Zootaxa 2985: 41–54 (2011)
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Copyright © 2011 · Magnolia Press
ISSN 1175-5326 (print edition)
Article
ZOOTAXA
ISSN 1175-5334 (online edition)
Morphometric and morphological variation in Myotis simus Thomas
(Chiroptera, Vespertilionidae), with an appraisal of the identity of
Myotis guaycuru Proença based on the analysis of the type material
RICARDO MORATELLI1, ADRIANO L. PERACCHI2 & JOÃO A. DE OLIVEIRA3
1
Campus Fiocruz da Mata Atlântica, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil. E-mail: [email protected]
Instituto de Biologia, Universidade Federal Rural do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. E-mail: [email protected]
3
Departamento de Vertebrados, Museu Nacional, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
E-mail: [email protected]
2
Abstract
Twelve species are recognized in the South American bat genus Myotis Kaup (Vespertilionidae, Myotinae), with several
nominal forms currently regarded as synonyms, among them Myotis guaycuru Proença, 1943. Its holotype, so far the only
specimen assigned to the species, has not been examined in recent taxonomic reviews. To address the taxonomic status of
M. guaycuru, we located and redescribed its holotype and compared it to representatives and/or descriptions of all South
American species in the genus. Qualitative traits, namely the plagiopatagium attached at ankles, the short and wooly fur
and the lingually displaced P3, unambiguously assign the holotype of M. guaycuru to Myotis simus Thomas (1901). The
analysis of cranial variation and pelage color across a wide geographical range of M. simus reveals morphometric and morphological discontinuity between Bolivian and Amazonian/Peruvian samples, the latter including topotypes of M. simus.
The holotype of M. guaycuru was found to be morphometrically and morphologically more similar to these Amazonian
samples than to the geographically nearer Bolivian sample, preventing the use of this nominal form to refer to the Bolivian
population if its distinction suggested by morphometric analyses is confirmed by the analyses of other character systems.
Key words: Myotis, Myotinae, taxonomy, synonymy, multivariate analyses, South America
Introduction
Based primarily on LaVal’s (1973) revisionary work on Neotropical Myotis Kaup, 1829 (Vespertilionidae, Myotinae), Wilson (2008) has recently recognized 12 valid names to South American species. Several other proposed
names have been regarded as synonyms, among them, Myotis guaycuru, described by Proença (1943) on the basis
of one specimen collected in 1940 in Salobra, Paraguay Basin, Mato Grosso do Sul, Brazil (Travassos 1940). The
taxonomic status of M. guaycuru was f irst questioned by La Val (1973), who t entatively regarded this taxon as a
probably senior synonym of Myotis riparius Handley, 1960. Subsequently, López-González et al. (2001) considered Myotis guaycuru a junior synonym of Myotis simus Thomas, 1901, an assignment followed by Wilson (2008).
However, neither LaVal (1973) nor López-González et al. (2001) examined the holotype.
Myotis simus was described by Thomas (1901) based on one female specimen from Loreto, Peru. According to
Thomas (1901) description, no recognized species resembles M. simus in external traits, the main diagnostic characters being the wings attached at the toes or at ankles by a narrow band of membrane and the very short fur (Baud
and Menu 1993; López-González et al. 2001; López-González 2005). Myotis riparius was descr ibed by Han dley
(1960) for a ser ies from Darien, Panama. It was originally proposed as a subspec ies of M. simus, but was subsequently raised t o the sp ecies level b y L aVal ( 1973). Myotis riparius can be di stinguished from M. simus by th e
attachment of its plagiopatagium to the base of the toes by a broad band of membrane, by its longer and generally
bicolored f ur, and by th e P3 not cr owded to the lingual side ( LaVal 1973; López-González et al. 2 001; LópezGonzález 2005).
Accepted by P. Cordeiro-Estrela: 28 Jun. 2011; published: 4 Aug. 2011
41
Herein, as part of an ongoing systematic and biogeographic review of South American species of Myotis, and
in order to determine the taxonomic status of M. guaycuru, we qualitatively compared its holotype with type specimens or original descriptions of other South American species. Subsequently, we analyzed the craniometric variation within and among geographic samples of M. simus and classified the cranial morphology of the type specimen
of M. guaycuru within this morphometric context, in order to evaluate the possible application of this nominal form
in the recognition of geographic units within M. simus.
Material and methods
The holotype of M. guaycuru: Among a series of specimens donated to the Instituto de Biologia (Universidade
Federal Rural do Rio de Jan eiro, UFRRJ), by the Instituto Oswaldo Cruz (Fundação Oswaldo Cruz), there was a
specimen bearing an original label which reads: “Myotis guaycuru, Salobra, M. Grosso, 237”. This specimen was
deposited in the Adriano Lúcio Peracchi Collection at Instituto de Biologia, UFRRJ, under the number ALP 9277,
and was reco gnized as t he ho lotype o f M. guaycuru after compar isons with the original descr iption and photographs given by Proença (1943).
