original descriptions,
with updated geopolitical equivalents supplied in
square brackets. Specimens examined include all
individuals personally seen and identified by us; see
Appendix 1 for geographical coordinates of principal
collecting localities.
To avoid repetition of morphological description in
the specific accounts, we first summarize traits
shared by members of the Praomys delectorum group
according to our revised understanding of species
limits. This characterization, in telegraphic style,
draws heavily upon the morphological characters
covered by Lecompte, Granjon & Denys (2002a:
Appendix 2) in their phylogenetic study of the
Praomys complex and upon the character contrasts
enumerated by Carleton, Kerbis Peterhans & Stanley
(2006: 298–303) between Praomys delectorum (taitae)
and large species of Hylomyscus.
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434
M. D. CARLETON and W. T. STANLEY
Malundwe Mts (12)
Mt Meru (4)
96
Nguu Mts (8)
86
Nguru Mts (9)
Uluguru Mts (11)
E Usambaras (6)
N Pare Mts (3)
Rubeho Mts (13)
86
P. taitae
W Usambaras (7)
Mt Kilimanjaro (2)
S Pare Mts (5)
Taita Hills (1)
95
80
Udzungwa Mts (14)
72
Udzungwa Mts (15)
Ukaguru Mts (10)
Lichenya Plateau (20)
99
P. delectorum
Mt Mulanje (21)
Livingstone Mts (16)
P. melanotus
99
Misuku Mts (19)
100
Poroto Mts (17)
99
Mt Rungwe (18)
120
100
80
60
40
20
0
Mahalanobis D 2
Figure 5. Cluster diagram (UPGMA) based on average Mahalanobis distances between the 21 OTU centroids as derived
from discriminant function analysis (coefficient of cophenetic correlation = 0.938; also see Fig. 4). Bootstrap values are
indicated for those nodes that were consistently defined (ⱖ 70%, 1000 iterations); mountain system and OTU identifier
are indicated for each terminal OTU; species recognized herein are identified for those stems that subtend major
geographical associations among the analytical samples.
SIZE
AND EXTERNAL FEATURES
Size small compared with other Praomys (weight ª
25–30 g, HFL ª 23–25 mm, ONL usually < 30 mm).
Mammary glands number eight, arranged as one pair
of pectoral mammae, a pair of postaxillary mammae,
and two inguinal pairs. Fur of adults soft and relatively short, dorsal–ventral pelage contrast well
marked, reddish brown above and variously grey
below. Juvenile pelage distinct from that of adults,
drably coloured; dorsal pelage sooty brown to deep
umber, ventral pelage slate grey to blackish; dorsal–
ventral pelage contrast inconspicuous. Tail moderately longer than head and body (TL ª 115–125% of
HBL), generally monocoloured; caudal hairs short,
tail appearing macroscopically naked and revealing
fine scale pattern; tail tip lacking terminal tuft or
pencil. Hindfoot relatively long and narrow, the fifth
digit shorter than middle digits II–IV; plantar pads
six, the hypothenar small but distinct.
HEAD
AND POST-CRANIAL SKELETON
Cranium moderately constructed for size, dorsal vault
weakly arched, nearly straight over the interorbitrostrum. Rostrum moderately long (LR ª 35% of ONL).
Braincase smooth and rounded, lacking temporal and
lambdoidal ridging (Fig. 6); fronto-parietal suture
bluntly acute at midsection or evenly bowed; interparietal large, nearly as wide as the rear border of the
parietals, but not laterally contacting the squamosals.
Lateral braincase perforated by spacious postglenoid
foramen and moderate-sized subsquamosal fenestra
(Fig. 7), the two openings separated by a long, slender
hamular process (tympanic hook of Lecompte et al.,
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SYSTEMATICS OF PRAOMYS
435
Figure 6. Dorsal (top row) and ventral (bottom row) views (about 2¥) of adult crania of the three species of the Praomys
delectorum group recognized here: A, P. delectorum (FMNH 181214; ONL = 29.0 mm), a male from Lichenya Hut, Mt
Mulanje, 1840 m, Malawi; B, P. melanotus (FMNH 163682; ONL = 29.9 mm), a female from 5 km east of Ilolo, Rungwe
Forest Reserve, Mt Rungwe, 1870 m, Tanzania; C, P. taitae (FMNH 153979; ONL = 28.7 mm), a male from 3 km east and
0.7 km north of Mhero, Chome Forest Reserve, South Pare Mts, 2000 m, Tanzania.
2002a). Interorbital shape weakly cuneate, rear
supraorbital edges divergent and sharp but not
forming projecting shelf or elevated ridging. Zygomatic
arches weakly convergent anteriorly to slightly bowed
laterally at midsection; anterior edge of zygomatic
plate usually straight and nearly vertical, dorsal notch
moderately incised. Incisive foramina long (LIF ª 70–
75% of LD) and narrow, parallel sided without middle
expansion, extending caudad to or just beyond the level
of the anterior root of M1s (Fig. 6). Hard palate
smooth, extending beyond the end of M3s; anterior
border of palatine bones even with M1–M2 junction;
posterior palatine foramina set within the maxillary–
palatine suture, just behind anterior border of
palatines and at level of middle root of M2. Mesopterygoid fossa medium in width, sides parallel and anterior
border squared or bluntly U-shaped; parapterygoid
fossae shallow, much wider than the mesopterygoid
fossa. Alisphenoid strut typically present. Ectotympanic bullae moderately inflated as for the genus,
obscuring all but a narrow posteromedial sliver of the
periotic in ventral view; anterolateral bullar rim bears
a single short spine (antero-external apophysis of
Lecompte et al., 2002a), either free or lapping ventral
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436
M. D. CARLETON and W. T. STANLEY
by a crease on the anterolateral border of first
chevron; t7 absent; t9 (metacone) present as short
crest or spur off the large t8 (hypocone), not so discrete as the t3. M2 also with t3, which is much
smaller than t1 but uniformly present and discernable even on moderately worn teeth. Anteroconid of
m1 deeply bilobate, narrower than and medially conjoined to the anterior chevron (protoconid-metaconid);
strong labial cingulum emerges from anterolabial
conulid but not forming distinct anterior labial
cusplet; posterior labial cusplet of m1 large, consistently present and positioned at labial margin of
posterior chevron (hypoconid-entoconid). Posterior
labial cusplet smaller and irregularly formed on m2,
occasionally absent; anterolabial cingulum of m2
(labial cone of Lecompte et al., 2002a) present and
well developed. Posterior cingulum of m1–2 well
defined, transversely wide but thin anteriorly–
posteriorly. Upper molars each anchored by three
roots and the lower molars by two.
PRAOMYS DELECTORUM (THOMAS, 1910)
(FIGS 6–8; TABLES 5, 6)
Figure 7. Lateral view (about 2¥) of adult crania of the
three species of the Praomys delectorum group (same
specimens as illustrated in Fig. 6): A, P. delectorum; B, P.
melanotus; C, P. taitae.
edge of alisphenoid; dorsal roof of mastoid bulla incomplete, perforated by large fenestra.
Coronoid process of dentary short and pointed, dorsally extending about the same height as the condylar
process; sigmoid notch shallow; alveolus of lower
incisor extends below base of coronoid process,
forming an indistinct lateral mound not a raised
capsular projection.
Entepicondylar foramen (foramen supracondylicus
of Lecompte et al., 2002a) of humerus absent (see
Appendix 2 for skeletons examined).
DENTITION
Upper incisors opisthodont; enamel surface of upper
and lower incisors pigmented a dull, pale yellow.
Molar rows oriented parallel to one another, slightly
shorter than hard palate and anteriorly reaching to
level of rear border of zygomatic plate; M3 small, less
than half the length or area of M2. Occlusal surface
tuberculate, cusps transversely joined to form typical
murid chevrons. Anterior chevron of M1 broad,
reflecting the large t1 and conspicuous t3 (labial
anteroconule), the latter strongly demarcated from t2
Epimys delectorum Thomas, 1910: 430; type locality –
‘Mlanji Plateau, S. Nyasaland [Malawi]. Alt. 5500’
[1675 m]’; type specimen – BMNH 10.9.21.3, a young
adult female collected 2 May 1910 by S. A. Neave.
Praomys delectorum, Thomas, 1926: 178 (name
combination, emended generic diagnosis with allocation of species).
Praomys jacksoni delectorum, G. M. Allen, 1939:
410 (name combination, retention as valid
subspecies).
Rattus [(Praomys)] tullbergi delectorum, Ellerman,
1941 (name combination, retention as valid subspecies).
Rattus (Praomys) morio delectorum, Ansell,
1957: 546 (name combination, retention as valid
subspecies).
Praomys delectorum, Davis, 1965: 131 (resurrection
as valid species, allocation of synonyms).
Praomys [(Praomys)] delectorum, Misonne, 1974: 27
(name combination, subgeneric classification).
Praomys delectorum delectorum, Ansell, 1978: 82
(retention as valid species and subspecies).
Emended diagnosis: A species of the Praomys delectorum group characterized by intermediate cranial
and molar size (Table 5); zygomatic plate narrow,
usually ⱕ 2.8 mm, and incisors delicate compared
with P. melanotus and P. taitae.
Distribution: Forested highlands of extreme southern
Malawi, including the Cholo Mts, Mt Mulanje, and
Zomba Plateau (Fig. 10); known elevational range
1000–1840 m.
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SYSTEMATICS OF PRAOMYS
437
Figure 8. Dorsal (left set) and ventral (right set) views of adult round skins (about 0.5¥), illustrating ‘typical’ pelage
patterns of the three species of the Praomys delectorum group recognized here: AA′, P. delectorum (FMNH 181237; Total
Length = 223 mm), a male from Chisongeli Forest, Mt Mulanje, 1575 m, Malawi; BB′, P. melanotus (FMNH 205299;
Total Length = 234 mm), a male from Ngozi Crater, Poroto Mts, 2250 m, Tanzania; CC′, P. taitae (FMNH 150346; Total
Length = 240 mm), a male from 4.5 km ESE of Amani, East Usambara Mts, 900 m, Tanzania.
Morphological description and comparisons: Differences between the three taxa in external measurements are even less apparent than the subtle
craniodental size and shape contrasts that emerged in
morphometric analyses. As a crude generalization,
samples of P. melanotus average larger in most external dimensions, those of P. delectorum are intermediate, and those of P. taitae the smallest. Such mean
differences for these large, age-sensitive variables are
slight, however, and measurement ranges extensively
overlap one another (Table 5). On average, examples
of P. delectorum and P. taitae do have longer tails,
absolutely and relative to head-and-body length
(TL ª 120–125% of HBL), compared with tail length
in P. melanotus (TL ª 115–120% of HBL). Pinnae
length in P. delectorum averages the largest among
the three species.
The dorsal pelage colour in all three species is some
shade of brown, the subtle differences among them
involving the concentration of blackish hairs on the
back and rump and the relative brightness evident
along the flanks (Fig. 8). In series of P. delectorum, the
upperparts vary from dull buffy brown to medium
brown, tending to dark brown over the middle dorsum
and rump. The shoulders, flanks, and hips are brighter
in tone, the hairs possessing buffy to pale ochracreous
tips and the general effect grading to yellowish brown
or rich tawny. Most specimens from Mt Mulanje
possess a hind foot with a dusky metatarsum and
whitish toes. The rostrum, cheeks, and crown exhibit
more grey. The basal three-quarters of ventral hairs
are dark slate, tipped with buff to pinkish buff. The
prominence of the pinkish buff tips produces a moderate to strong buffy overwash that only partially
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438
M. D. CARLETON and W. T. STANLEY
Table 5. Descriptive statistics for the Praomys delectorum group (statistics include the sample mean, standard deviation,
observed range, and sample size in parentheses; see Material and Methods for variable abbreviations)
P. delectorum
P. melanotus
P. taitae
Variable
Mt Mulanje
Poroto Mts
Taita Hills
TOTL
223.8 ± 12.4
202–226 (29)
100.3 ± 6.1
90–115 (29)
124.7 ± 7.3
112–142 (29)
24.1 ± 0.6
23–25 (29)
21.0 ± 0.8
18–22 (29)
26.4 ± 3.9
19.5–35.5 (27)
28.0 ± 0.8
26.3–30.0 (29)
12.8 ± 0.3
12.0–13.5 (29)
11.6 ± 0.3
11.1–11.9 (29)
7.9 ± 0.2
7.5–8.3 (29)
6.2 ± 0.2
5.9–6.5 (29)
4.5 ± 0.1
4.2–4.7 (29)
9.7 ± 0.4
8.7–10.7 (29)
4.7 ± 0.2
4.3–5.1 (29)
9.4 ± 0.4
8.3–10.5 (29)
5.1 ± 0.3
4.4–5.7 (29)
7.7 ± 0.4
7.0–8.7 (29)
5.6 ± 0.3
4.9–6.2 (29)
5.3 ± 0.1
5.0–5.5 (29)
2.7 ± 0.1
2.4–3.0 (29)
4.5 ± 0.1
4.3–4.8 (29)
4.24 ± 0.10
4.02–4.44 (29)
1.28 ± 0.04
1.18–1.36 (29)
1.33 ± 0.07
1.18–1.49 (29)
228.7 ± 10.2
207–247 (24)
106.3 ± 5.0
95–120 (24)
122.4 ± 7.5
110–140 (24)
24.6 ± 0.9
23–26 (24)
20.1 ± 1.7
19–25 (24)
32.0 ± 3.6
24.0–37.5 (17)
28.7 ± 1.0
26.5–30.1 (24)
13.5 ± 0.5
12.3–14.3 (24)
11.8 ± 0.2
11.4–12.4 (24)
8.0 ± 0.2
7.6–8.3 (24)
6.2 ± 0.1
6.1–6.6 (24)
4.5 ± 0.1
4.2–4.8 (24)
10.0 ± 0.5
9.0–10.7 (24)
4.7 ± 0.2
4.3–5.1 (24)
9.5 ± 0.5
8.8–10.4 (24)
5.2 ± 0.2
4.9–5.6 (24)
8.1 ± 0.4
7.1–9.1 (24)
6.0 ± 0.2
5.6–6.5 (24)
5.5 ± 0.1
5.3–5.8 (24)
3.3 ± 0.2
3.0–3.8 (24)
4.5 ± 0.1
4.1–4.8 (24)
4.38 ± 0.11
4.15–4.55 (22)
1.35 ± 0.04
1.26–1.43 (22)
1.38 ± 0.08
1.21–1.50 (24)
228.1 ± 8.0
210–245 (33)
102.0 ± 4.9
95–112 (33)
126.1 ± 5.9
112–136 (33)
23.1 ± 0.8
21–25 (33)
19.4 ± 0.7
18–21 (32)
25.3 ± 3.7
21.0–31.0 (7)
28.0 ± 1.0
25.8–29.8 (39)
12.8 ± 0.4
12.0–13.5 (40)
11.3 ± 0.3
10.8–11.8 (40)
7.9 ± 0.3
7.4–8.7 (40)
6.0 ± 0.2
5.6–6.4 (40)
4.4 ± 0.1
4.1–4.6 (40)
9.6 ± 0.5
8.5–10.5 (39)
4.8 ± 0.3
3.9–5.4 (40)
9.3 ± 0.4
8.4–10.1 (40)
5.0 ± 0.3
4.3–5.8 (40)
7.5 ± 0.5
6.6–8.5 (40)
5.6 ± 0.3
4.7–6.3 (40)
5.2 ± 0.1
4.9–5.5 (40)
2.8 ± 0.1
2.5–3.2 (40)
4.4 ± 0.1
4.2–4.7 (39)
4.14 ± 0.10
3.83–4.39 (44)
1.25 ± 0.04
1.17–1.34 (44)
1.43 ± 0.11
1.17–1.64 (41)
HBL
TL
HFL
EAR
WT
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
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SYSTEMATICS OF PRAOMYS
439
Table 6. Sex, age, and measurements of type specimens of the Praomys delectorum complex (Y, A, and O = young, full,
or old adult class, respectively; variable abbreviations are defined in Material and Methods)
delectorum
taitae
octomastis
melanotus
Variable
BMNH
10.9.21.3
USNM
181797
AMNH
55718
MCZ
26287
Sex
Age
TOTL
HBL
TL
HFL
EAR
ONL
ZB
BBC
DBC
BOC
IOB
LR
BR
PPL
LBP
LD
LIF
BBP
BZP
LAB
CLM
WM1
DI
F
Y
–
93
120
23
20.5
27.2
11.9
11.8
8.6
6.2
4.5
9.0
4.4
8.9
4.5
6.7
5.6
5.1
2.7
4.6
4.31
1.28
1.28
M
O
–
105
138
23
19
28.5
13.1
11.6
8.0
6.0
4.3
9.9
4.9
9.6
4.9
7.9
6.2
5.4
3.1
4.6
4.18
1.28
1.47
F
A
240
–
130
22
–
29.1
12.7
11.2
7.9
6.4
4.5
9.8
4.7
9.8
5.2
7.8
5.5
5.4
3.3
4.6
4.18
1.26
1.47
M
A
–
120
120
25
25
28.8
13.4
11.6
8.1
6.1
4.7
9.8
4.6
9.2
5.1
8.1
5.7
5.6
3.4
4.7
4.39
1.34
1.29
obscures the dark grey bases (Fig. 8A), conveying an
overall impression that Thomas (1910: 430) described
as ‘soiled buffy’. This chromatic trait drew the attention of early taxonomists who deliberated the status of
Praomys populations in northern (melanotus) and
southern (delectorum) Malawi (Lawrence & Loveridge,
1953; Hanney, 1965) and generally serves to distinguish skins of P. delectorum from those of P. melanotus
(and of P. taitae), which typically possess greyish-white
bellies (Fig. 8). Although about half of P. delectorum
skins in the Mulanje series display the pronounced
buffy overwash, not all of them do, nor is the effect
characteristic of the small samples from the Cholo Mts
and Mt Zomba. We stress that the pelage distinctions
described here and in the other species accounts are
average impressions derived from examination of large
series of specimens; variation around these chromatic
themes is substantial. Critical identification must
involve simultaneous examination of skulls.
In a report on Malawi mammals, Lawrence (in
Lawrence & Loveridge, 1953: 45) captured the essential contrasts between the skulls of P. delectorum and
P. melanotus: ‘Cranially our topotypes show that delectorum may be distinguished from melanotus by having
the width across the tooth rows less in proportion to
the length of the tooth row, the individual teeth
somewhat smaller, and the zygomatic plate narrower’.
Her observations anticipated the large loadings of
those key variables that contributed to morphometric
discrimination between samples of delectorum and
melanotus (BBP, BZP, CLM, WM1; Table 2) and that
form the nucleus of the emended diagnosis. Examples
of P. delectorum possess larger skulls than those of
P. taitae as indicated by most measurements (Table 5)
and by the disposition of sample centroids along the
first canonical variate (Fig. 4B); however, the zygomatic plate of P. delectorum is narrower and its incisors more delicate compared with samples of P. taitae
(Table 5; also emphasized by negative coefficients for
those variables on CV 2, Table 4).
Remarks: Like many other African rat-like rodents
named around the turn of the century, delectorum
was described by Thomas (1910) within Epimys, a
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
440
M. D. CARLETON and W. T. STANLEY
genus-group taxon later synonymized under Rattus.
Shortly afterwards, Thomas (1915) began to sort out
the taxonomic confusion associated with Eurasian
Rattus and to highlight the unique diversity of the
African rodent fauna when he named Praomys (as a
subgenus of Epimys); he later (1926) emended its
diagnosis as genus, including delectorum as a constituent species. In his usual spare description,
Thomas based delectorum on a single specimen
(BMNH 10.9.21.3), which he characterized (1910:
430–431) as ‘A small soft-furred species, something
like E. [ = Praomys] morio’ and ‘most nearly related
to E. [ = Praomys] tullbergi of W. Africa and E.
[ = Hylomyscus] denniae of Ruwenzori; but in any
case the relationship is very distant’. He drew attention to the well-developed t3 on the M1 of his single
specimen but withheld opinion on the trait’s stability
and taxonomic value pending acquisition of additional
specimens. Development of the t3 has figured prominently in the subsequent alpha taxonomy of Praomys,
resulting, together with synthesis of other morphological differences, in the eventual circumscription of
P. delectorum and P. jacksoni as species groups distinct from the P. tullbergi complex (Lawrence & Loveridge, 1953; Lecompte et al., 2002a; Van der
Straeten, 2008). Although we did not personally
examine the holotype of delectorum Thomas (1910),
the ample material collected by AMNH, FMNH, and
MCZ personnel from Mount Mulanje, supplemented
by the digital photographs of the holotype provided by
Paula Jenkins (BMNH), bolsters our confidence in the
application of this name to populations in southern
Malawi (also see above discussion under Results of
DFA).
The distribution that Misonne (1974) outlined for a
monotypic P. delectorum actually includes localities in
Tanzania and Kenya that others had identified as
melanotus or taitae, and as we do herein. Surely, the
listing of melanotus, octomastis, and taitae as synonyms of P. jacksoni represents a lapsus by Misonne,
whose enumeration of locality records under P. delectorum signalled his intention to allocate those three
taxa to P. delectorum following Davis (1965), a work
familiar to Misonne.
Based on specimens we examined, the distribution
of P. delectorum is confined to the Mulanje Massif and
outlying highlands (Cholo Mts, Mt Zomba) in
southern Malawi. The species may be expected in
highlands in northern Mozambique immediately
contiguous to the Mulanje region; Smithers & Lobão
Tello (1976) listed the species as probably occurring in
the country. However, it doubtfully occurs south of the
Zambezi River, an important biogeographical divide
between mammalian faunas of eastern and southern
Africa; e.g. P. delectorum has not been recorded for
the Southern African Subregion (Rautenbach, 1978;
Smithers, 1983). On the other hand, northern distributional limits of P. delectorum remain uncertain.
The species may be sought in mountains of central
Malawi, such as the Viphya ranges, where stands of
moist forest occur.
Natural history notes: Praomys delectorum s.s. has
been characterized as a terrestrial, nocturnal rodent
that principally inhabits montane forest, both
primary and regenerating forest associations
(Hanney, 1965; Ansell & Dowsett, 1988). A faunal
survey of Mt Mulanje, Malawi, conducted by W.T.S. in
July–August 2004, using the same techniques
employed in recent surveys of Praomys in Tanzania,
underlined the preference of P. delectorum for moist
montane forest. Samples of the species were obtained
in all forested habitats ranging from 1000 to 1840 m,
including two sites in submontane forest, at 1000 and
1500 m, and one at 1840 m on the Lichenya Plateau,
where forests of the Mulanje cedar (Widdringtonia
nodiflora) occurred. Happold & Happold (1989) found
Praomys to be much more common in forested sites on
the Lichenya Plateau than in neighbouring grasslands, and the 2004 survey yielded similar results. In
all three elevational settings, P. delectorum was the
most abundant rodent captured, making up 72, 69
and 60% of the rodents collected at the 1000-, 1500-,
and 1840-m sites, respectively. Other rodent genera
collected in the same traplines included Dendromus,
Lophuromys, Dasymys, Grammomys, Mus, Rattus,
Otomys and Graphiurus. Although not collected in the
2004 inventory, Beamys major is also known from Mt
Mulanje.
Only two of 22 (9%) females examined in July and
August of 2004 were pregnant; both were captured at
1575 m. One specimen had four embryos, the largest
of which had a crown–rump length of 4 mm, two
implanted in each uterine horn; the other female also
had four embryos, the largest of which was 6 mm,
distributed as three in the left and one in the right
uterine horn. Of the males examined, 86% had convoluted epididymides (N = 22); average testis length
and width was 10.8 by 6.7 mm (N = 24).
Specimens examined (96, as follows): MALAWI: Cholo
Mts (AMNH 162408–162412); Zomba (AMNH
162377–162385); Mulanje District, Mt Mulanje,
Lichenya Hut, 1840 m (FMNH 181195–181208,
181210–181214); Lichenya Plateau, 6000 ft (MCZ
44021–44030); Mt Mulanje, edge of Lujeri Tea Estate
and Mulanje Forest Reserve, next to Ruo River,
1000 m (FMNH 181216–181220, 181222–181224,
181226–181228, 181230–181232); Chisongeli Forest,
1575 m (FMNH 181234, 181237–181239, 181241,
181243–181245, 181248–181253, 181255); Mulanje
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
441
Praomys jacksoni delectorum, Lawrence & Loveridge, 1953: 44 (part, provisional allocation of series
from northern Malawi).
Rattus (Praomys) morio melanotus, Ansell, 1957:
546 (name combination, retention as valid
subspecies).
Praomys delectorum, Davis, 1965: 131 (allocated as
synonym without indication of rank).
Praomys jacksoni, Misonne, 1974: 27 (allocated as
synonym without indication of rank).
Praomys delectorum subsp., Ansell & Dowsett,
1988: 116 (part, provisional allocation of series from
northern Malawi).
Emended diagnosis: A species of the Praomys delectorum group characterized by large size (Table 5) and
robust molars (CLM usually ⱖ 4.25); zygomatic plate
broader (BZP ª 3.2–3.4 mm), dorsal notch clearly
deeper in dorsal view; pelage and epidermal surfaces
dark in tone.
Figure 9. Examples of the Praomys delectorum group as
photographed in the field: Top, P. melanotus from Ngozi
Crater in the Poroto Mountains, Southern Highlands;
Bottom, P. taitae from Mount Malundwe, central Eastern
Arc Mountains. Darker pigmentation of the epidermal
surfaces is typical of individual P. melanotus compared
with P. taitae; also note the extension of dark hairs onto
the metatarsum as characteristic of P. melanotus versus a
wholly white metatarsum and phalanges in most P. taitae.
Hindfoot length averages about 23–25 mm; photographs
by W. T. Stanley.
(MCZ 17863); Mulanje Plateau, 5500 ft (AMNH
162386–162407; BMNH 10.9.21.3).
PRAOMYS MELANOTUS G. M. ALLEN & LOVERIDGE,
1933, NEW RANK (FIGS 6–9; TABLES 5, 6)
Praomys tullbergi melanotus G. M. Allen & Loveridge, 1933: 106; type locality – ‘Nyamwanga, Poroto
Mountains, northwest end of Lake Nyasa, Tanganyika Territory’ [Tanzania]; type specimen – MCZ
26287, an adult male collected 21 March 1930 by A.
Loveridge.
Praomys jacksoni melanotus, G. M. Allen, 1939: 410
(specific reallocation, retention as valid subspecies).
Rattus [(Praomys)] tullbergi melanotus, Ellerman,
1941: 208 (name combination).
Rattus [(Praomys)] jacksoni melanotus, Swynnerton
& Hayman, 1951: 316 (name combination, retention
as valid subspecies).
Distribution: Southern Highlands of south-western
Tanzania (Livingstone Mts, Poroto Mts, Mt Rungwe)
and contiguous Misuku Mts in northern Malawi
(Fig. 10); known elevation 1524–2410 m.
Morphological description and comparisons: Allen &
Loveridge (1933: 106) succinctly described the pelage
characteristics of P. melanotus in their description of
the taxon.
‘A very dark saturated race: general color above, including
muzzle to eyes, the forehead, ears and central area of the
back, dark blackish brown, many of the hairs entirely black,
others with minute subterminal ochraceous rings [bands] that
are barely noticeable; on the sides of the face and body and on
the nape, these rings [bands] are longer, producing a dull
rufous to ochraceous wash over these areas. Lower surfaces
dull grayish white, the hairs everywhere with slaty bases. The
tail, which equals the head and body in length, is blackish all
around, with narrow rings . . . The feet are very dark smoky
brown, with silvery toes’.
The more deeply saturated, somber appearance of the
upperparts of P. melanotus has been emphasized in
comparisons with P. delectorum or P. taitae (then
ranked as subspecies of P. jacksoni – Hatt, 1940;
Swynnerton & Hayman, 1951; Lawrence & Loveridge,
1953), which commonly exhibit a brighter dorsum and
sides (Figs 8, 9). The flanks of P. melanotus are nearly
as dark as the middle dorsum; whereas, in P. delectorum and P. taitae proper, the sides noticeably grade
to paler, dominated by buffy brown to russet tones.
The dark quality of P. melanotus extends to the epidermal pigmentation of the pinnae and tail, which are
dusky to nearly black compared with medium brown
in typical P. delectorum and P. taitae (Fig. 9); the
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
442
M. D. CARLETON and W. T. STANLEY
Praomys delectorum Group
P. delectorum
P. melanotus
P. taitae
KENYA
Northern
Highlands
ins
Taita
Hills
ou
nt a
= Wet Montane Forest
A
rc
M
TANZANIA
e
e Ta
ak
rn
L
n ga
ik a
ny
E
Southern
Highlands
a
s
t
Makambako
Gap
Nyika
Plateau
wi
Lake M ala
ZAMBIA
MALAWI
MOZAMBIQUE
Mulanje
Massif
Figure 10. Distributions of the three species of the Praomys delectorum group based on specimens documented herein
(see species accounts). The patchy occurrence of Praomys across this region is closely linked to equally patchy associations
of wet montane forest (areas shaded pale grey, as extracted from World Wildlife Fund Ecoregions, USGS Digital Atlas of
Africa).
underside of the tail in P. melanotus is as dark as or
only slightly paler than the dorsal surface. The underparts of P. melanotus are typically dark grey, an
impression imparted by the long, deep slate, basal
band of ventral hairs and their short white terminal
band. The bellies of P. melanotus and P. taitae overlap
in the intensity of greyness, the former tending
toward darker and the latter paler (Fig. 8). We have
not observed the strong buffy overwash on the venters
of P. melanotus skins, a trait commonly encountered
in series of P. delectorum. In P. melanotus, the dark
brown dorsal ground colour extends at least over the
tarsus and usually onto the top of the metatarsus,
forming a sharp contrast to the silvery white hairs
investing the toes. The particoloured hindfoot typical
of P. melanotus usefully distinguishes it from samples
of P. taitae, whose tarsus-metatarsus is wholly white
(Fig. 9).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
Compared with P. delectorum and P. taitae, the
skull of P. melanotus is characterized by larger size
and ample proportions, a general assertion sustained
by univariate sample statistics (Table 5) and by
results of the several multivariate analyses (see Patterns of morphometric variation). Although nearly all
dimensions statistically emphasize the larger craniodental size of P. melanotus relative to P. delectorum or
P. taitae, the distinction is less obvious when inspecting individual skulls of mixed age classes. The immediately conspicuous differences of P. melanotus are its
broader zygomatic plate (Fig. 7), as indicated by the
deeper zygomatic notch when viewed dorsally (Fig. 6),
and the robust molar rows.
Remarks: In keeping with the taxonomic conventions
of the era, Allen & Loveridge (1933) described their
darkly saturated, montane form as a subspecies of
another Praomys, in this instance P. tullbergi, a
species described from lowland tropical forest in West
Africa. Their conviction about specific relationship
was not strong, for they opined (1933: 107) that East
African forms of Praomys are ‘instead a distinct
species, jacksoni . . . having the outer cusp [ = t3] of
the first transverse lamina in the upper m1 well
developed instead of obsolete’. Although they confusingly named melanotus as a race of P. tullbergi, Allen
& Loveridge (1933) nonetheless concluded that ‘This
race is closely related to P. jacksoni . . . and the subspecies delectorum’. Their insights anticipated the
taxonomic research and revised classifications of the
middle 1900s, in which melanotus came to be allocated as a subspecies or full synonym of either P. jacksoni or P. delectorum (Allen, 1939; Swynnerton &
Hayman, 1951; Davis, 1965; Misonne, 1974). According to the traits of the Praomys delectorum species
group reviewed above, melanotus Allen & Loveridge
(1933) decidedly belongs with this complex; moreover,
our morphometric results support its validity as a
separate species.
Ansell & Dowsett (1988: 116) identified their
samples from the Misuku Mts and Nyika Plateau as
an indeterminate subspecies of Praomys delectorum
sensu lato (s.l.), citing an unpublished study by J.
Sidorowicz, who ‘found no statistical difference in
skull and external dimensions between specimens
from northeastern Zambia, the Misuku Hills, and
the Poroto Mts’. We certainly concur as specimens
we examined from two of those localities, Misuku
Mts and Poroto Mts, represent one and the same
species, P. melanotus. Actually, the problematic affinity of the Praomys from the Misuku Mts was earlier
highlighted by Lawrence (in Lawrence & Loveridge,
1953: 45), who first discerned the barely perceptible
cranial differences between the skulls of P. melano-
443
tus and P. delectorum and thought ‘the Misuku
series is intermediate towards melanotus’. We salute
her keen perceptions.