Comparisons: the holotype of M. guaycuru (ALP 9277) was compared with the currently recognized South
American species of Myotis, represented by their type specimens, original descriptions and/or redescriptions provided by LaVal (1973). The type specimens used in comparisons were: M. albescens (É. Geoffroy, 1806) (AMNH
205195, neotype), M. levis levis (I. Geoffroy, 1824) (MNHN type no. 203, lectotype), M. keaysi keaysi J.A. Allen,
1914 (AMNH 15814, holotype), M. nesopolus larensis LaVal, 1973 (AMNH 130709, holotype), M. riparius Handley, 1960 (USNM 310255, holotype) and M. ruber (É. G eoffroy, 1806) (USNM 115097, neotype). The original
descriptions used in comparisons wer e: M. aelleni B aud, 1 979, M. atacamensis ( Lataste, 1892 ), M. chiloensis
(Waterhouse, 1840), M. levis dinellii (Thomas, 1902), M. keaysi pilosatibialis LaVal, 1973, M. nigricans nigricans
(Schinz, 1821), M. oxyotus (Peters, 1867) and M. simus Thomas, 1901.
Specimens selection: Specimens of M. simus in collections were i dentified by a set of qualitative characters
regarded as diagnostic by Thomas (1901), LaVal (1973), López-González et al. (2001), López-González (2005),
Moratelli (2008) and Wilson (2008), as follows: plagiopatagium attached at the level of the toes by a narrow band
of membrane or at the level of the ankles (q.v., López-González et al. 2001: 141, fig. 1), extremely short and woolly
fur, tips of dorsal hairs not contrasting with bases, and absence of fringe of hairs along the trailing edge of the uropatagium. To address t he vari ation i n qualitative and quant itative characters among South Ameri can population
samples, 99 specimens referable to M. simus from Bolivia, Brazil, Ecuador and Peru were analyzed, 47 of which
from Bol ivia, B razil an d P eru ha ving b een included in the mul tivariate statistical a nalyses. A list of sp ecimens
examined with their localities is in the Appendix.
Samples analyzed: Considering t hat sex ratios i n each geo graphic sampl e vari ed co nsiderably, wi th mal es
usually l ess r epresented t han females, to av oid possi ble ef fects of seco ndary sex ual di morphism r elated to t his
unbalanced design, o nly f emales wer e i ncluded i n t he geog raphic an alyses. T he f ollowing g eographic sampl es
were available for morphometric analyses (Figure 1): 1: Cercado, Beni, Bolivia (N = 20); 2: Borba, Amazon as,
Brazil (N = 5); 3: Manaus, Amazonas, Brazil (N = 5); 4: Parintins, Amazonas, Brazil (N = 9); 5: El Refugio, Santa
Cruz, Bolivia (N = 1); 6: Salobra, Mato Grosso do Sul, Brazil (type specimen of M. guaycuru, N = 1); 7: Rio Juruá,
Amazonas, Brazil (N = 1); 8: Ucayali, Loreto, Peru (topotypes of M. simus, N = 3); and 9: San Juan, Pasco, Peru
(N = 2).
Quantitative data: All observations and measurements are from adult individuals with closed epiphyses. Fifteen cranial and five external dimensions were measured using a digital caliper accurate to 0.02 mm. The measurements, reported in millimeters (mm), and their abbreviations are defined as follows (lengths were measured from
the anteriormost point of the first structure to the posteriormost point of the second structure mentioned below):
greatest length of skull (GLS), from the premaxillae, including the incisors, to the occiput; condylo-canine length
(CCL), from the occipital condyles to the upper canines; condylo-incisive length (CIL), from the occipital condyles
to the upper incisors; basal length (BL), from the foramen magnum to the upper incisors; zygomatic breadth (ZB),
greatest breadth across the outer edges of the zygomatic arches; mastoid breadth (MAB), greatest cranial breadth
across the mastoid region; braincase breadth (BCB), greatest breadth of the globular part of the braincase; interorbital breadth (IOB), least breadth across orbital bulges; postorbital breadth (P OB), l east breadth across frontals
posterior to the postorbital bulges; breadth across canines (BAC), greatest breadth across outer edges of the crowns
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MORATELLI ET AL.
of upper canines; breadth across molars (BAM), greatest breadth across outer edges of the crowns of upper molars;
maxillary toothrow length (MTL), from the upper canine crown to the crown of M3; molariform toothrow length
(M13), from the crown of M1 to the crown of M3; mandibular length (MAL), from the dentary, without incisors, to
the angular process; mandibular toothrow length (MAN), from the lower canine to m3; thumb length (THL), from
the proximal end of the metacarpal to the tip of the claw; forearm length (FA), from the elbow to the distal end of
the forearm including carpals; third metacarpal length (3MC), from the distal end of the forearm to the distal end
of the third metacarpal; and length of the dorsal (LDH) and ventral hairs (LVH), from the base to the tip of the hair,
measured between scapulae. The weight, reported in grams, was obtained from the skin tags.
FIGURE 1. Geographic mapping of samples analyzed in the present study: (1) Cercado, Beni, Bolivia; (2) Borba, Amazonas,
Brazil; (3) Manaus, Amazonas, Brazil; (4) Parintins, Amazonas, Brazil; (5) El Refugio, Santa Cruz, Bolivia; (6) Salobra, Mato
Grosso do Sul, Brazil (type specimen of M. guaycuru) (7) Rio Juruá, Amazonas, Brazil; (8) Ucayali, Loreto, Peru; and (9) San
Juan, Pasco, Peru.
Analyses of geographic variation: All available specimens were included in a Principal Components Analysis (PCA) to summarize the general trends of size and shape variation within the total dataset treated as a unique
sample. To assess patterns of craniometrical geographic variation, a C anonical Variate Analysis (CVA) was performed o n l ocality sampl es t o assess craniometric characters t hat b est discriminate amo ng g eographic sampl es
(Neff & Marcus 1980; Manly 1994). Localities represented by on e to three specimens were not included in this
analysis, but classified a posteriori to the larger samples on the basis of bootstrapped Mahalanobis distances. As
multivariate procedures require complete data matrices, missing values (2.5% of total dataset) were estimated from
the existing d ata u sing t he expectation-maximization al gorithm (Little & R ubin 1 987; Strauss et al. 2003 ). For
descriptive and comparative purposes, mean and range of each character were reported for the largest samples. The
GEOGRAPHIC VARIATION IN MYOTIS SIMUS
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statistical significance of differences among geographical samples was assessed by single classification analyses of
variance (ANOVAs). To test if the isolation-by-distance model adequately describes the pattern of geographical
variation revealed for M. simus, we assessed the correlation between the geographical and morphometric distance
matrices by means of a non-parametric Mantel’s test (Mantel 1967).
All analyses were performed in Matlab for Windows, version 4.2c (Mathworks 1994), using functions written
by R. E. S trauss a vailable a t ht tp://www.faculty.biol.ttu.edu/Strauss/Matlab/Matlab.htm (accessed 14 February,
2011).
FIGURE 2. Body (in fluid) of the holotype of M. guaycuru (ALP 9277). Scale b ar = 10 mm. Bellow on the left, the arrow
shows the plagiopatagium attachment.
Qualitative characters: A set of qualitative characters selected by previous authors (e.g., Thomas 1901; 1902;
Miller & Allen 1928 ; Hand ley 1960; LaVal 1973; B aud & Menu 19 93; López-González et al. 2 001; LópezGonzález 2005; Moratelli 2008; Wilson 2008) was used to characterize the available samples of M. simus, as follows: point of insertion of the plagiopatagium (attached at toes by a narrow band of membrane or at ankles); position of P3 (aligned with other premolars or displaced to the lingual side, and visible or not visible when observed in
lateral view); occurrence and hei ght of sagi ttal crest (absent or present, and hei ght: very low, low, medium and
high); occurrence and hei ght of occipital crests (absent or present, and height: very low, low, medium and high);
shape of the braincase roof (parietal inclined forward or straight); shape of the occipital region (occipital flattened
when obser ved in l ateral vi ew, bei ng not pr ojected m uch beyo nd the limit of occi pital condyles, or occipital
rounded, being project beyond the limit of occipital condyles). Capitalized colors nomenclature follows Ridgway
(1912).
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Results
The holotype of M. guaycuru and qualitative comparisons. The holotype of Myotis guaycuru is an adult female
specimen (ALP 9277), preserved in fluid, with the skull and mandible complete (Figures 2 and 3). The skin is torn
on the abdominal region and hairs are lacking in a great part of the abdominal and lumbar regions. The holotype is
a medium-sized specimen (FA 38.1 mm; GLS 13.6 mm), with extremely short and woolly fur (LVH and LDH, 3.6
and 3.8, respectively). Bases and tips of hairs in dorsal and ventral pelage are of similar color, the dorsum of uropatagium is almost naked, and the plagiopatagium is attached at the level of the ankles. The skull lacks a sagittal
crest, the interorbital constriction is wide and the rostrum is short and wide. The P3 is smaller and displaced to the
lingual side i n relation to other pr emolars. C onsidering the se traits, mai nly the plagiopatagium attached at th e
ankles and the extremely short fur, the holotype of M. guaycuru differs from the type specimens of all South American forms, with the exception of M. simus. Apart from the lack of sagittal crest, none of the above characters can
be used to distinguish the holotypes of M. guaycuru and M. simus. Although the sagittal and occipital crests have
been used by Proença (1943) to distinguish those species, as discussed bellow, these structures have a great range
of variation in M. simus, not allowing their use as diagnostic characters.