The geographical range of P. melanotus requires
refinement. Its core distribution is apparently localized to the forested highlands that envelope northern
Lake Malawi and are bounded to the north-east by
the Makambako Gap. To the north-west, no examples
of the Praomys delectorum complex have been collected on the Ufipa Plateau, western Tanzania, or
from mountains in northern Zambia. Instead, those
highlands are inhabited by another species of
Praomys, P. jacksoni, also a member of a different
species group (Ansell, 1978; Carleton & Stanley,
2005). Praomys melanotus may be reasonably
expected to occur in extreme north-eastern Zambia
and further south in Tanzania, e.g. wherever pockets
of moist montane forest occur on the Nyika Plateau
and the Viphya Mountains that stretch south of the
Plateau. Specimens identified as Praomys delectorum
s.l. have been reported for these regions (Hanney,
1962, 1965; Ansell & Ansell, 1973; Ansell, 1978;
Ansell & Dowsett, 1988; Happold & Happold, 1989),
but these determinations require confirmation from a
fresh perspective.
Natural history notes: Samples of Praomys melanotus
were collected during two surveys of the Southern
Highlands in 1998 and 2008. A faunal survey of the
south-western slopes of Mt Rungwe in August–
September 1998 recovered P. melanotus in forested
habitats from 1870 to 2410 m, the lowest and highest
elevations within the Southern Highlands sampled by
Stanley and colleagues. In 2008, P. melanotus was
vouchered in montane forests of the Madehani and
Kitulo Plateaux, Livingstone Mts, the eastern slope of
Mt Rungwe, and the inner slope of the Ngosi Crater,
Poroto Mts.
Trap success for P. melanotus (number captured/
number of trap-nights ¥ 100) ranged from 2.1 to
12.8% across all sites surveyed, but was generally
higher on Mt Rungwe (6.0–12.8%) than in either the
Poroto or Livingstone Mts (1.2–4.2%). A striking
example of this contrast was recorded in 2008 near
the village of Bujingijila, where the eastern slope of
Rungwe and the western edge of the Livingstone Mts
were sampled on the same days with equal trapping
effort. Although the two sites were about 5 km apart,
trap success for P. melanotus was 1.2% for the Livingstone site and 7.4% for the Rungwe lines. Further
study is needed to test whether this pattern holds
across time and, if so, what reasons contribute to the
apparently lower abundance of this rodent in this
area of the Livingstone Mts compared with nearby
Rungwe forests.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
444
M. D. CARLETON and W. T. STANLEY
Of 67 females inspected across all surveys in the
Southern Highlands, 12 (17.9%) were pregnant. The
crown–rump length of the embryos ranged from 2 to
20 mm with an average of 8.4 mm. The maximum
number of embryos in any uterine horn was 5. The
average length and width of the testes of 129 males
measured was 12.5 (range = 4–17) by 7.7 (2–10) mm;
a large majority, 83.7%, possessed convoluted epididymides (N = 127).
Specimens examined (121, as follows): MALAWI:
Misuku Mts, Matipa-Wilindi Ridge, 6000 ft (MCZ
44012, 44013, 44015–44020, 44244, 44250).
TANZANIA: Iringa Region, Makete District, Livingstone Mts, Madehani Forest, 2100 m (FMNH 204710,
204711, 204713, 204717, 204719, 204720, 204722,
204726, 204728); Ukinga Mts, Madehani (MCZ
26259, 26387, 26389, 26390, 26392–26394, 26411).
Mbeya Region, Rungwe District, Poroto Mts, Ngozi
Crater, 2250 m (FMNH 205286–205290, 205292,
205294, 205295, 205297, 205299, 205300–205302,
205308, 205309, 205311, 205312); Poroto Mts, Igale
(MCZ 26497); Poroto Mts, Nyamwanga (MCZ 26285–
26288, 26290, 26310, 26327); Rungwe, 5000 ft
(AMNH 81375, 81377, 81378), 5650 ft (AMNH
81376); Mt Rungwe, Ilolo (MCZ 26292, 26293, 26295–
26297); Rungwe District, Rungwe Forest Reserve, 5
km E Ilolo, 1870 m (FMNH 163627, 163630, 163631,
163633, 163635–163637, 163640, 163644, 163645,
163647–163649, 163653, 163655, 163658, 163659,
163660, 163662, 163663, 163665, 163668, 163675,
163676, 163682, 163683, 163685, 163697, 163698,
163704, 163708, 163712, 163714, 163720, 163721,
163725, 163726, 163729, 163731, 163734–163738);
Rungwe District, Rungwe Forest Reserve, 7 km E and
2.5 km N Ilolo, 2410 m (FMNH 163740–163749,
163751–163756).
PRAOMYS
(HELLER, 1912) (FIGS 6–9;
TABLES 5, 6)
TAITAE
Epimys taitae Heller, 1912: 9; type locality – ‘Mt.
Mbololo, Taita Mountains [Taita Hills], British East
Africa [Kenya], 5000 feet altitude’ [1524 m]; type
specimen – USNM 181797, an old adult male collected 5 November 1911 by E. Heller.
Rattus [(Praomys)] taitae, Hollister, 1919: 79 (name
combination).
Rattus (Praomys) delectorum, Allen & Loveridge,
1927: 435 (part, provisional identification of series
from the Ululguru Mts, Tanzania).
Praomys taitae, G. M. Allen, 1939: 410 (name
combination).
Praomys jacksoni octomastis Hatt, 1940: 2; type
locality – ‘6000 feet [1829 m] in the Old Mbulu
Reserve [Kainam], Tanganyika Territory’ [Tanzania];
type specimen – AMNH 55718, an adult female collected 28 November 1928 by A. L. Moses.
Rattus [(Praomys)] jacksoni octomastis, Swynnerton & Hayman, 1951: 316 (name combination, retention as valid subspecies).
Praomys delectorum, Davis, 1965: 131 (octomastis
and taitae allocated as synonyms without indication
of rank).
Praomys jacksoni, Misonne, 1974: 27 (octomastis
and taitae allocated as synonyms without indication
of rank).
Praomys (Hylomyscus) denniae anselli, Bishop,
1979: 528 (part, misidentification of series from Ngorongoro, Tanzania).
Emended diagnosis: A species of the Praomys delectorum group characterized by small size (Table 5),
delicate molars (CLM ª 4.0–4.2 mm), and relatively
heavy incisors; tops of hind feet whitish, lacking
dusky swath across metatarsum.
Distribution: Chyulu Hills and Taita Hills of southern
Kenya, through the Northern Highlands and Eastern
Arc Mountains of northern and central Tanzania, as
far south as the western Udzungwa Mts (Fig. 10);
known elevation 230–2895 m, the majority of locality
records falling between 1000 and 2000 m.
Morphological description and comparisons: Heller’s
(1912: 9) characterization of the pelage of P. taitae
was brief: ‘Dorsal area russet, darkest medially; sides
lighter cinnamon, and sharply contrasted with light
underparts; ears and tail broccoli-brown; feet white;
underparts whitish, with a cream-buff suffusion; the
hairs plumbeous basally’. His chromatic synopsis
captures the reddish-brown colours and brighter
tone that dominate the pelage in samples of P. taitae,
especially compared with those of P. melanotus
(Figs 8A–C, 9). Some shade of reddish brown covers
the crown, back, and rump, tending toward fuscous
brown or umber over the middle dorsum and grading
to cinnamon or fulvous brown on the cheeks and
flanks. The junction of the dorsal–ventral pelage is
sharply delineated, without any ochraceous lateral
line. Relatively long terminal bands of white or cream
partially obscure the lead-grey bases of the ventral
hairs, imparting a medium grey to greyish white
appearance to the underparts; patches of entirely
white hairs occur over the throat and chest in some
specimens. Series of P. taitae lack the strong overwash of pinkish-buff that commonly embellishes the
underparts of P. delectorum; compared with series of
P. melanotus, the long white tips of ventral hairs give
a brighter tone to the grey underparts of P. taitae
(Fig. 8A′–C′). Tops of hind feet of P. taitae are uniformly white to dirty white, from the ankles to the
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
tips of toes, standing apart visually from the brown
dorsal pelage; this trait usefully contasts with the pes
of P. delectorum and P. melanotus, both of which commonly possess a swath of dusky hairs that extend
over the tarsus onto the metatarsus (Fig. 9).
Overall small size is the defining quality of P. taitae
among the three species of the P. delectorum group.
Its diminuitive size and delicate proportions are
attested by the univariate statistics for many variables (Table 5) and by variable loading coefficients in
the multivariate analyses (Tables 3, 4). Size contrast,
unrelated to age, is easily appreciated between
samples of the smaller P. taitae and larger P. melanotus (Fig. 6), but discrimination is less evident between
those of P. taitae and P. delectorum. Their cranial differentiation rests upon the narrower zygomatic plate,
larger molars, and finely built incisors in P. delectorum compared with relatively broader zygomatic
plate, dainty molars, and stout incisors in P. taitae
(Fig. 7).
Remarks: Like Thomas’ (1910) description of Epimys
delectorum, Heller (1912: 9) placed his new species,
the ‘Taita Forest Mouse,’ within Epimys. Heller (1912:
9) contrasted taitae only with the geographically
nearby form peromyscus (Heller, 1909) – ‘much
smaller in size, with shorter ears; skull differs decidedly in lacking beads to interorbital edges, which are
rounded, and in the shorter palatal foramina, which
reach only anterior edge of first molar’ – the latter
currently treated as a synonym of Praomys jacksoni
(e.g. Musser & Carleton, 2005). Such trenchant differences served to easily diagnose taitae as distinct
from the very different P. jacksoni (peromyscus), but
Heller’s description evidenced no awareness of
Epimys delectorum Thomas (1910), then recently
described from southern Malawi. Later authors would
associate taitae as a syononym of P. delectorum
(Davis, 1965; Musser & Carleton, 1993), and our
morphometric evidence indicates its status as a
species within the P. delectorum group.
Hatt (1940) considered his new subspecies octomastis to be a distinctive regional form of Praomys jacksoni. At the time (i.e. Allen, 1939), the construct of
P. jacksoni was broadly defined to include populations
and taxa that subsequent authors have segregated as
P. delectorum. As reflected in his choice of the specific
epithet octomastis, Hatt (1940: 2) emphasized the
mammary formula (2 + 2 = 8) as the ‘only noteworthy
point of divergence from surrounding subspecies’.
Surrounding subspecies in this case were populations
of P. jacksoni peromyscus, which Hatt recognized as
possessing only three pairs of mammae (1 + 2 = 6).
Hatt (1940: 2) was aware of the description of melanotus by Allen & Loveridge (1933) – octomastis
differs from jacksoni melanotus in ‘its generally
445
lighter colour, particularly marked on the under
surface’ – but he curiously overlooked their mention
(1933: 107) of a nursing female with ‘four pairs of
nipples’. All three females of the five specimens
forming the type series of octomastis, including the
type itself (AMNH 55718), do exhibit eight prominent
mammary glands, but we also have verified this count
on numerous females within series of P. delectorum,
P. melanotus, and P. taitae. The trait is appropriately
considered a characteristic of the P. delectorum
species group, a contrast that distinguishes it from
most members of the P. jacksoni group (Lecompte
et al., 2002a; P. degraaffi also possesses eight teats –
Van der Straeten & Kerbis Peterhans, 1999).
Nor did Hatt’s (1940) description of octomastis
address Heller’s (1912) taitae, a geographically closer
form and one whose morphology essentially resembles
octomastis. The type specimen of octomastis (AMNH
55718) agrees closely with that of taitae (USNM
181797) in most craniodental measurements (Table 6)
and nests comfortably within the variation observed
for P. taitae, as attested by the mathematical certainty of its a posteriori classification with taitae in
DFA (Fig. 4C). The two types exhibit the core qualitative traits of the P. delectorum group – interorbital
morphology, supraotic fenestration, long incisive
foramina, and pronounced t3 on M1; moreover, the
type series of octomastis conforms to the subtle diagnostic traits of P. taitae, notably the wholly white
metatarsum, intermediately sized zygomatic plate,
smaller molars, and comparatively robust incisors.
As we alluded to above, Allen & Loveridge’s (1933)
initial assignment of the Kigogo specimen (MCZ
26498), a juvenile from the Udzungwa Mts, EAM, to
melanotus was a dubious allocation. Series from the
Udzungwa Mts available to us (see Specimens examined) morphologically fit with other populations in the
EAM, the senior name for which is Heller’s (1912)
taitae. Although a juvenile, measurements of the
unworn molars of MCZ 26498 (CLM = 4.17 mm,
WM1 = 1.24 mm) fall at the lowest limits recorded for
P. melanotus but within the midrange of values
obtained for P. taitae (Table 5). We regard this past
record of melanotus from the EAM as an initial
misidentification.
Bishop (1979) allocated specimens from Ngorongoro
to the type series of his new subspecies Hylomyscus
denniae anselli. Those that we have examined
(BMNH 65.3612–65.3617) prove to be examples of
Praomys taitae as indicated by their size, long
rostrum and relatively narrow braincase, broad zygomatic plate with deep notch, and well-defined t3 and
t9 on the M1.
Although the taxa delectorum, melanotus, and octomastis eventually became associated as geographical
representatives of a widely distributed P. jacksoni
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
446
M. D. CARLETON and W. T. STANLEY
(Allen, 1939; Swynnerton & Hayman, 1951; Misonne,
1974), the small Praomys named from the Taita Hills
was regularly maintained as a species over this
period (Hollister, 1919; Allen, 1939; Allen & Loveridge, 1942; Swynnerton & Hayman, 1951). Within
Tanzania, Swynnerton & Hayman (1951) assigned
specimens from the Usambara and Uluguru Mts in
the eastern EAM to Rattus taitae, which they maintained as distinct from R. jacksoni melanotus. With
reallocation of the populations from the Udzungwa
Mts to P. taitae, contra Allen & Loveridge (1933) and
Swynnerton & Hayman (1951), the southern distributional occurrence of P. taitae is now well documented, approximately delimited by the Makambako
Gap (Fig. 10). The northern extent of its range is less
clear. While the species certainly occurs in the Northern Highlands of Tanzania, we have not found
P. taitae in the Gregorian Rift mountains of central
Kenya (Mau Escarpment, Aberdare Mts, Mt Kenya),
at least in North American collections. Search of other
natural history collections is recommended to clarify
whether it inhabits those Kenyan highlands.
Natural history notes: Samples of Praomys taitae are
generally found in submontane, montane, and upper
montane habitats (sensu Lovett, 1993b), but have
been documented as low as 230 m in the Kwamgumi
Forest Reserve, in lowland forest at the base of the
East Usambara Mountains (Stanley et al., 2005b).
The abundance of this species at this elevation (as
measured by trap success) was low relative to sites in
the same mountain range at higher elevations
(Stanley & Goodman, 2011). The Udzungwa Scarp
Forest Reserve, Udzungwa Mts, contains undisturbed
forest that ranges from 300 to 2000 m, one of the last
natural and continuous elevational gradients that can
be sampled in the Eastern Arc Mountains. Praomys
taitae (reported as P. delectorum) was recorded from
600 to 2000 m, but in abundance greater than
expected at 1460 m; none of the other elevations (600,
910 and 2000 m) yielded numbers of P. taitae greater
than expected (Stanley & Hutterer, 2007). Notably,
P. taitae was not found during a survey of the same
forest at 300 m of this escarpment a year earlier (W.
T. Stanley, unpubl. data). The highest elevation where
P. taitae has been documented is 2900 m in forested
habitats on Mt Kilimanjaro. Significantly, this species
was not observed above the tree line during a faunal
survey of this mountain (W. T. Stanley, unpubl. data).
Thus, P. taitae is restricted to forests, but ranges
lower in elevation than Hylomyscus arcimontensis,
with which it is commonly sympatric.
Praomys taitae shares its habitat with several other
rodent species. Based on intensive faunal surveys
over the past two decades, three species have been
recorded in every montane setting where P. taitae has
been recorded: Lophuromys aquilus, Grammomys
ibeanus, and Graphiurus murinus. Other species
found with P. taitae in the Eastern Arc Mountains are
Beamys hindei and Hylomyscus arcimontensis. The
latter two rodents are unknown from the northern
highland massifs. The calls for critical systematic
evaluation of the various isolated populations of
Grammomys ibeanus and Graphiurus murinus in
East African mountains (Holden, 2005; Musser &
Carleton, 2005) advise caution about sympatry among
various species until such revisionary studies are
conducted.