Quantitative variation in M. simus. Due to small sample sizes, to avoid redundancy matrices, only 10 skull
measurements sampling distinct regions of the skulls and mandibles (GLS, MAB, BCB, IOB, POB, BAC, BAM,
MTL, M13 and MAN) were selected for the multivariate geographic analyses.
Principal Component Analysis͗The 1st principal component (PC1), which accounted for 77% of the total craniometric variation, is regarded as a general size axis based on the positive and high magnitude loadings of all variables. Regarding measurements of the width (MAB, BCB , IOB, POB, BAC and BAM) an d length (GLS, MTL,
M13 and MAN) of skull, PC1 scores show that the Bolivian sample (sample 1) is larger than the Peruvian samples
(samples 8 and 9), with intermediate values, and Amazonian samples (samples 2, 3 and part of 4), with the lower
values. The score of the holotype of M. guaycuru (sample 6) reveals that this specimen is similar in size to Amazonian specimens. PC2 scores are not informative on the distinction of samples (Figure 4; Table 1).
TABLE 1. Vector correlation coefficients (“loadings”) between original variables and principal components (PC1 and
PC2) and between original variables and canonical variates (CV1 and CV2) for South American samples of M. simus.
Numbers in bold indicate vector correlations with magnitudes larger than ʳ0.29ʳ.
Loadings of PCA and CVA
Characters
PC1
PC2
CV1
CV2
Greatest length of skull (GLS)
0.85
0.24
-0.44
0.44
Mastoid breadth (MAB)
0.95
0.14
0.42
0.07
Braincase breadth (BCB)
0.85
0.41
0.34
-0.63
Interorbital breadth (IOB)
0.92
0.07
-0.36
0.05
Postorbital breadth (POB)
0.74
0.43
0.13
0.09
Breadth across canines (BAC)
0.84
-0.45
-0.10
-0.09
Breadth across molars (BAM)
0.87
-0.38
0.02
0.30
Maxillary toothrow length (MTL)
0.91
0.15
-0.05
0.09
Molariform toothrow length (M13)
0.93
-0.11
0.11
0.25
Mandibular toothrow length (MAN)
0.94
0.10
0.59
-0.48
Canonical Variate Analysis͗The 1st and 2nd canonical variate axes (CV1 and CV2) respectively accounted for
82% and 15% of the variation among largest geographic samples. In relation to the first axis, scores of the Bolivian
sample (sample 1) are co mpletely di stinct from t hose of Amazonian samples ( samples 2, 3 and 4 ). C V2 s cores
mainly separate the three Amazonian samples. A contrast between GLS and MAN, as w ell as between IOB and
MAB characterizes distinction along CV1, wh ereas a co ntrast bet ween G LS and BC B characterizes distinction
along CV2 (Figure 5; Table 1).
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FIGURE 3. Dorsal, lateral and ventral views of the skull and mandible of the holotype of M. guaycuru (ALP 9277). Scale bar
= 5 mm. The distance between the dentary bones is reduced due to the disarticulation of the mandibular symphysis.
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MORATELLI ET AL.
FIGURE 4. L eft ( a): M ultivariate in dividual sco res o f d ata in th e two f irst p rincipal co mponents fo r sam ples o f M. simus
labeled by locality — (1) Cercado, Beni, Bolivia; (2) Borba, Amazonas, Brazil; (3) Manaus, Amazonas, Brazil; (4) Parintins,
Amazonas, Brazil; (5) El Refugio, Santa Cruz, Bolivia; (6) Salobra, Mato Grosso do Sul, Brazil (type specimen of M. guaycuru) (7) Rio Juruá, Amazonas, Brazil; (8) Ucayali, Loreto, Peru; and (9) San Juan, Pasco, Peru. Right (b): Corresponding vector
correlations (greater than ʳ0.29ʳ) of craniometric characters with the first two eigenvectors.
FIGURE 5. Left (a): Multivariate individual scores in the first two discriminant axes on the discriminant function for the four
largest samples of M. simus labeled by locality — (1) Cercado, Beni, Bolivia; (2) Borba, Amazonas, Brazil; (3) Manaus, Amazonas, Brazil; (4) Parintins, Amazonas, Brazil. Right (b): Corresponding vector correlations (greater than ʳ0.29ʳ) of craniometric characters with the first two eigenvectors.
A Mantel test did not detect a significant correlation between geographic and morphologic distance matrices (r
= 0.63; p = 0.125). This result suggests that the morphometric divergence between Bolivian and Amazonian samples cannot be explained by the geographic distance between them.