Data collected over three dry season surveys in the
Usambara Mountains indicate that populations of
P. taitae have limited reproductive activity between
July and September. Only 13.5% of females examined
(N = 74) were pregnant and only one in 44 (2.3%)
females assessed was lactating (Stanley & Goodman,
2011). Between 2004 and 2006, Makundi, Massawe &
Mulungu (2006) found a significant density increase
in P. taitae (reported as P. delectorum) in the
Magamba Forest, West Usambara Mts, in March–
June compared with September–December. The
greatest number of scrotal testes and perforate
vaginas were scored from the period April to June.
Based on these data, little reproductive activity
occurs during the dry period (July–August) and
P. taitae apparently breeds annually within a relatively short period. This conclusion is also borne out
by data collected during surveys of other Eastern Arc
and northern highland populations conducted every
year since 1993. In 251 females examined during
these collective surveys, only 31 (12.3%) were pregnant. A notable exception is the sample of nine specimens examined in 1996 in the Uluguru Mountains
where five (55%) were pregnant. The number of
embryos averaged 4.0 (N = 31, range 3–6), the
embryos in a single uterine horn ranging from 1 to 6.
The embryos averaged 10.5 mm in crown–rump
length (range = 2–24 mm, N = 20).
Unlike the scansorial proclivities of Hylomyscus
arcimontensis, individuals of Praomys taitae are typically captured in traps set on the ground or in other
terrestrial settings, such as on rocks or on logs easily
reachable from the ground. Arboreal traps set by
Stanley and colleagues commonly caught examples of
Hylomyscus arcimontensis, but not those of Praomys
taitae. Kingdon (1974) stated that P. jacksoni is partially arboreal.
Specimens examined (365, as follows): KENYA: Nairobi
area, Chyulu Hills, 6000 ft (USNM 344947); Coast
Region, Taita Hills, Mt Mbololo, Summit, 5000 ft
(FMNH 43458–43460; MCZ 32124, 32125, 32131;
USNM 181797, 183411–183420, 183422–183426,
183429–183432, 184508–184524, 184525); Taita Hills,
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
Mt Umengo, Summit (USNM 183433–183441); Taita
District, Taita Hills, Ngangao Forest, 4.25 km N and
1.75 km W Wundanyi, 1700 m (CM 102635–102643,
102645–102647, 102649–102652).
TANZANIA: Arusha Region, Arumeru District,
Arusha National Park, Mount Meru, 2300 m (FMNH
208574–208580, 208583–208585, 208595–208597,
208599, 208601, 208607, 208611, 208612, 208615,
208619); Ngorongoro North, 7500 ft (BMNH 65.3612–
65.3617); Old Mbulu Reserve, 5500 ft (AMNH 55702),
6000 ft (AMNH 55715–55718). Dodoma Region,
Mpwapwa District, Rubeho Mts, Mwofwomero Forest
Reserve, 1923 m (FMNH 197908–197911, 197916,
197918, 197919–197924, 197926, 197927, 197929,
197930, 197934); Mpwapwa District, Rubeho Mts,
Mwofwomero Forest, near Chugu Peak, 1900 m
(FMNH 197943, 197945, 197950–197952, 197955).
Iringa Region, Iringa District, Udzungwa Mts, Ndundulu Forest, 9 km E Udekwa, 1900 m (FMNH 177709,
177711–177715, 177717, 177719, 177720). Kilimanjaro Region, Moshi District, Mt Kilimanjaro, Kilimanjaro National Park, 7 km N and 2.5 km W Maua, 8100
ft (FMNH 173881, 174269–174271, 174273–174283);
Moshi District, Mt Kilimanjaro, Kilimanjaro National
Park, 10.5 km N and 3.5 km W Maua, 9500 ft (FMNH
174285, 174286); Moshi District, Mt Kilimanjaro,
4 km N and 1.5 km W Maua, 6700 ft (FMNH 174287–
174294, 174296, 174297, 174299–174309); Mwanga
District, North Pare Mts, Kindoroko Forest Reserve,
1688 m (FMNH 192692, 192696, 192697, 192701,
192704, 192705, 192709, 192711, 192719, 192721,
192722, 192728, 192730, 192733, 192734); Mwanga
District, North Pare Mts, Minja Forest Reserve,
1572 m (FMNH 192737, 192738, 192741, 192743,
192744, 192748, 192749, 192750, 192752, 192755,
192762–192764, 192769, 192773); Same District,
South Pare Mts, Chome Forest Reserve, 7 km (by air)
S Bombo, 1100 m (FMNH 151311, 151312, 151320,
151335, 151336, 151338, 151339, 151344, 151348,
151349, 151351, 151360); Same District (FMNH
153972–153974, 153976–153987, 153993, 153996).
Morogoro Region, Udzungwa Mts, Kigoro (MCZ
26498); Kilombero District, Udzungwa Mts, 3.5 km W
and 1.7 km N Chita, along Chita-Ihimbo trail, 910 m
(FMNH 155466, 155467, 155625, 155627, 155630);
Kilombero District, Udzungwa Mts, 4.5 km W Chita,
along Chita-Ihimbo trail, 600 m (FMNH 155478,
155653); Kilombero District, Udzungwa Mts, 19.5 km
N and 0.5 km W Chita, 2000 m (FMNH 155480,
155654,
155658–155660);
Kilombero
District,
Udzungwa Mts, 4 km W and 5 km N Chita, along
Chita-Ihimbo trail, 1460 m (FMNH 155631, 155637–
155647, 155649, 155651, 155652); Kilosa District,
Malundwe Mts, Mikumi National Forest, 985 m
(FMNH 187296–187301, 187303–187311, 187313–
187318); Kilosa District, Rubeho Mts, Ilole Forest,
447
1878 m (FMNH 197956, 197957, 197960–197964);
Kilosa District, Ukaguru Mts, Mamiwa-Kisara
Forest, 1.5 km S Mt Munyera, 1840 m (FMNH
166687, 166688, 166944, 166946–166949, 166951,
166952, 166954, 166956, 166957, 166959); Kilosa District, Ukaguru Mts, Mamiwa-Kisara Forest, 1 km E
and 0.75 km S Mt Munyera, 1900 m (FMNH 166685,
166960–166962, 166965, 166966, 166968); Morogoro
District, Nguru Mts, Manyangu Forest Reserve, 8 km
N and 3 km W Mhonda, 1000 m (FMNH 161281,
161282, 161284–161286, 161289, 161291, 161294–
161297); Morogoro District, Nguru Mts, Nguru South
Forest Reserve, 6 km N and 6 km W Mhonda, 1500 m
(FMNH 161301–161305, 161307, 161310); Morogoro
District, Uluguru Mts, Uluguru North Forest, 3 km W
and 1.3 km N Tegetero, 1345 m (FMNH 158366,
158368, 158370, 158371, 158373–158375); Morogoro
District, Uluguru Mts, Uluguru North Forest, 5.1 km
W and 2.3 km N Tegetero, 1535 m (FMNH 158379–
158381, 158384–158386, 158388, 158563, 158574);
Uluguru Mts, Bagilo (MCZ 22504, 22506); Uluguru
Mts, Vituri (MCZ 22509, 22512, 22513). Tanga
Region, Hadeni District, Nguu Mts, Nguru North
Forest Reserve, 5.6 km S and 3 km E Gombero,
1180 m (FMNH 168350, 168354, 168355, 168357,
168358, 168365, 168366, 168368, 168370, 168373,
168374, 168376, 168377, 168379, 168383, 168384,
168386, 163387, 168393, 168394, 168396, 168399–
168401); Hadeni District, Nguu Mts, Nguru North
Forest Reserve, 3.6 km S and 4.7 km E Gombero,
1430 m (FMNH 168402, 168406, 168408, 168412,
168413, 168416); Korogwe Distrtict, West Usambara
Mts, 12.5 km NW Korogwe, Ambangulu Tea Estate,
1300 m (FMNH 147309, 147311, 147313, 147317–
147320, 147327, 147332, 150158, 150280, 150281,
150283–150290, 150352–150354, 151272, 151275,
151513, 151514); West Usambara Mts, 11 km NW
Korogwe, Ambangulu Tea Estate, 1120 m (FMNH
147335); West Usambara Mts, Sunga, 35 mi N
Lushoto at Resthouse (USNM 340787); Muheza District, East Usambara Mts, 6 km NW Amani, Monga
Tea Estate, 1100 m (FMNH 150217, 150218, 150221,
150294, 150297, 150307, 150311); Muheza District,
East Usambara Mts, 4.5 km WNW Amani, Monga Tea
Estate, control site, 1100 m (FMNH 150236, 150240,
150245, 150250, 150319, 150324, 151280, 151298,
151300); Muheza District, East Usambara Mts, 8 km
WNW Amani, Bulwa Tea Estate, 1000 m (FMNH
150257, 150332, 150337); Muheza District, East
Usambara Mts, 4.5 km ESE Amani, Monga Tea
Estate, control site, 900 m (FMNH 150262, 150268,
150274, 150279, 150339, 150346, 150349, 151305–
151307); Muheza District, Kwamgumi Forest
Reserve, 4.4 km W Mt Mhinduro, 2 km S Kwamtili
Estate offices, 230 m (FMNH 153998); Magrotto Mt,
Magrotto Estate (MCZ 39057).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
448
M. D. CARLETON and W. T. STANLEY
DISCUSSION
TAXONOMIC AND BIOGEOGRAPHICAL PROSPECTUS
In retrospect, the appreciation of delectorum Thomas
(1910) as a valid species has been confounded by its
long-standing taxonomic confusion with P. jacksoni or
P. tullbergi, forms now understood to be only distantly
related to P. delectorum and to represent different
species groups within Praomys (Van der Straeten &
Dudu, 1990; Lecompte et al., 2002a, b; Lecompte,
Denys & Granjon, 2005). Although Thomas (1926)
had maintained all three as separate species when he
amended the diagnosis, rank, and contents of
Praomys, the pervasive influence of the biological
species concept over the prosecution of systematic
revision in the middle 1900s soon returned delectorum to obscurity as a subspecies or full synonym of
jacksoni or tullbergi (Allen, 1939; Ellerman, 1941;
Swynnerton & Hayman, 1951; Lawrence & Loveridge,
1953). Measured by the characters and analytical
tools consulted today, the protracted failure of systematists to discriminate P. delectorum from P. jacksoni and P. tullbergi is difficult to comprehend:
morphological recognition of the three is self evident,
as clearcut as sorting apples and oranges, complemented by equally definitive evidence of genetic divergence (Lecompte et al., 2005; Nicolas et al., 2005,
2008, 2010; Kennis et al., 2011).
An important landmark in redirecting the taxonomic dialogue was provided by Davis (1965), who
resurrected P. delectorum Thomas (1910) as a valid
species, listed characters to support his action, and
consolidated its probable synonyms. His contribution
supplied the proper taxonomic and geographical contexts to meaningfully evaluate differentiation among
delectorum-like populations, here interpreted to
support three species within the Praomys delectorum
species group: P. delectorum (Thomas, 1910); P. melanotus Allen & Loveridge (1933); and P. taitae (Heller,
1912, including octomastis Hatt, 1940). Certainly,
craniodental differences between these species,
although statistically significant in univaritate or
multivariate analyses with adequate sample sizes,
are visually inconspicuous when comparing individual skulls (Figs 6, 7). Univariate ranges overlap
considerably (Table 5) and subtle contrasts can be
appreciated only by studious examination of specimens in large series. Notwithstanding the difficulty
posed by identification of an individual Praomys skull
from any single locality, it is the pattern of differentiation discerned among samples of Praomys populations that enlightens taxonomic decisions. The three
diagnosable themes of craniodental differentiation
among these small Praomys are apparent in principal
component, discriminant function, and clustering
analyses, all of which disclose cohesive patterns of
morphological similarity congruent with major geographical discontinuities between the mountains
inhabited. The covariation patterns commonly
revealed in ordination of muroid craniodental measurements, as carefully explicated by Voss and colleagues (Voss et al., 1990; Voss & Marcus, 1992),
relate to the underlying ontogenetic trajectories that
account for such conserved patterns of size and shape
and, by inference, to pronounced genetic divergence
between the sampled populations. For several genera
of African murines, evidence of genetic divergence
indicative of specific distinctiveness generally has
accompanied the demonstration of well-delineated
morphometric footprints among populations (e.g. Verheyen et al., 2002, 2003, 2007; Nicolas et al., 2005,
2010; Kennis et al., 2011). This body of literature
encourages our interpretation that the morphometric
results sustain recognition of at least three species
within the P. delectorum complex, a hypothesis
that naturally invites complementary molecular
investigations.
While the morphometric techniques employed
herein are useful to identify species limits among
populations of the P. delectorum group, they do not
speak convincingly to the hierarchy of relationship
among those species. The pattern of craniodental
similarity, as represented in the phenogram using
Mahalanobis squared distances (Fig. 5), provides a
working hypothesis of cladistic relationship among
the three species – (P. melanotus–[P. delectorum–
P. taitae]). Nonethess, a plausible scenario can be
developed from the vicariant logic of geographical
distributions and age of mountains inhabited (see
below) to support the alternative hierarchy (P. taitae–
[P. melanotus–P. delectorum]).
Evidence to date suggests that the P. delectorum
group is most closely related to the P. jacksoni
complex among the five species groups of Praomys, a
phyletic association based on cladistic analysis of
morphological data (Lecompte et al., 2002a). This
relationship must be considered tentative, for only
one of the 40 characters defined by Lecompte et al.
(2002a) was uniquely derived for the (P. delectorum–
[P. jacksoni–P. mutoni]) clade, and this grouping was
inconsistently recovered depending on the subset of
characters they applied. The additional species recognized herein, P. melanotus and P. taitae, are essentially identical to P. delectorum with regard to the
qualitative characters employed by Lecompte et al.
(2002a). Of course, the larger issue of relationship
concerning Praomys is the monophyly of the taxon.
Whether generated from morphological or molecular
datasets, Praomys emerges as a paraphyletic or polyphyletic construction, representative members of the
various species groups not sharing a most recent
common ancestor on derived trees (Lecompte et al.,
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
3000
2500
2000
Elevation (m)
1500
1000
500
e
ita
ta
P.
us
ot
m
el
an
or
P.
le
de
P.
.a
rc
im
on
ct
te
ns
um
is
0
H
2002a, b, 2005; Kennis et al., 2011). Van der Straeten
& Kerbis Peterhans (1999) volunteered that all of the
Praomys species groups may merit separate generic
recognition in view of the singular morphological differentiation exhibited by each. We concur that the
P. delectorum group is morphologically strongly circumscribed, unique in its combination of traits compared with the other species groups, in particular the
P. jacksoni complex under which delectorum and
related taxa were so long synonymized. However, the
cladistic perspective needed to test their conjecture
will require denser species sampling within
Praomyini and incorporation of multiple genes in
molecular studies.
The distribution of members of the Praomys delectorum group tightly adheres to wet forest associations, a discontinuous habitat in south-eastern Africa
(Fig. 10). Most collecting localities fall within an
elevational belt of 1000–2400 m (Fig. 11), in moist
forest zones classified (sensu Lovett, 1993b) as Upper
Montane (> 1800 m), Montane (1200–1800 m), or Submontane (800–1200 m) and receiving ⱖ 1200 mm of
rainfall annually. Locality records of P. delectorum
and P. melanotus are mainly confined to Montane and
Upper Montane forests, but P. taitae is notable for the
extremes of its elevational range, documented from
230 m (foothills of East Usambara Mts) to 2897 m (Mt
Kilimanjaro). Compared with other ranges in the
EAM, moist forest communities in the East Usambara Mts extend to lower elevations due to their
nearness to the coast, an exposure that enhances the
orographic effects of Indian Ocean monsoonal circulation and consequent depression of forest zones
(Lovett, 1993b; Burgess, Fjeldså & Botterweg, 1998).
The highest peak in the EAM reaches only 2635 m
(Kimhandu Peak, Uluguru Mts), in contrast to the
monumental peaks attained by the Pleistocene volcanic mountains that comprise the Northern Highlands,
such as Mt Kilimanjaro, and the generally higher
elevational belts occupied by wet forest associations
on the slopes of these inland mountains.