Allocation of small samples: A pattern more congruent with the isolation-by-distance model was revealed by
the probabilistic allocations of smaller to larger samples, with most small samples allocated to nearby larger ones.
The specimen from Rio Juruá (Amazonas, Brazil) was mainly allocated to the Amazonian samples (97%). SpeciGEOGRAPHIC VARIATION IN MYOTIS SIMUS
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47
mens from San Juan (Pasco, Peru) and Ucayali (Loreto, Peru) were mostly allocated to Amazonian samples (100
and 90%, respectively), whereas the specimen from El Refugio (Santa Cruz, Bolivia) was allocated to the Bolivian
sample (91%) (Table 2). An exception to this allocation pattern was found for the holotype of M. guaycuru, from
Mato Grosso do Sul, Brazil, which was not allocated to the Bolivian sample, as would be expected on geographical
grounds, but to Amazonian samples in 100% of 1,000 bootstrap iterations (Table 2). The classification of Proença’s
type specimen to Amazonian samples may be explained by its narrower skull base, which resembles the condition
of the maj ority of Amazonian and Peruvian speci mens, th e latter i ncluding to potypes of M. simus. In contrast,
Bolivian specimens generally have mastoids more laterally projected.
TABLE 2. Frequency distribution of classification of single specimens using the minimum Mahalanobs distances to the centroids of
remaining samples based on 1,000 bootstrap iterations. Bold values correspond to higher classification values.
Large samples
Small samples
Cercado
Borba
Manaus
Parintins
El Refugio
0.91
0.05
0.03
0.01
Salobra
0
0.65
0.17
0.17
Rio Juruá
0.03
0.02
0.95
0
Ucayali
0.10
0.03
0.10
0.77
San Juan
0
0.06
0.04
0.90
TABLE 3. Measurements of the holotype of M. guaycuru and summary of measurements (mm) and weight (g) for two samples
of f emales o f M. simus. F-statistics an d ass ociated p robability fro m o ne-way analyses o f v ariance (ANOVAs) for th e n ull
hypothesis of equality of means for skull measurements of two samples of M. simus. Significant values are in bolt.
Myotis
guaycuru
Pooled Amazonian samples:
Borba, Manaus and Parintins
(Amazonas, Brazil)
Bolivian sample: Cercado
(Beni, Bolivia)
Characters
Holotype
Mean
(Range)
N
Mean
(Range)
N
F
p
FA
38.1
38.1
(35.5–39.7)
16
39.4
(38.5–40.7)
13
–
–
3MC
35.6
34.9
(33.1–36.5)
16
36.3
(35.3–37.9)
13
–
–
THL
6.2
5.9
(4.7–6.6)
16
5.9
(5.5–6.5)
13
–
–
LDH
3.8
3.9
(3.1–4.7)
15
4.5
(3.4–5.4)
13
–
–
LVH
3.6
3.4
(3.0–4.0)
15
3.7
(2.9–4.4)
12
–
–
–
ANOVAs
Weight
–
10.3
(9.0–10.8)
12
–
–
GLS
13.66
14.05
(13.57–14.59)
19
14.62
(13.93–14.99)
27
52.438
<0.001
CCL
12.17
12.36
(11.87–12.85)
18
12.94
(12.42–13.31)
27
67.904
<0.001
CIL
13.01
13.23
(12.75–13.73)
19
13.93
(13.31–14.28)
27
86.736
<0.001
BL
11.55
11.82
(11.18–12.23)
19
12.4
(12.10–12.69)
20
63.408
<0.001
ZB
8.83
9.05
(8.93–9.18)
3
9.93
(9.61–10.23)
11
53.604
<0.001
MAB
7.43
7.47
(7.26–7.64)
17
8.21
(7.97–8.46)
27
324.753
<0.001
BCB
7.03
6.94
(6.67–7.27)
18
7.38
(7.06–7.71)
27
90.266
<0.001
IOB
4.86
4.74
(4.57–4.97)
19
4.8
(3.91–5.28)
27
0.33
0.569
POB
3.9
3.82
(3.63–3.96)
19
4.03
(3.79–4.34)
21
33.006
<0.001
BAC
3.86
4.01
(3.67–4.27)
17
4.22
(3.98–4.41)
27
23.992
<0.001
BAM
5.53
5.69
(5.28–5.98)
19
6.08
(5.82–6.35)
27
58.367
<0.001
MTL
5.03
5.03
(4.86–5.19)
18
5.37
(5.14–5.58)
27
110.41
<0.001
M13
2.95
2.94
(2.72–3.11)
19
3.2
(3.08–3.32)
21
103.612
<0.001
MAL
9.98
10.16
–
1
10.77
(10.21–11.83)
18
3.35
0.085
MAN
5.16
5.4
(5.19–5.54)
18
5.77
(5.48–5.97)
25
111.795
<0.001
Summary statistics: N = sample size. See text for a description of measurement methods.