The P. delectorum species group represents an
element of the Afromontane Biotic Region (sensu
White, 1978, 1981) in view of its ecological occurrence
and naturally patchy distribution across East Africa’s
mountainous landscape. Biogeographers have distilled avian and plant distributions and foci of species
richness to identify seven physiographic montaneforest groups within the Afromontane region (Moreau,
1966; White, 1978; Dowsett, 1986). These montane
groupings are largely equivalent among the various
disciplines but may differ slightly in exact geographical limits and in their proposed names; here, we adopt
Moreau’s (1966) terminology and definitional limits of
mountain systems. The areal range of the P. delectorum species group largely coincides with the
449
Figure 11. Plot of elevational ranges (in metres, above
sea level) of Hylomyscus arcimontensis (including localities
in the EAM and Southern Highlands) and the three
species of the Praomys delectorum species group. Vertical
line embraces the elevational range of each species and
filled circles indicate elevations of individual collecting
localities (see Appendix X).
Tanganyika–Nyasa Montane Group (including the
Taita Hills, Kenya), but it also straddles the southern
portion of the Kenya Montane Group by virtue of the
presence of P. taitae in the Northern Highlands of
Tanzania, extralimital to the EAM. In a subsequent
avifaunal study, Stuart et al. (1993) discerned a biogeographical division within the Kenya Montane
Group (Central East African Montane Forest Group
per their terminology), consisting of a north-west subgroup (Mt Elgon, Aberdare Mts, Mt Kenya), demonstrating faunal affinity to Albertine Rift birds, and a
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
450
M. D. CARLETON and W. T. STANLEY
south-east subgroup (Mt Kilimanjaro, Mt Meru, Ngorongoro Crater Highlands), having affinity with taxa in
the EAM and Southern Highlands of Tanzania
(together, the East Coast Escarpment Montane Forest
Group per their terminology). The northernmost distribution of the P. delectorum group thus fits the
latter pattern; to date, it has not been documented
from mountains in the north-west subgroup of Stuart
et al. (1993). With removal of P. delectorum and its
kin from the synonymy of P. jacksoni (Davis, 1965;
Musser & Carleton, 1993), no species of Praomys is
now known to occur in both Tanganyika–Nyasa forest
and Guineo-Congolian forests of West and Central
Africa. The closest distributional approach by a
member of another species group is P. jacksoni s.l.,
documented on the Ufipa Plateau, west-central Tanzania (W. T. Stanley, unpubl. data; Mbizi Mts, Mbizi
Forest Reserve, FMNH 171436–171447). This nearly
complete disjunction between eastern and western
forests at the species level accords with the pattern
demonstrated for certain other vertebrate groups
(Howell, 1993).
Whereas all three species of the Praomys delectorum species group conform to an Afromontane distribution, members of the other species groups within
the genus are principally lowland in occurrence,
whether inhabiting tropical rainforest of the GuineoCongolian lowlands (P. jacksoni, P. lukolelae, P. tullbergi groups) or Northern Savanna woodlands of West
Africa (P. daltoni group). Some Praomys species are
restricted to wet monane forest within both the
P. tullbergi group (Cameroun Mts – P. hartwigi,
P. morio) and the P. jacksoni group (Albertine Rift
highlands – P. degraaffi). Such exceptions, restricted
to different Afromontane regions – Cameroun
Montane Group and East Congo Montane Group,
respectively, of Moreau (1966) – suggest the independent evolution of montane-forest endemics from
lowland congeners. The derivation of the Afromontane P. delectorum species group from some GuineoCongolian progenitor may represent a third instance
of independent penetration of a montane-forest niche
within Praomys s.l. However, the common ancestry of
this Guineo-Congolian progenitor may be old and lie
outside the Praomys species groups as their contents
are currently circumscribed.
The distribution of the P. delectorum group overlays
a complex mountainous landscape, diverse in geological age and orogenic formation. The crystalline rocks
that compose the EAM are ancient (Precambrian), but
the latest episode of block-fault uplifting that
sculpted the current topography transpired primarily
in the late Miocene–Pliocene (Griffiths, 1993). The
Northern and Southern Highlands, bookends to the
EAM chain, consist of active and extinct volcanoes,
younger geological creations that date mainly to the
Pleistocene–Holocene. Biotic surveys of the dense
forests investing the eastern and south-eastern slopes
of the EAM mountains have uncovered impressive
levels of endemism for many organisms, plant and
animal, an emerging understanding that collectively
emphasizes the antiquity of these forests (see chapters in Lovett & Wasser, 1993; Burgess et al., 1998,
2007) and highlights their conservation value as a
centre of biodiversity (Myers et al., 2000; Burgess
et al., 2007). Moreover, biogeographical syntheses,
especially as phylogenetically informed by DNA
sequence data, have revealed a striking mixture of
kinship-levels among such endemics, including older,
relictual taxa along with younger, recently evolved
species (Howell, 1993; Lovett, 1993b; Fjeldså &
Lovett, 1997; Roy et al., 1997; Fjeldså & Bowie, 2008).
Against the backdrop of such provocative research,
the origination of the delectorum group, whether an
old or recent lineage in the evolutionary radiation of
Praomyini (sensu Lecompte et al., 2008), remains
unknown.
PRAOMYS
TANZANIA
MORPHOMETRIC DIFFERENTIATION OF
AND
HYLOMYSCUS
IN
Populations of the Praomys delectorum group share
their montane habitat with only one other member of
Praomyini, Hylomyscus arcimontensis. Examples of
H. arcimontensis co-occur with P. taitae at nearly all
forested sites surveyed within the EAM (H. arcimontensis not documented from the Taita Hills) and with
P. melanotus in the Southern Highlands (Stanley
et al., 1998b [reported as H. denniae]; Carleton &
Stanley, 2005; Stanley & Goodman, 2011). Although
distributions of the P. delectorum group and H. arcimontensis are broadly sympatric in Tanzania, the
latter species has not been documented from the
Northern Highlands (Carleton & Stanley, 2005), nor
has it been collected in moist forests of southern
Malawi, the range of P. delectorum s.s. (Hanney, 1965;
Ansell & Dowsett, 1988; W. T. Stanley, unpubl. data).
The patterns of craniodental differentiation evident
among populations of Praomys and Hylomyscus are
intriguing in light of the substantial congruence of
their Tanzanian distributions, both of which span the
Makambako Gap.
The following comparisons issue from DFAs of
Praomys and Hylomyscus, conducted separately as
conveyed in results reported above and those in Carleton & Stanley (2005) and based only on nine
co-distributed montane samples (see Appendix 3 for
specimens of H. arcimontensis). The amount of variation captured by the first canonical variate extracted
is greater for the nine-OTU DFA of Praomys (63.7%)
compared with that derived for samples of Hylomyscus (46.2%). A pronounced shift in CV 1 scores occurs
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
among Praomys samples, coincident with samples
obtained on either side of the Makambako Gap; mean
CV 1 scores substantially differ and ranges do not
overlap between geographical subgroups. The nine
samples of H. arcimontensis, on the other hand,
broadly overlap in CV 1 ranges, and their means
irregularly trend in a south-westerly direction from
smaller (South Pare Mts) to larger (Mt Rungwe)
animals; no abrupt shift in craniodental covariation is
apparent between population samples on either side
of the Makambako Gap (Fig. 12, top; also see Carleton & Stanley, 2005: fig. 8). For the nine montane
samples of Praomys, the last clustering cycle based on
Mahalanobis distances between group centroids
deeply divides those in the Southern Highlands (Livingstone Mts, Mt Rungwe) from those in the EAM
(South Pare Mts through the Udzungwa Mts); within
the latter cluster, the OTU representing the Ukaguru
Mts again emerges as the most strongly differentiated
Praomys within the EAM (Fig. 12, bottom; also see
Fig. 5). For examples of Hylomyscus from the same
mountain systems, the last two clustering cycles successively amalgamate those samples from the northern periphery of the EAM (South Pare Mts, West
Usambara Mts); the Hylomyscus OTUs from the
Southern Highlands (Livingstone Mts, Mt Rungwe)
do form a unique pair-group but at a much lower level
of dissimilarity (Fig. 12, bottom). As argued herein,
we recognize the pronounced craniodental divergence
between Praomys populations separated by the
Makambako Gap as demarcating separate species,
P. melanotus (Southern Highlands) and P. taitae
(EAM). Carleton & Stanley (2005) interpreted the
broadly overlapping samples of Hylomyscus as geographical variation within a single species, H. arcimontensis, including EAM localities as well as those
from south-west of the Makambako Gap.
The morphometric contrasts between Tanzanian
samples of Hylomyscus and Praomys surprised us.
Having encountered only minor differentiation among
Hylomyscus populations across the Makambako Gap
(Carleton & Stanley, 2005), we had anticipated a
similar pattern within Praomys. Indeed, the distributional records for Hylomyscus intimate that its
populations would be more likely to experience
differentiation among montane isolates. Within the
EAM, specimens of H. arcimontensis are unknown
from elevations as low as those recorded for P. taitae
(Carleton & Stanley, 2005; Stanley & Hutterer, 2007,
fig. 11): the lowest locality so far documented for
H. arcimontensis is 900 m in the East Usambara Mts;
whereas, examples of P. taitae are known from 230 m
in the East Usambara Mts and 600 m in the
Udzungwa Mts. Where collected in sympatry, populations of Praomys are more abundant, as measured by
trapping success, than Hylomyscus and seem to better
451
tolerate degraded secondary habitats (Stanley &
Goodman, 2011). Compared with Praomys, H. arcimontensis is more capably scansorial and may be
more dependent on arborescent primary habitats, as
suggested by certain morphological adaptations (relatively long, penicillate tail and short, broad hindfoot
with long fifth digit; Carleton et al., 2006), direct
observations of climbing activity (Stanley et al.,
2005a), and comparative trap success in arboreal
versus ground sets. Such considerations led us to view
populations of Praomys as more prone to dispersion
between isolated montane forests, facilitated by lowering of vegetation belts during Pleistocene fluctuations (Hamilton, 1982; Lovett, 1993a), than those of
Hylomyscus. The pronounced craniodental differentiation evident in the covariation of Praomys data,
coincident with a major geographical barrier, contradicts this expectation.
Whether patterns of morphometric differentiation
within Praomys vis à vis Hylomyscus mirror comparable levels of genetic divergence invites studies that
employ a phylogeographical approach and incorporate
several genes. Such a needed perspective will further
illuminate differentiation among Praomys populations across these mountains and the interplay of
geographical distance, isolation, and recency of diversification. We find it noteworthy that complementary
molecular and morphometric data sets of soricomorph
shrews distributed across these same Tanzanian
mountains have disclosed different topologies of area
relationship, one involving intraspecific variation
(Sylvisorex – Stanley & Olson, 2005) and the other
addressing interspecific relationship (Myosorex –
Stanley & Esselstyn, 2010); in both generic examples,
genetic similarity more closely tracked geographical
proximity among EAM units than did the morphometric data set. The praomyine genera Hylomyscus
and Praomys offer an ideal system to compare the
diversification of rodents and shrews that cohabit
Tanzania’s montane forests.
FAUNAL RESEMBLANCE PATTERNS AMONG MONTANE
SMALL MAMMALS IN
TANZANIA
The contrasting patterns disclosed between Hylomyscus and Praomys populations apropos the Makambako Gap focus attention on that discontinuity in
moist forest cover and its historical influence on
delimiting distributions of small mammal species
within Tanzania. Notions about its significance as a
vicariant barrier largely hinge upon the taxon under
study. Although we conveniently invoked the Gap in
understanding the distributional limits of Praomys
species, Stanley & Esselstyn (2010) discounted it as
an inconsequential barrier in their interpretation of
interspecific kinship among species of Myosorex. To
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
452
M. D. CARLETON and W. T. STANLEY
6
8
6
4
CV 1 (46.2%)
CV 1 (63.7%)
4
2
0
2
0
-2
-2
-4
-6
-4
SPA WUS EUS NGR UKA ULU UDZ LIV RUN
SPA WUS EUS NGR UKA ULU UDZ
LIV RUN
Tanzanian Mts
Tanzanian Mts
Praomys
Hylomyscus
South Pare Mts
W Usambara Mts
E Usambara Mts
Nguru Mts
Ukaguru Mts
Uluguru Mts
Udzungwa Mts
Makambako
Gap
Makambako
Gap
Livingstone Mts
Mt Rungwe
100
50
Mahalanobis D
0
0
75
Mahalanobis D
Figure 12. Morphometric comparisons of samples of Hylomyscus and Praomys that co-occur in montane forest across the
Eastern Arc Mountains (South Pare Mts to Udzungwa Mts) into the Southern Highlands (Livingstone Mts and Mt
Rungwe) of Tanzania. Top graphs: north–south transects of morphometric differentiation as indexed by the first canonical
variate extracted; vertical lines correspond to the sample range and filled circles to the sample mean (Abbreviations: EUS,
East Usambara Mts; LIV, Livingstone Mts; NGR, Nguru Mts; RUN, Mt Rungwe; SPA, South Pare Mts; UDZ, Udzungwa
Mts; UKA, Ukaguru Mts; ULU, Uluguru Mts; WUS, West Usambara Mts). Bottom phenograms: Cluster diagrams
(UPGMA) based on Mahalanobis squared distances between the nine OTU centroids as derived from discriminant
function analysis; only nodes that were consistently recovered by bootstrapping are indicated (ⱖ 70%, 1000 iterations),
leaving poorly defined levels of phenetic affinity as unresolved. Both multivariate perspectives document abrupt shifts in
craniodental differentiation between populations of Praomys coincident with the Makambako Gap (here interpreted as
different species, P. melanotus and P. taitae) but not those of Hylomyscus (interpreted as the single species H. arcimontensis by Carleton & Stanley, 2005). See text for discussion.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
more fully appreciate the biogeographical significance
of the Makambako Gap, we here explore broad patterns of faunal similarity among terrestrial small
mammals whose distribution coincides, entirely or
partially, with moist montane settings in Tanzania.
We compiled distributional records for 65 species of
terrestrial small mammals (orders Afrosoricida, Macroscelidea, Soricomorpha, Rodentia) from primary
revisionary and distributional literature, giving
weight to those publications that provided specific
localities and/or listed catalogue numbers, or to secondary sources that are largely based on first-hand
examination of vouchered specimens (see species and
authorities in Appendix 4). Species were individually
tallied for the 12 mountain systems of the EAM, but we
combined named mountains within the Northern and
Southern Highlands. In addition to presence/absence,
each species was generally identified as a montaneforest inhabitant (embracing Lovett’s, 1993b, Submontane, Montane, and Upper Montane subdivisions), or
not, but we acknowledge that straightforward ecological categorization can be subjective (Table 7). For
reasons of uncertainty or ambiguity about habitat in
published sources, as discussed below, we tended to err
on the side of forest inclusiveness. For a robust depiction of faunal similarity, we repeated Sørensen and
Raup–Crick calculations based on all 65 species or the
subset of 46 whose distribution we believe to be more
dependent on wet montane forest (albeit not necessarily restricted to montane forest).
The EAM collectively circumscribe greater species
diversity and more endemics of terrestrial small
mammals than found in either the Northern or the
Southern Highlands (Table 7), an assessment in
general agreement with other biological groups
(Lovett, 1993b; Stuart et al., 1993; Burgess et al.,
2007). The proportion of endemics is higher for the
Northern Highlands, however, and most of those
unique species are confined to Mt Kilimanjaro. The
EAM diversity and endemism counts of small
mammals are moderate compared with figures
recorded for mountains that flank the Albertine (East
Congo Montane Group) and Gregorian (Kenyan
Group) Rift Valleys (Carleton et al., 2006: table 8 –
their tallies are already an undercount in view of
recent taxonomic descriptions and revisions). Among
individual EAM blocks (Appendix 4), more species
(22–31) are recorded for the East and West Usambara
Mts, Uluguru Mts, and Udzungwa Mts, totals that in
part reflect the long history of biological survey in
those mountains (Allen & Loveridge, 1927, 1933;
Stanley et al., 1998a, 2005a; Stanley & Hutterer, 2007;
Stanley & Goodman, 2011). Other EAM highlands
have only recently received dedicated mammalogical
survey – such as the Malundwe, Nguu, and North Pare
Mts (Stanley, Kihaule & Munissi, 2007a, Stanley et al.,
453
2007b) – and tallies for these mountains are low
(Appendix 4). Still, the few species (4–8) recorded for
those systems may convey actually lower biodiversity
in view of the small area of montane forest that caps
their mountain tops (see Burgess et al., 2007: table 1).
Of the ten species endemic to the EAM as a whole, none
has been documented across all component mountain
systems as the geographical limits of the EAM are
defined (i.e. Wasser & Lovett, 1993); eight of the ten
endemics are restricted to wet montane forest, one to
subalpine ericaceous shrub and grasslands (Otomys
sungae), and one to riverine and palustrine habitats
(Dasymys sua). Most endemic species are locally distributed among contiguous mountains within the EAM
(e.g. Crocidura usambarae in the Pare and Usambara
Mts, or Myosorex geata in the central EAM); four
endemics are known from single mountain systems,
one each inhabiting the East Usambara and Uluguru
Mts and two the Udzungwa Mts (Appendix 4). Unlike
other vertebrate groups (Howell, 1993; Burgess et al.,
2007; Malonza, Lötters & Measey, 2010), no small
mammal species is known to be wholly restricted to the
Taita Hills, although Sylvisorex aequatorius may
qualify as endemic upon further taxonomic review. In
general, levels of endemism among terrestrial small
mammals per single EAM block are trivial compared
with that documented in other vertebrate groups,
particularly amphibians and reptiles (Rogers & Homewood, 1982; Howell, 1993; Burgess et al., 2007). The
contribution of the EAM to the diversification of
Afromontane mammals would appear greater if we
had, like Burgess et al. (1998, 2007), distinguished
‘near endemics’ (e.g. species such as Crocidura monax
and Praomys taitae known from the EAM and Northern Highlands, or Myosorex kihaulei and Otomys
uzungwensis from the Udzungwa Mts and Southern
Highlands).
Phenograms of montane associations based on
Sørensen or Raup–Crick values concord in their depiction of a core EAM group (North and South Pares, West
and East Usambaras, Nguru and Uluguru Mts); the
consistent union of the Southern Highlands with the
Udzungwa Mts, a pair-group deeply separated from
the core EAM; and the outlier disposition of the Taita
Hills and Northern Highlands (Fig. 13). The cluster
diagrams notably disagree in the disposition of certain
central EAM blocks (Malundwe, Nguu, Rubeho,
Ukaguru Mts), a cluster that is segregated from all of
the above mountains according to the Sørensen
measure of faunal similarity; the individuality of this
cluster is lost, amalgamated with the core EAM, when
using the Raup–Crick index (Fig. 13A, B vs. 13C, D).
We attribute this contrast in clustering results to the
low number of species recorded for these four mountains (4–8), their uniform possession of two broadly
distributed species (Beamys hindei, Praomys taitae),
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
454
M. D. CARLETON and W. T. STANLEY
Table 7. Occurrence of small mammal species in Tanzania’s three major mountain complexes (also see Appendix 4);
presence (X) based on vouchered museum specimens, presumed endemic species (Xe) to a single mountain complex, and
occurrence within wet montane forest (X) are indicated
Order: family
Montane
Forest
Species
Afrosoricida: Chrysochloridae
Chrysochloris stuhlmanni
Macroscelidea: Macroscelididae
Petrodromus tetradactylus
Rhynchocyon petersi
R. uzungwensis
Soricomorpha: Soricidae
Congosorex phillipsorum
Crocidura allex
C. desperata
C. elgonius
C. fuscomurina
C. hildegardeae
C. hirta
C. jacksoni
C. luna
C. monax
C. montis
C. olivieri
C. tansaniana
C. telfordi
C. usambarae
C. xantippe
Myosorex geata
M. kihaulei
M. zinki
Sylvisorex aequatorius
S. granti
S. howelli
S. megalura
Rodentia: Sciuridae
Heliosciurus mutabilis
H. undulatus
Paraxerus vexillarius
Rodentia: Gliridae
Graphiurus kelleni
Graphiurus murinus
Rodentia: Spalacidae
Tachyoryctes daemon
Rodentia: Nesomyidae
Beamys hindei
Cricetomys ansorgei
Dendromus insignis
D. mystacalis
D. nyasae
D. nyikae
Eastern Arc
Mountains
Southern
Highlands
X
X
X
X
X
X
X
Xe
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Northern
Highlands
Xe
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Xe
Xe
Xe
X
Xe
X
X
X
Xe
X
X
X
X
X
X
Xe
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Xe
X
X
X
X
X
X
X
X
X
X
X
X
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
455
Table 7. Continued
Order: family
Species
Rodentia: Muridae
Aethomys hindei
Dasymys incomptus
D. sua
Grammomys dolichurus
G. ibeanus
G. macmillani
Hylomyscus arcimontensis
Lophuromys aquilus
L. kilonzoi
L. machangui
L. makundii
L. verhageni
Mus musculoides
M. triton
Otomys lacustris
O. sungae
O. uzungwensis
O. zinki
Pelomys fallax
Praomys melanotus
P. taitae
Rhabdomys dilectus
Zelotomys hildegardeae
Rodentia: Anomaluridae
Anomalurus derbianus
Rodentia: Bathyergidae
Cryptomys hottentotus
Heliophobius argenteocinereus
Number of species
Number/percentage of endemics
Montane
Forest
X
X
X
X
X
X
X
X
X
X
Northern
Highlands
Eastern Arc
Mountains
Southern
Highlands
X
X
X
Xe
X
X
X
X
X
Xe
X
X
X
X
Xe
Xe
Xe
X
X
X
X
X
Xe
X
X
X
X
Xe
X
X
X
X
X
X
X
X
X
X
and the weight given to joint presence by the Sørensen
coefficient. This combination of factors is more strongly
emphasized by a distance coefficient like Sørensen’s
compared with the Raup–Crick index, which weighs
observed species co-occurrences against a probabilistic estimate of faunal similarity generated from
randomized sampling of the entire pool of mountain
samples.
Both measures of faunal similarity divulged basically the same structure of area relationships whether
based on all small mammal species recorded for mountainous elevations or the subset of species thought to
be principally denizens of montane forest. The phenograms based on the Sørensen coefficient are nearly
identical (Fig. 13A, B); whereas, those based on the
Raup–Crick index differ over which mountain complex
is portrayed as faunistically closer to the core EAM,
X
23
6/26.1
X
X
52
10/19.2
X
19
0/0.0
the Udzungwa Mts–Southern Highlands using all
species (Fig. 13C) versus the Taita Hills using species
found in montane forest (Fig. 13D). This general agreement bolsters our confidence that the pattern of
montane associations depicted is robust to our likely
mistakes in categorizing a species’ ecological occurrence in or dependence upon montane forest.
The pattern of faunal similarity among Tanzania’s
mountain systems, as derived using the Raup–Crick
index (Fig. 13C, D), sensibly relates mountains
according to geographical proximity, with certain
plausible exceptions, and resembles results distilled
from syntheses of other vertebrates (Stuart et al.,
1993; Fjeldså & Bowie, 2008; Menegon et al., 2011).
Avifaunal studies have identified eastern (Pares and
Usambaras), central, and western (Udzungwa Mts)
faunal units within the EAM (Stuart et al., 1993;
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
456
M. D. CARLETON and W. T. STANLEY
All Montane Habitats
Montane Forest
A
NGU
.4
.6
.8
B
NGU
UKA
UKA
RUB
RUB
MAL
MAL
TAI
TAI
NPA
NPA
SPA
SPA
WUS
WUS
EUS
EUS
NGR
NGR
ULU
ULU
UDZ
UDZ
SHI
SHI
NHI
NHI
1
Sorensen Index
1
.8
Sorensen Index
C
.2
.6
.4
D
.4
.6
Raup-Crick Index
.8
1
TAI
TAI
NPA
NPA
SPA
SPA
WUS
WUS
EUS
EUS
MAL
MAL
NGU
NGR
NGR
ULU
UKA
NGU
RUB
UKA
ULU
RUB
UDZ
UDZ
SHI
SHI
NHI
NHI
.2
.4
.6
.8
1
Raup-Crick Index
Figure 13. Interpretations of area relationship among Tanzanian mountains, as derived from documented occurrences
(Appendix 4) of terrestrial small mammals in all montane settings (A, C) or those restricted to montane forest (B, D) and
based on two measures of faunal similarity, Sørensen’s (A, B) and Raup-Crick’s (C, D) indices. Mountain abbreviations:
EUS, East Usambara Mts; MAL, Malundwe Mts; NGU, Nguu Mts; NGR, Nguru Mts; NHI, Northern Highlands (Mt
Kilimanjaro, Mt Meru, Ngorongoro Crater Highlands); NPA, North Pare Mts; RUB, Rubeho Mts; SHI, Southern
Highlands (Livingstone Mts, Poroto Mts, Mt Rungwe); SPA, South Pare Mts; TAI, Taita Hills; UDZ, Udzungwa Mts; UKA,
Ukaguru Mts; ULU, Uluguru Mts; WUS, West Usambara Mts.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
Fjeldså & Bowie, 2008); however, the composition
and linkages among subdivisions of the EAM based
on small mammals differ in detail from the avifaunal groupings, as do the bird studies from one
another. A foremost contrast involves the North and
South Pare Mts, which Stuart et al. (1993), who also
employed the Sørensen coefficient, included within
their Central East African Group; mammalian distributional data decidedly relate the Pares to the
nearby Usambaras and core EAM (Fig. 13C, D). The
Udzungwa Mts demonstrate much stronger affinity
with the Southern Highlands than with any unit of
the EAM, a consistent association reflecting the 15
species whose distribution spans the Makambako
Gap (Appendix 4). The union of the Udzungwa Mts–
Southern Highlands and their conspicuous segregation from the core EAM reinforce the possible
vicariant role of the Ruaha River, whose basin separates the Rubeho and Malundwe Mts from the
eastern Udzungwa Mts; Stanley & Esselstyn (2010)
emphasized the Ruaha River in reconstructing the
biogeographical history of Myosorex populations.
Ours is an incomplete picture of faunal associations
that involve the Southern Highlands. Certain
species (Beamys hindei, Lophuromys machangui,
Praomys melanotus) have affinity with populations
or taxa that inhabit montane forest along the southern Rift Valley, i.e. coextensive with the southern
reaches of the Tanganyika–Nyasa Montane Group of
Moreau (1966) or East Coast Escarpment Group
sensu Stuart et al. (1993); other taxa known from
the Southern Highlands (Chrysochloris stuhlmanni,
Rhabdomys dilectus) are nominally consanguineous
with populations in Albertine Rift mountains. The
Taita Hills harbour an assortment of mammals that
is strikingly differentiated from all other parts of
the EAM, perhaps reflecting longer periods of isolation and attenuation of distributions owing to the
position of the Taita Hills at the northernmost
periphery of the EAM (Fig. 1). Certain species that
are broadly distributed within the EAM – such as
Beamys hindei, Hylomyscus arcimontensis, and
Lophuromys kilonzoi – reach the Pare and Usambara Mts but are unrecorded from the nearby Taita
Hills. The Northern Highlands and its smallmammal contingent emerge as the most dissimilar
(Fig. 13C, D), with ten of 23 species recorded as
unique among the Tanzanian mountain complexes
herein considered. Of these ten, six species are
endemics, some of which are related to species
groups or genera in the Kenyan and Ethiopian
Montane Groups (e.g. Tachyoryctes daemon, Otomys
zinki); many of the non-endemics indigenous to Tanzania’s Northern Highlands appear to represent the
southern frontier of species distributionally centred
in the Kenyan and East Congo Montane Groups
457
(e.g. Crocidura allex, C. montis, Sylvisorex granti,
Dendromus insignis).
RETROSPECTIVE COMMENTS
Each of the foregoing summarial statements on
faunal patterns is weakened by the unstated qualifiers ‘as specific distributions are currently documented’ and ‘according to recent taxonomic
understanding’. Computations of faunal resemblance
implicitly presume that collecting effort, field sampling methods, and baseline distributional knowledge
are comparable when scoring presence/absence of
species. Thankfully, the empirical foundation of small
mammal distributions in the EAM and other Tanzanian highlands has benefited immeasurably from
relatively recent biological surveys instituted in the
early 1990s (e.g. see Stanley, Goodman & Newmark,
2011b, for an historical review of mammal study in
the Usambaras). More recent surveys, in particular
mountains of the Southern Highlands, are still being
analysed, and these results will undoubtedly alter the
picture of small mammal distributions and endemism. For the present example of Praomys, approximately 65% of the localities herein reported, and
about 70% of the specimens, stem from such recent
collecting activities conducted over the past 20 years
(Appendix 1), whereas some 35% of documented
localities are based on older collections obtained over
the eight decades prior to 1990, most of those within
the period 1910–1940. Clearly, robust morphometric
treatment of the Praomys delectorum group or our
admittedly preliminary views of faunal similarity
would have been impossible without the montane
samples generated from this recent bout of directed
biological survey. As is usually the case, a vastly
improved distributional foundation simultaneously
exposes our inadequate systematic understanding of
many montane forms and underlines the need for
alpha taxonomic revision. Several genera found
within the EAM (e.g. Chrysochloris, Crocidura,
Graphiurus, Beamys, Dendromus, Grammomys, Mus,
Rhabdomys) require systematic attention to reconcile
seemingly interrupted geographical occurrences with
improved definitions of specific limits (see remarks
under appropriate species accounts by Holden, 2005;
Hutterer, 2005; Musser & Carleton, 2005).
In addition to taxa in need of revision, critical
re-identification of older museum specimens would
appreciably redress apparent distributional gaps or
biogeographical erratics. For example, the records of
Hylomyscus denniae from the Ngorongoro Crater
Highlands (Bishop, 1979) and Mt Meru (Demeter &
Hutterer, 1986), Northern Highlands, are based on
misidentifications of Praomys taitae (see above
Remarks under that account and in Carleton &
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
458
M. D. CARLETON and W. T. STANLEY
Stanley, 2005). The occurrence of Acomys ignitus in
the Usambara Mts, considered a near endemic by
Burgess et al. (1998), was later traced to vouchers
collected in lowland dry habitats uncharacteristic of
EAM montane forest and delisted as an inhabitant of
the Usambaras (Stanley & Goodman, 2011). We
suspect that many such corrections, the basis of misleading distributional reports in the earlier literature,
await inspection of the original vouchers reposing
unstudied in museum cases.
Stuart et al. (1993) discussed the occasional ambiguity in distinguishing whether a record of a particular
avian species at an appropriate elevation indicates
reliance on montane forest or whether it was simply
collected in other habitat within a highland zone. We
encountered similar issues of evidentiary standards in
several contexts while compiling our list of terrestrial
small mammals that occur in Tanzanian montane
forest (Table 7; distributional references in Appendix 4). For example, species that are typically captured
in forest may also persist in degraded forest patches or
in various anthropogenic settings (Grammomys
ibeanus, Praomys taitae). Some species that are well
documented in montane forest also extend into
lowland rainforest or coastal forest (Crocidura olivieri,
Beamys hindei, Grammomys macmillani). Literature
sources about ecology are sometimes contradictory:
e.g. Crocidura hirta has been reported in montane
forest at several EAM sites (Stanley et al., 1998b,
2007b) but elsewhere is portrayed as ‘found almost
exclusively in non-forest habitats’ (Stanley &
Goodman, 2011); Crocidura jacksoni is another species
‘found almost exclusively in non-forest habitats’ in the
Usambara Mts (Stanley & Goodman, 2011), but it was
recovered from ‘montane rain forests’ on peaks in the
Taita Hills (Oguge et al., 2004); Dendromus insignis is
recorded from the ‘heath and alpine zone’ on Mt
Kilimanjaro (Grimshaw, Cordeiro & Foley, 1995) but
from several ‘forest’ sites on nearby Mt Meru (Demeter
& Hutterer, 1986). Discrepancies of this kind may
reflect ecological lability of a particular species or
taxonomic distinctions unrecognized in current classification. Gleaning habitat information from the older
literature (namely, Hollister, 1919; Swynnerton &
Hayman, 1951) can be even more equivocal; in these
cases, we recorded a taxon as montane if collected at
the same localities of montane-forest taxa familiar to
us (Sylvisorex, Hylomyscus, Praomys). Several species
occur in transitional or ecotonal habitats associated
with montane forest, whether within it or at its
margins – subalpine elfin forest and alpine heathlands
(Myosorex,
Tachyoryctes,
Dendromus
insignis,
Otomys); bamboo stands (Crocidura allex); herbaceous
or grassy thickets at forest edges and around tree falls
(Dendromus); swampy areas and sedge bogs (Dasymys
sua); marshes along rivers and streams (Pelomys
fallax). Such marginal habitats, and the species that
dwell within them, may indirectly prosper from the
cool, moist microclimates nurtured by closed-canopied,
broadleaf forest: a forest-edge specialist presupposes a
forest. Other species collected at middle elevations,
whether in montane forest proper or secondary
habitat, appear to represent a marginal occurrence at
the upper limit of their core distribution in drier
savanna grasslands or woodlands (Petrodromus tetradactylus, Sylvisorex megalura, Graphiurus kelleni,
Aethomys hindei, Zelotomys hildegardeae).