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MORATELLI ET AL.
Measurements summarized on Table 3 revea l that the Bolivian sample is larger than Amazon samples in all
characters, the majority being statistically significant (except IOB and MAL). Among cranial measurements, two
better distinguish Amazon and Bolivian samples, the zygomatic breadth (ZB) and the mastoid breadth (MAB).
Qualitative variation in M. simus. The majority of Bolivian specimens have more laterally projected mastoid
processes, a condition present i n few specimens from Amazoni an and Peruvian samples (Figure 6), resulting in
larger averages for the mastoid breadth (see Table 3). In few specimens of these samples considerable variation in
the co lor of f ur was recorded, t he d orsal and vent ral pe lage of o ne B olivian sp ecimen ( USNM 584502) b eing
Ochraceous-orange, while the dorsal pelage of central and western Amazonian specimens being Tawny, Russet or
Cinnamon-brown, and the ventral pelage Ochraceous-tawny or Buckthorn-brown (USNM 364482, AMNH 76252,
AMNH 91414). The frequency of distribution of other qualitative characters analyzed did not reveal consistent differences among samples (Table 4).
―
―
FIGURE 6. Dorsal view of the skulls of two specimens of M. simus: A from Santa Cruz, Bolivia (USNM 584502), B from
Pasco, Peru (USNM 364482). Scale bar = 5 mm.
Description of M. simus. The holotype of M. simus is an adult female (BMNH 8.5.12.2), preserved in fluid,
with skull and mandible cleaned, collected by W. Davis in 1876 in Río Ucayali, Loreto, Peru, altitude of 100 m
(06°44’S, 75°06’W) (Thomas 1901; LaVal 1973; Carter & Dolan 1978). The f ollowing descr iption is base d on
photographs generously provided by L. Tomsett (BMNH): the skull and mandible are complete, with the exception
of the zygomatic arches, in which both jugal and squamosal processes are broken (Fig. 7). The rostrum is short and
wide, the P3 is lingually displaced, being smaller than the P2, the sagittal and occipital crests are present, the pari-
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etal is inclined forward and the supraoccipital region is flattened in lateral view, not projected much beyond the
posterior limit of occipital condyles (Fig. 7). According to Thomas’ (1901) description, the pelage is short and the
plagiopatagium is attached at ankles.
TABLE 4. Occurrence and distribution of sel ected qualitative characters in M. simus for Bolivian (group 1) and pooled Amazonian
(groups 2, 3 and 4) samples.
Sample 1
(Bolivia)
Samples 2, 3 and 4
(Amazon)
Characters
N
(%)
N
(%)
P3 (position regarding other premolars)
Ntotal = 23
Displaced and not visible in lateral view
1
(4.3)
3
(9.1)
Displaced and visible in lateral view
0
(0.0)
0
(0.0)
Aligned and not visible in lateral view
21
(91.3)
24
(72.7)
Aligned and visible in lateral view
1
(4.3)
6
(18.2)
Sagittal crest (occurrence)
Ntotal = 23
Absent
1
(4.3)
1
(2.7)
Present
22
(95.7)
36
(97.3)
Sagittal crest (height)
Ntotal = 22
Very low
8
(36.4)
10
(28.6)
Low
6
(27.3)
1
(2.9)
Medium
8
(36.4)
5
(14.3)
High
0
(0.0)
19
(54.3)
Occipital crests (occurrence)
Ntotal = 23
Absent
0
(0.0)
1
(2.7)
Present
23
(100)
36
(97.3)
Occipital crests (height)
Ntotal = 23
Very low
4
(17.4)
Low
7
(30.4)
8
(23.5)
Medium
11
(47.8)
14
(41.2)
High
1
(4.3)
10
(29.4)
Braincase roof (shape)
Ntotal = 23
Parietal straight
3
(13.0)
5
(14.7)
Parietal inclined forward
20
(87.0)
29
(85.3)
Occipital region (shape)
Ntotal = 23
Occipital rounded
0
(0.0)
5
(14.7)
Occipital flattened
23
(100)
29
(85.3)
Plagiopatagium (point of insertion)
Ntotal = 17
At ankles
0
(0.0)
5
(17.2)
At toes by a narrow band of membrane
17
(100)
24
(82.8)
Ntotal = 33
Ntotal = 37
Ntotal = 35
Ntotal = 37
Ntotal = 34
2
(5.9)
Ntotal = 34
Ntotal = 34
Ntotal = 29
Based on the series available for the present study, M. simus can be described as follows: a medium-sized species (FA 35.5–39.7 mm; weight 5–10 g) compared with other South American Myotis; ears small (11–13 mm); plagiopatagium attached at toes by a narrow band of membrane (78%) or at ankles (22%); short and woolly pelage;
length o f dorsal ha irs r anging f rom 3 t o 5 mm; col or o f dorsal pe lage va rying be tween Ochace ous-orange an d
Sudan-brown, without contrast between bases and tips; length of ventral hairs varying from 3 to 5 mm and slightly
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MORATELLI ET AL.