The uncertainty encapsulated by the foregoing
examples underlines two points. (1) Detailed ecological
information is unavailable for most small mammals
that inhabit the EAM, hardly a profound admission
given our still incomplete taxonomic understanding at
the species level. A collector’s considered placement of
a trap or pitfall represents a reasonable initial hypothesis of species ecology for a secretive, nocturnal small
mammal, but it is a minimal statement compared with
long-term, synecological site investigations designed to
elucidate ecophysiological requirements and trophic
niche, locomotory abilities and territoriality, mating
systems and dispersal habits. Filling these gaps in
ecological knowledge of EAM species is a challenge in
view of the considerably diminished and degraded
natural plant communities on these mountains
(Burgess et al., 2007, estimated that less than 30% of
original forest cover remains). (2) Old epithets are
available for many of the uncharacteristic highland
occurrences of shrews and rodents within the EAM.
Revalidation of their status as junior synonyms naturally invites study. One is reminded that the montaneforest endemics now identified within the Praomys
jacksoni and P. tullbergi species groups were once
treated as merely upland populations of P. jacksoni or
P. tullbergi, ‘species’ otherwise widespread in lowland
rainforest.
Establishing evidence of absence is an elusive thesis
in biogeographical study. Species vary annually in
population size and in abundance from year to year;
museum collections are biased in the time of year when
surveys are conducted; collecting methods evolve and
are variously effective for sampling different components of the local fauna; experience and/or taxic interest of collectors differ; and so on. Two lines of evidence,
per the following examples, are persuasive in deducing
absence based on the kinds of distributional data
synthesized here. Successive expeditions to the Taita
Hills – Edmund Heller in 1911, Arthur Loveridge in
1934, and Duane Schlitter in 1981 (experienced
African collectors all) – secured specimens of Praomys
taitae but none of Hylomyscus arcimontensis. Or, the
application of uniform collecting methods and trapping
hardware by Stanley and colleagues (see Stanley et al.,
1998b, 2011b) has recovered samples of Praomys taitae
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
in the Northern Highlands but not those of Hylomyscus arcimontensis. Such argumentation – multiple
visits to the same area by different collectors or
employment of comparable collecting procedures by
the same collector – encourages the conclusion that
Hylomyscus does not occur in the Northern Highlands
or Taita Hills, an important biogeographical datum
that duly affects estimates of faunal similarity. With
regard to uniformity of collecting methods, adoption of
pitfall trapping lines has certainly enhanced reliability
of soricomorph documentation in Tanzania’s mountains, e.g. compared with the incomplete picture of
shrew distributions that can be pieced together from
Swynnerton & Hayman (1951) (complemented, of
course, by the improved taxonomies impelled by study
of the larger museum series generated through pitfall
arrays). Other small mammals, such as the arboreal
sciurids and anomalurids or the fossorial chrysochlorids and spalacids, will require different sets of collecting tools and survey strategies to convincingly
document specific distributions and to illuminate
whether apparent geographical voids are real or an
artefact of collecting effort.
Notwithstanding the wealth of caveats, we believe
that the extant distributional data (Appendix 4) are
sufficient to address the central biogeographical issue
we posed: the Makambako Gap has not figured prominently in accounting for the diversity or distributional
limits of small mammals that inhabit Tanzania’s
montane forests. The possible role of the Gap as a
vicariant barrier emerges as tertiary in importance
compared with the Ruaha River and with those historical circumstances that have shaped the diversity
of terrestrial small mammals indigenous to the
Northern Highlands or Taita Hills. Descriptive biogeography, as represented by tallies of occurrence and
measures of faunal similarity, is a useful exploratory
approach to highlight possible areas of endemism and
implicate zones of vicariance (e.g. Harold & Mooi,
1994), but it does not critically invoke historical geographical events and their relevance to the genesis of
kinship patterns and to the age of origination of
endemic species. With some exceptions (Stanley &
Olson, 2005; Stanley & Esselstyn, 2010), we presently
lack a firm phylogenetic framework that speaks to the
historical patterns of diversification for most of Tanzania’s montane small mammals. Such a research
agenda will undoubtedly unfold in the next phase of
systematic study, concurrent with basic revision of
still problematic taxa recorded from the mountains
of Tanzania.
ACKNOWLEDGEMENTS
For specimen loans and/or access to collections, we
thank Robert S. Voss and Eileen Westwig (AMNH);
459
Paula D. Jenkins and Richard Sabin (BMNH);
Suzanne McLaren (CM); John D. Phelps III (FMNH);
and Judy Chupasko and Mark Omura (MCZ).
Rebecca Banasiak (FMNH) rendered the map and
photographs of study skins (Figs 1, 8), and Dave
Schmidt (USNM) photographed specimens (Figs 6, 7);
we appreciate their careful attention to detail in
helping to communicate our scientific results. Two
anonymous reviewers devoted careful scrutiny to the
manuscript and improved the clarity of our communication. Permits issued to W.T.S. to conduct research
in Tanzania were granted by the Tanzania Commission for Science and Technology, the Tanzania Wildlife
Research Institute, and the Ministry of Natural
Resources and Tourism. Support for fieldwork by
W.T.S. was provided by the National Geographic
Society (Grants 5053–93, 5244–94, 5711–96), the
Critical Ecosystem Partnership Fund, and the Field
Museum of Natural History (Field Museum/IDP
Foundation, Inc. African Training Fund, as well as
the Barbara Brown, Council on Africa, Ellen Thorne
Smith, and Marshall Field Funds). At various times,
Steven M. Goodman, Kim M. Howell, Philip M.
Kihaule, Sophy J. Machaga, and Maiko M. Munissi
helped W.T.S. to collect specimens, and Tim Davenport supplied logistical support within Tanzania.
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Royal des Sciences Naturelles de Belgique, Biologie 73:
27–71.
Verheyen WN, Hulselmans JLJ, Dierckx T, Mulungu L,
Leirs H, Corti M, Verheyen E. 2007. The characterization
of the Kilimanjaro Lophuromys aquilus True 1892 population and the description of five new Lophuromys species
(Rodentia, Muridae). Bulletin de l’Institut Royal des Sciences Naturelles de Belgique, Biologie 77: 23–75.
Voss RS, Marcus LF. 1992. Morphological evolution in
muroid rodents. II. Craniometric factor divergence in seven
Neotropical genera, with experimental results from Zygodontomys. Evolution 46: 1918–1934.
Voss RS, Marcus LF, Escalante P. 1990. Morphological
evolution in muroid rodents I. Conservative patterns of
craniometric covariance and their ontogenetic basis in the
Neotropical genus Zygodontomys. Evolution 44: 1568–
1587.
Wasser SK, Lovett JC. 1993. Introduction to the biogeography and ecology of the rain forests of eastern Africa. In:
Lovett JC, Wasser SK, eds. Biogeography and ecology of the
rain forests of eastern Africa. Cambridge: Cambridge University Press, 3–7.
White F. 1978. The Afromontane region. In: Werger MJA, ed.
Biogeography and ecology of Southern Africa. The Hague:
Junk, 463–513.
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© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
464
M. D. CARLETON and W. T. STANLEY
APPENDIX 1
GAZETTEER OF COLLECTING LOCALITIES
Below are the 59 collecting localities used in preparing
distributional maps and defining analytical samples
(also see Fig. 14), along with the collector, year of
collection, and institutional repository. The bold-faced
portion of an abbreviated locality corresponds to the
latitude and longitude provided; original locality data
as found on specimen tags and catalogue numbers of
specimens examined are supplied within species
accounts. Sources of geographical coordinates include
those given by the collector (C), whether determined
from topographic maps or global positioning devices;
the National Geospatial-Intelligence Agency (NGA),
which provides on-line access to the U.S. Board on
Geographic Names database; faunal publications
(Swynnerton & Hayman, 1951; Loveridge, 1953; Davis
& Misonne, 1964; Aggundey & Schlitter, 1986; Ansell
& Dowsett, 1988); and in one instance, estimation
using Google Earth (GE).
KENYA
1. Chyulu Hills, 1829 m; 2°35′S, 37°50′E (NGA, as
Chyulu Range); H. J. Turner (USNM), Jun 1938
– Praomys taitae.
2. Mount Mbololo, Taita Hills, 1524 m; 3°17′S,
38°28′E (NGA, as Mbololo Hill); E. Heller
(USNM), Nov 1911, and A. Loveridge (MCZ), Apr
1934; type locality of Epimys taitae Heller, 1912 –
Praomys taitae.
3. Mount Umengo, Taita Hills; 3°18′S, 38°19′E
(Davis & Misonne, 1964; Aggundey & Schlitter,
1986); E. Heller (USNM), Nov 1911 – Praomys
taitae.
4. Ngangao Forest, Taita Hills, 1700 m; 3°22′S,
38°21′E (C); D. A. Schlitter (CM), Sep 1987 –
Praomys taitae.
TANZANIA
5. 10.5 km N and 3.5 km W Maua, Kilimanjaro
National Park, Mount Kilimanjaro, 2897 m;
3°10.627′S, 37°26.413′E (C, GPS); W. T. Stanley
(FMNH), Jul–Aug 2002 – Praomys taitae.
6. 7 km N and 2.5 km W Maua, Kilimanjaro
National Park, Mount Kilimanjaro, 2470 m;
3°12.459′S, 37°26.818′E (C, GPS); W. T. Stanley
(FMNH), Jul 2002 – Praomys taitae.
7. 4 km N and 1.5 km W Maua, Mount Kilimanjaro, 2043 m; 3°14.404′S, 37°27.502′E (C, GPS);
W. T. Stanley (FMNH), Aug 2002 – Praomys
taitae.
8. Minja Forest Reserve, North Pare Mountains,
1572 m; 3.58149°S, 37.67730°E (C, GPS); W. T.
Stanley (FMNH), Jul 2006 – Praomys taitae.
9. Kindoroko Forest Reserve, North Pare Mountains, 1688 m; 3.76039°S, 37.64726°E (C, GPS);
W. T. Stanley (FMNH), Jul 2006 – Praomys
taitae.
10. Mt Meru, Arusha National Park, 2300 m;
3.24725°S, 36.80066°E (C, GPS); W. T Stanley
(FMNH), Jul 2009 – Praomys taitae.
11. North Rim Ngorongoro Crater, 2286 m; c.
3°05′S, 35°34′E (GE); A. C. Brooks (BMNH), Feb–
Mar 1954 – Praomys taitae.
12. Old Mbulu Reserve (= Kainam, fide Swynnerton & Hayman, 1951), 1830 m; 3°55′S, 35°35′E
(NGA; Davis & Misonne, 1964); A. L. Moses
(AMNH), Nov 1928; type locality of Praomys jacksoni octomastis Hatt, 1940 – Praomys taitae.
13. 3 km E and 0.7 km N Mhero, Chome Forest
Reserve, South Pare Mountains, 2000 m; 4°17′S,
37°55′40″E (C, map); W. T. Stanley (FMNH), Aug
1994 – Praomys taitae.
14. 7 km (by air) S Bombo, Chome Forest Reserve,
South Pare Mountains, 1100 m; 4°20′S, 38°00′E
(C, map); S. M. Goodman & W. T. Stanley
(FMNH) Jul 1993 – Praomys taitae.
15. Sunga, West Usambara Mountains, 2134 m;
4°32′S, 38°14′E (NGA; Davis & Misonne, 1964);
C. A. Hubbard (USNM), Nov 1962 – Praomys
taitae.
16. 4.4 km W Mt Mhinduro, Kwamgumi Forest
Reserve, 230 m; 4°56′30″S, 38°44′E (C, map); W.
T. Stanley (FMNH), Jul 1994 – Praomys taitae.
17. Magrotto, 915 m (fide Swynnerton & Hayman,
1951); 05°07′S, 38°45′E (NGA, as Magrotto
Estate); A. Loveridge (MCZ), Jul 1939 – Praomys
taitae.
18. 8 km WNW Amani, East Usambara Mountains,
1000 m; 5°2′S, 38°37′E (C, map); S. M. Goodman
& W. T. Stanley (FMNH), Aug 1992 – Praomys
taitae.
19. 6 km NW Amani, East Usambara Mountains,
1100 m; 5°4′S, 38°36′E (C, map); S. M. Goodman
& W. T. Stanley (FMNH), Jul 1992 – Praomys
taitae.
20. 4.5 km ESE Amani, East Usambara Mountains,
870 m; 5°6′S, 38°36′E (C, map); S. M. Goodman &
W. T. Stanley (FMNH), Aug 1992 – Praomys
taitae.
21. 4.5 km WNW Amani, East Usambara Mountains, 870 and 900 m; 5°6′S, 38°36′E (C, map); S.
M. Goodman & W. T. Stanley (FMNH), Aug 1992;
W. T. Stanley, Aug 1993 – Praomys taitae.
22. 11 km NW Korogwe, West Usambara Mountains, 1120 m; 5°4′S, 38°26′E (C, map); S. M.
Goodman (FMNH), Jul 1991 – Praomys
taitae.
23. 12.5 km NW Korogwe, West Usambara Mountains, 1300 m; 5°4′S, 38°25′E (C, map); S. M.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
465
L. Victoria
KENYA
1
11
5
6
7
10
12
2
3
8
9
4
13 14
15
18
19 16
22
17
23 20 21
24
25
TANZANIA
28
29
35
L
e Ta
ak
36
n ga
38
ik a
ny
43
48 4746
49
51
44
50 45
27 26
37
30
32 31
33
34
40
39
41
42
52
lawi
Lake M a
ZAMBIA
MALAWI
MOZAMBIQUE
53
54
56 58
55
59
57
Figure 14. Fifty-nine major collecting localities of Praomys reported herein, sequentially numbered from north to south.
Numbers refer to the localities gazetted in Appendix 1 and to those used to define the 21 OTUs (see Material and
Methods).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
466
24.
25.
26.
27.
28.
29.
30.
31.
32.
33.
34.
35.
36.
37.
M. D. CARLETON and W. T. STANLEY
Goodman (FMNH), Jul 1991; S. M. Goodman &
W. T. Stanley (FMNH), Aug 1992; W. T. Stanley
(FMNH), Aug 1993 – Praomys taitae.
3.6 km E and 4.7 km S Gombero, Nguru North
Forest Reserve, Nguu Mountains, 1430 m;
5°28′10″S, 37°28′55″E (C, map); W. T. Stanley
(FMNH), Aug 2000 – Praomys taitae.
5.6 km S and 3 km E Gombero, Nguru North
Forest Reserve, Nguu Mountains, 1180 m;
5°28′40″S, 37°28′30″E (C, map); W. T. Stanley
(FMNH), Jul–Aug 2000 – Praomys taitae.
8 km N and 3 km W Mhonda, Manyangu
Forest Reserve, Nguru Mountains, 1000 m;
6°02′50″S, 37°32′50″E (C, map); W. T. Stanley
(FMNH), Jul 1997 – Praomys taitae.
6 km N and 6 km W Mhonda, Nguru South
Forest Reserve, Nguru Mountains, 1500 m;
6°03′50″S, 37°31′25″E (C, map); W. T. Stanley
(FMNH), Aug 1997 – Praomys taitae.
1 km E and 0.75 km S Mt Munyera, MamiwaKisara Forest, Ukaguru Mountains, 1900 m;
6°22′45″S, 36°56′10″E (C, map); W. T. Stanley
(FMNH), Jul–Aug 1999 – Praomys taitae.
1 km E and 1.5 km S Mt Munyera, MamiwaKisara Forest, Ukaguru Mountains, 1840 m;
6°23′20″S, 36°57′00″E (C, map); W. T. Stanley
(FMNH), Aug 1999 – Praomys taitae.
Vituri, Uluguru Mountains; 06°51′S, 37°44′E
(Swynnerton & Hayman, 1951); A. Loveridge
(MCZ), Oct 1926 – Praomys taitae.
Bagilo, Uluguru Mountains, 1675–1980 m (fide
Swynnerton & Hayman, 1951); 06°54′S, 37°44′E
(NGA, as Bagiro); A. Loveridge (MCZ), Sep 1926
– Praomys taitae.
5.1 km W and 2.3 km N Tegetero, Uluguru
North Forest, Uluguru Mountains, 1535 m;
6°55′12″S, 37°41′00″E (C, map); W. T. Stanley
(FMNH), Aug 1996 – Praomys taitae.
3 km W and 1.3 km N Tegetero, Uluguru North
Forest, Uluguru Mountains, 1345 m; 6°55′45″S,
37°42′20″E (C, map); W. T. Stanley (FMNH), Jul
1996 – Praomys taitae.
Mikumi National Park, Malundwe Mountains,
985 m; 7°23.719′S, 37°18.279′E (C, GPS); W. T.
Stanley (FMNH), Jul 2005 – Praomys taitae.
near Chugu Peak, Mwofwomero Forest, Rubeho
Mountains, 1900 m; 6.83370°S, 36.57198°E (C,
GPS); W. T. Stanley (FMNH), Jul 2007 – Praomys
taitae.
Mwofwomero Forest Reserve, Rubeho Mountains, 1923 m; 6.91585°S, 36.55954°E (Collector
GPS); W. T. Stanley (FMNH), Jul 2007 – Praomys
taitae.
Ilole Forest, Rubeho Mountains, 1878 m;
7.43774°S, 36.72729°E (C, GPS); W. T. Stanley
(FMNH), Aug 2007 – Praomys taitae.
38. 9 km E Udekwa, Ndundulu Forest, Udzungwa
Mountains, 1900 m; 7°45.117′S, 36°27.803′E (C,
GPS); W. T. Stanley (FMNH), Jul 2003 – Praomys
taitae.
39. 19.5 km N and 0.5 km W Chita, Udzungwa
Scarp Forest Reserve, Udzungwa Mountains,
2000 m; 8°20′50″S, 35°56′20″E (C, map); W. T.
Stanley (FMNH), Sep 1995 – Praomys taitae.
40. 4 km W and 5 km N Chita, Udzungwa Scarp
Forest Reserve, Udzungwa Mountains, 1460 m;
8°28′30″S, 35°54′25″E (C, map); W. T. Stanley
(FMNH), Aug 1995 – Praomys taitae.
41. 3.5 km W and 1.7 km N Chita, Udzungwa
Scarp Forest Reserve, Udzungwa Mountains,
910 m; 8°30′20″S, 35°54′30″E (C, map); W. T.
Stanley (FMNH), Aug 1995 – Praomys taitae.
42. 4.5 km W Chita, Udzungwa Scarp Forest
Reserve,
Udzungwa
Mountains,
600 m;
8°31′10″S, 35°54′15″E (C, map); W. T. Stanley
(FMNH), Aug 1995 – Praomys taitae.
43. Kigogo, Udzungwa Mountains, 1830 m (fide
Swynnerton & Hayman, 1951); 8°37′S, 35°15′E
(Swynnerton & Hayman, 1951); A. Loveridge
(MCZ), Jan 1930 – Praomys taitae.
44. Madehani, Livingstone Mountains, 2135 m (fide
Swynnerton & Hayman, 1951); 9°20′S, 34°01′E
(Swynnerton & Hayman, 1951); A. Loveridge
(MCZ), Feb 1930 – Praomys melanotus.
45. Madehani Forest, Livingstone Mountains,
2100 m; 09.33512°S, 33.98446°E (C, GPS);
W. T. Stanley (FMNH), Jul 2008 – Praomys
melanotus.
46. Nyamwanga, Poroto Mountains, 1950 m (fide
Swynnerton & Hayman, 1951); 9°04′S, 33°40′E
(Swynnerton & Hayman, 1951); A. Loveridge
(MCZ), Mar 1930; type locality of Praomys tullbergi melanotus G. M. Allen & Loveridge, 1933 –
Praomys melanotus.
47. Ngozi Crater, Poroto Mountains, 2250 m;
08.99996°S, 33.56190°E (C, GPS); W.T. Stanley
(FMNH), Aug 2008 – Praomys melanotus.
48. Igale, Poroto Mountains, 1830 m (fide Swynnerton & Hayman, 1951); 9°02′S, 33°24′E (NGA, as
Igali); A. Loveridge (MCZ), Apr 1930 – Praomys
melanotus.
49. 7 km E and 2.5 km N Ilolo, Rungwe Forest
Reserve, Mt Rungwe, 2410 m; 9°11′30″S,
33°39′25″E (C, map); W. T. Stanley (FMNH), Sep
1998 – Praomys melanotus.
50. 5 km E Ilolo, Rungwe Forest Reserve, Mt
Rungwe, 1870 m; 9°10′05″S, 33°38′15″E (C, map);
W. T. Stanley (FMNH), Aug 1998 – Praomys
melanotus.
51. Ilolo, Mt Rungwe, 1400 m (fide Swynnerton &
Hayman, 1951); 09°10′S, 33°35′E (NGA); A. Loveridge (MCZ), Mar 1930 – Praomys melanotus.
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
SYSTEMATICS OF PRAOMYS
MALAWI
52. Matipa-Wilindi Ridge, Misuku Mountains,
1830 m; 9°39′S, 33°26′E (NGA, as Matipa Hill); A.
Loveridge (MCZ), Oct 1948 – Praomys melanotus.
53. Zomba, 800–900 m (fide Ansell & Dowsett,
1988); 15°23′S, 35°20′E (NGA; Ansell & Dowsett,
1988); H. E. Anthony & G. C. Shortridge (AMNH,
Vernay Nyasaland Expedition), Jun 1946 –
Praomys delectorum.
54. Cholo Mountain (= Thyolo Mt), 1462 m (fide
Ansell & Dowsett, 1988); 16°05′S, 35°03′E (NGA;
Ansell & Dowsett, 1988); H. E. Anthony & G. C.
Shortridge (AMNH, Vernay Nyasaland Expedition), Sep 1946 – Praomys delectorum.
55. Lichenya Plateau, 1830 m; 15°59′S, 35°32′E
(NGA); A. Loveridge (MCZ), Aug 1948 – Praomys
delectorum.
56. Lichenya Hut, Mount Mulanje, 1840 m;
15°58.458′S, 35°33.028′E (C, GPS); W. T. Stanley
(FMNH), Aug 2004 – Praomys delectorum.
57. Mulanje Plateau; 15°58′S, 35°38′E (NGA); S. A.
Neave (BMNH), May 1910, and H. E. Anthony &
G. C. Shortridge (AMNH, Vernay Nyasaland
Expedition), Jun–Jul 1946; type locality of
Epimys delectorum Thomas, 1910 – Praomys
delectorum.
58. Edge of Lujeri Tea Estate and Mulanje
Forest Reserve, Mount Mulanje, 1000 m;
15°57.692′S, 35°39.247′E (C, GPS); W. T. Stanley
(FMNH), Aug 2004 – Praomys delectorum.
59. Chisongeli Forest, Mount Mulanje, 1575 m;
15°59.996′S, 35°43.412′E (C, GPS); W. T. Stanley
(FMNH), Aug 2004 – Praomys delectorum.
APPENDIX 2
The following specimens with post-cranial skeletons
were examined to verify occurrence of the entepicondylar foramen in species of the Praomys delectorum group.
Praomys delectorum (N = 19): Malawi, Mt Mulanje,
Mulanje Forest Reserve (FMNH 181228, 181230–
181232); Chisongeli Forest (FMNH 181234, 181237–
181239, 181241, 181243–181245, 181248–181253,
181255).
467
Praomys melanotus (N = 20): Tanzania, Mt
Rungwe, Rungwe Forest Reserve (FMNH 163734–
163738, 163740–163743, 163745–163749, 163751–
163756).
Praomys taitae (N = 27): Tanzania, South Pare Mts,
Chome Forest Reserve (FMNH 151311, 151313–
151315, 151317–151319, 151321–151323, 151325–
151327, 151329); Tanzania, Udzungwa Mts (FMNH
155624–155636).
APPENDIX 3
Listed below are adult specimens of Hylomyscus arcimontensis used to extract canonical variates from
discriminate function analysis of Tanzanian montane
samples (see Fig. 12). Localities are listed only to
mountain name; full locality data are documented in
Carleton & Stanley (2005).
Tanzania: South Pare Mountains, 1100 and 2000 m
(FMNH 151253, 153946, 153947, 153949–153951);
West Usambara Mountains, 1250 and 1300 m (FMNH
147252–147254, 147256, 147258, 147260–147262,
147264–147266, 147268–147270, 147272–147274,
147276–147280, 147282–147284, 147286–147288,
150127–150129, 150131, 150132, 150135–150137,
150154–150156, 150160–150162, 150164, 150166,
150168–150170, 150439, 150442, 150446, 150451,
151244–151246); East Usambara Mountains, 900 and
1100 m (FMNH 147290, 147291, 150118, 150119,
150121–150124, 150139, 150140, 150142, 150144–
150146, 150148–150150, 150153, 150433, 151248,
151250–151252); Nguru and Nguu Mountains, 1100,
1180, 1430, and 1500 m (FMNH 161270–161272,
168175, 168176); Ukaguru Mountains, 1840 and
1900 m (FMNH 166916–166925); Uluguru Mountains,
1345 and 1535 m (FMNH 158343–158353, 158355,
158495, 158500, 158505, 158573; MCZ 22505, 22507,
22508); Udzungwa Mountains, 910, 1460, and 2000 m
(FMNH 155390, 155392, 155555–155558, 155562–
155572; MCZ 26499); Livingstone Mountains (MCZ
26406, 26410, 26412, 26414); Mount Rungwe, 1870,
2140, and 2410 m (AMNH 81372, 81374; FMNH
163584–163588, 163590–163600).
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
Afrosoricida: Chrysochloridae
Chrysochloris stuhlmanni
Macroscelidea: Macroscelididae
Petrodromus tetradactylus
Rhynchocyon petersi
R. uzungwensis
Soricomorpha: Soricidae
Congosorex phillipsorum
Crocidura allex
C. desperata
C. elgonius
C. fuscomurina
C. hildegardeae
C. hirta
C. jacksoni
C. luna
C. monax
C. montis
C. olivieri
C. tansaniana
C. telfordi
C. usambarae
C. xantippe
Myosorex geata
M. kihaulei
M. zinki
Sylvisorex aequatorius‡
S. granti
S. howelli
S. megalura‡
Rodentia: Sciuridae
Heliosciurus mutabilis
H. undulatus
Paraxerus vexillarius
Rodentia: Gliridae
Graphiurus kelleni
G. murinus
Rodentia: Spalacidae
Tachyoryctes daemon
Rodentia: Nesomyidae
Beamys hindei
Cricetomys ansorgei
Dendromus insignis
D. mystacalis
D. nyasae
D. nyikae
X
Xe
X
X
X
X
Xe
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
NPA
NHI
Species
TAI
Tanzanian mountains*
Order: family
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
WUS
X
X
X
X
SPA
X
X
X
X
X
X
X
X
X
X
X
X
Xe
X
X
X
X
X
X
EUS
X
X
X
X
X
NGU
X
X
X
X
X
X
X
X
NGR
X
X
X
X
X
X
UKA
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Xe
Xe
X
UDZ
X
X
X
X
X
MAL
X
X
RUB
X
X
X
ULU
X
X
X
X
X
X
X
X
X
SHI
20, 21, 25, 26
9, 34
5, 14
20, 31, 32
14, 26, 27, 34
26
5
9, 20
3, 9, 20, 30, 34
6, 34
5, 6, 9, 34
5, 20, 34
29
3, 5
10, 11
5, 21, 26, 27, 33
10, 15, 26, 33
3, 8, 24, 30, 33
24, 26, 27, 31, 33
15, 33
5, 27
5, 26, 33, 34
3, 10
4, 5, 15, 23, 25, 28
10, 33
26
24, 26, 33
10, 26, 33
12, 18
18, 21
5, 18, 21
7, 15
5
21, 23, 24, 28, 33
15, 26, 27, 33
8, 33, 34
24, 30, 33, 34
17
10, 34
Authority†
Occurrence of small mammal species in Tanzania’s Northern and Southern Highlands and in individual units of the EAM chain. Presence (X) based
on vouchered museum specimens and presumed endemic species (Xe) are indicated.
APPENDIX 4
468
M. D. CARLETON and W. T. STANLEY
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
23
6
X
X
Xe
Xe
Xe
X
X
Xe
X
X
18
0
X
X
X
X
X
X
X
7
0
X
X
X
14
0
X
X
X
X
X
X
X
25
0
X
X
X
X
X
X
X
X
X
X
30
1
X
X
X
X
X
X
X
X
6
0
X
X
12
0
X
X
X
8
0
X
X
X
X
22
1
X
X
X
X
X
X
Xe
X
X
4
0
X
7
0
X
X
X
31
2
X
X
X
X
X
X
X
X
X
X
X
X
19
0
X
X
X
X
X
X
X
X
X
X
34
20, 30
34, 37
9, 20
34, 39
34, 39
5, 9, 27, 34
12, 20, 26, 27
9, 19, 20, 27, 34
2, 20, 30
40
21, 40
40
40
38
5, 9, 20, 25
5, 26, 34
34, 35
1, 35, 36
1, 13, 36
36
9, 34
This study
This study
3, 5, 16, 34
9
*Mountain abbreviations: EUS, East Usambara Mts; MAL, Malundwe Mts; NGU, Nguu Mts; NGR, Nguru Mts; NHI, Northern Highlands (Mt Kilimanjaro, Mt Meru, Ngorongoro Crater Highlands);
NPA, North Pare Mts; RUB, Rubeho Mts; SHI, Southern Highlands (Livingstone Mts, Poroto Mts, Mt Rungwe); SPA, South Pare Mts; TAI, Taita Hills; UDZ, Udzungwa Mts; UKA, Ukaguru Mts;
ULU, Uluguru Mts; WUS, East Usambara Mts.
†Authorities: (1) Carleton & Schaefer Byrne (2006); (2) Carleton & Stanley (2005); (3) Demeter & Hutterer (1986); (4) Goodman et al. (1995); (5) Grimshaw et al. (1995); (6) Grubb (1982); (7) Heller
(1912); (8) Hollister (1918); (9) Hollister (1919); (10) Hutterer (2005); (11) Hutterer, Jenkins & Verheyen (1991); (12) Kerbis Peterhans et al. (2008); (13) Lawrence & Loveridge (1953); (14) Musser
& Carleton (2005); (15) Oguge et al. (2004); (16) Rambau, Robinson & Stanyon (2003); (17) Rovero et al. 2008; (18) Stanley & Esselstyn (2010); (19) Stanley & Foley (2008); (20) Stanley & Goodman
(2011); (21) Stanley & Hutterer (2000); (22) Stanley & Hutterer (2007); (23) Stanley & Olson (2005); (24) Stanley et al. (1996); (25) Stanley et al. (1998a); (26) Stanley et al. (1998b); (27) Stanley
et al. (2005a); (28) Stanley et al. (2005b); (29) Stanley et al. (2005c); (30) Stanley et al. (2007a); (31) Stanley et al. (2007b); (32) Stanley et al. (2007c); (33) Stanley, Goodman & Hutterer (2011a);
(34) Swynnerton & Hayman (1951); (35) Taylor et al. (2009); (36) Taylor et al. (2011); (37) Verheyen (1968); (38) Verheyen et al. (2002); (39) Verheyen et al. (2003); (40) Verheyen et al. (2007).
‡Assigned to Sylvisorex rather than Suncus following the recommendation of Dubey et al. (2008).
Rodentia: Muridae
Aethomys hindei
Dasymys incomptus
D. sua
Grammomys dolichurus
G. ibeanus
G. macmillani
Hylomyscus arcimontensis
Lophuromys aquilus
L. kilonzoi
L. machangui
L. makundii
L. verhageni
Mus musculoides
M. triton
Otomys lacustris
O. sungae
O. uzungwensis
O. zinki
Pelomys fallax
Praomys melanotus
P. taitae
Rhabdomys dilectus
Zelotomys hildegardeae
Rodentia: Anomaluridae
Anomalurus derbianus
Rodentia: Bathyergidae
Cryptomys hottentotus
Heliophobius argenteocinereus
Number of Species
Number of Endemics
SYSTEMATICS OF PRAOMYS
© 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 165, 420–469
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