FIGURE 7. Dorsal, lateral and ventral views of the skull and mandible of the holotype of M. simus (BMNH 85.5.12.2). Scale
bar = 5 mm. Photographs provided by Roberto Portela Miguez (The Natural History Museum, England).
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51
bicolor; plagiopatagium and uropatagium Cinnamon-brown; fringe of hairs along the trailing edge of the uropatagium absent; skull moderate in total length (GLS 13.5–15.0 mm), with a well-marked interorbital constriction in
dorsal view. In lateral view, the parietal is generally inclined forward (88%) and the supraoccipital region is flattened (89%); sagittal crest generally present (86%) and very low (25%), low (17%), medium (24%) or high (34%);
occipital crests always present (100%) and very low (8%), low (32%), medium (36%) or high (24%); P3 generally
in toothrow (91%), not visible (73%) in lateral view. For field identification the most relevant characters are t he
plagiopatagium attached at toes by a narrow band of membrane or at ankles, the extremely short and woolly fur and
the absence of a fringe of hairs along the trailing edge of the uropatagium.
Discussion
Nomenclatural implications. Thomas (1901) and Miller and Allen (1928) used the attachment of plagiopatagium
as a diagnostic character to distinguish M. simus from all other South American forms of Myotis. However, Handley (1960) considered this character an artifact of preparation, and regarded it as usel ess, a decision followed by
LaVal (1973). More recen tly, Baud and Men u (1993) analyzed the insertion of plagiopatagium in live specimens
and ratified its validity in distinguishing M. simus from other species, a f inding reiterated by su bsequent authors
(e.g., López-González et al. 2001; López-González 2005; Moratelli 2008; Wilson 2008). Based on the attached to
the ankles condition of the plagiopatagium, the short pelage and the similar cranial morphology revealed by morphometric a nalyses with r espect t o t he t opotypical series of M. simus, Myotis guaycuru Pr oença, 1943 must be
regarded as junior-synonym of Myotis simus Thomas, 1901, as formerly proposed by López-González et al. (2001).
Variation in M. simus. The multivariate analyses revealed that (1) the Bolivian sample is larger than available
northern samples, which was confirmed by the univariate comparisons; (2) Peruvian and Amazonian samples are
craniometrically similar, whereas the Bolivian sample is the most distinct; finally, (3) the skull of the holotype of
M. guaycuru is more similar to those of Amazonian/Peruvian specimens than to the geographically closer Bolivian
samples. López-González et al. (2001) had found significant differences between northern (northern Brazil, Ecuador and Peru) and southern (Bolivia and Paraguay) samples of M. simus, the first being smaller fo r seven cranial
measurements (condylo-canine l ength, mast oid l ength, braincase breadth, length of t he r ostrum, maxi llary t oothrow length, molariform toothrow length and mandibular toothrow length). Those authors also verified that Bolivian sample was s ignificantly l arger t han a Paraguayan sampl e in f our cranial measuremen ts (mast oid breadth,
braincase breadth, length of the rostrum and maxillary toothrow length).
Based on the morphometric structure r evealed by L ópez-González et al. ( 2001) and the present study, with
Bolivian samples presenting l arger averages t han northern and southern samples, in addition t o different pelage
color and cranial m orphology, w e hypothesize that Bolivian population may con stitute a di stinct species. U nder
this in terpretation, th e h olotype o f M. guaycuru could f ill in a ga p connecting the more similar A mazonian and
Peruvian samples with the Paraguayan sample, at the exclusion of the population from Bolivia. However, considering the absence of specimens f rom Paraguay i n the present analysis, and t he overall rarefaction of intermediate
samples in relation to those from Bolivian and from Amazonian/Peruvian localities, a more definite conclusion in
this r egard m ust be postponed. Together wit h mor e compr ehensive morphological sampl es, molecular st udies
addressing the genetic variation of samples should help in evaluating this hypothesis.
Finally, if future analyses confirm distinction of the Bolivian population, in order to formally recognize it a
new name should be proposed, as the holotype of M. guaycuru was found to be morphometrically more similar to
the Amazonian/Peruvian samples, this last including a topotypical series of M. simus.
Acknowledgments
Celia López González (Instituto Politécnico Nacional, Durango, Mexico) kindly made available data about the Paraguayan specimens of M. simus; we op ted not to include them in the m orphometric analyses, as measurements
could not be conf idently associ ated w ith our s, as they have been t aken und er a di stinct pr otocol by a dif ferent
researcher. T he following curat ors and col lection staff prov ided access t o specimens under t heir care: Leandro
Salles, Luiz Flamarion Oliveira and Stella Maris Franco (Museu Nacional, Brazil), Fernando de Camargo Passos
(Universidade F ederal do P araná, Brazil), Teresa C ristina C . Margarido (Museu d e H istória N atural C apão da
52 · Zootaxa 2985 © 2011 Magnolia Press
MORATELLI ET AL.
Imbuia, Brazil), Mario de Vivo, Juliana Barros (Museu de Zoologia da Universidade de São Paulo, Brazil), Eliana
Morielle-Versute (Uni versidade Estadual P aulista “Ju lio d e Mesqu ita F ilho”, B razil), Nanc y Si mmons, E ileen
Westwig (American Museum of Natural History, USA), Don Wilson, Linda Gordon (National Museum of Natural
History, USA), Alfred Gardner (USGS Patuxent Wildlife Researche Center, USA) and Patrick Boussès (Muséum
national d’ Histoire nat urelle, Fr ance). R oberto Por tela-Miguez ( The Natu ral Hi story Museu m, England) gener ously provided pictures of the skull of the holotype of Myotis simus. We are grateful to Jane Steele for helpfully
reviewing previous drafts of the manuscript. This work fulfils part of the requirements for PhD degree in Zoology
of RM at Universidade Federal do Rio de Janeiro. RM was partially supported by a scholarship from Coordenação
de Aperfeiçoamento de Pessoal de Ensino Superior (CAPES, Ministério da Educação, Brazil), and by Short-Term
Visitor and C ollection Study grants respectively f rom t he N ational Mu seum of Natural Hist ory ( USA) and th e
American Museum of Nat ural History ( USA). This work was al so supp orted by r esearch f ellowships to JAO
(CNPq 306801/2007-8) and to ALP (CNPq 303622/2009-1).
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Appendix: Specimens examined.
The voucher-specimens examined are deposited in the following institutions: American Museum of Natural History, New York,
USA (AMNH), National Museum of Natural History, Washington DC, USA (USNM), Museu de Zoologia da Universidade de
São Paulo, São Paulo, Brazil (MZUSP) and Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil (ALP). Individuals marked with an asterisk were used in the morphometric analyses. The coordinates were obtained from the skin tags, from
the Gazetteer of Marginal Localities of Gardner (2008) and from the Google Earth Program.
BO LIVIA: Ce rcado, Be ni ( 14°39’S, 64°39’W): A MNH 2 11155, 21 1156, 2 11167*, 2 11168*, 2 11169*, 2 11170, 21 1171*,
211172*, 211173*, 211174*, 211178*, 211179*, 211180*, 211181*, 211182*, 211183*, 211190, 211192*, 211193*, 211194*,
211195*, 211196*, 211197*, 211198*. El Refugio, Santa Cruz (14°45’S, 61°02’W): USNM 584502*. BRAZIL: Borba, Amazonas (06°53’S, 52 °02’W): A MNH 91 886, 91 887, 9 1888*, 91 889*, 918 90*, 9 1891, 91892, 94 224, 94 225, 9 4227, 94230,
94231, 9 4232, 942 33*, 9 4234*. I tacoatiara, Amazonas (03°08’S, 5 8°26’W): MZ USP 34 72. M anaus, A mazonas (0 1°4’S,
63°36’W): AMNH 79534, 91472, 91473, 91474, 91475*, 91476*, 91477*, 91478*, 91500*. Parintins, Amazonas (02°38’S,
56°44’W): 92983*, 93489, 93490*, 93491, 93492*, 93493*, 93494*, 93495*, 93496*, 93497, 93922*, 93923*, 93924, 93925.
Rio Juruá, Amazonas (04°48’S, 68°67’W): MZUSP 638, 1074*. Taiamã, Mato Grosso (16º48’S, 57º28’W): MZUSP 13815.
Salobra, Mato Grosso do Sul (21°58’S, 56°31’W): ALP 9277*. Localidade desconhecida: MZUSP 1062. ECUADOR: Pastaza,
Quito (1º27’S, 76º40’W): AMNH 71483, 71485, 71486, 71487, 71488, 71490, 71491, 71492, 71493, 71494 PERU: Maynas,
Loreto (03°19’S, 72°07’W): AMNH 74105, 74109, 74110, 74378, 74379, 74380, 74381. Ucayali, Loreto (06°44’S, 75°06’W):
AMNH 76 240, 76 241, 76 242, 76 243, 762 44*, 76245, 76246, 76 247, 76 248, 76 249, 76 252*, 76253*. S an Jua n, Pasco
(10°30’S, 74°53’W): USNM 364481*, 364482*.
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