ZooL J. Linn Soc., 2343. With 8 figures
January 1975
Land nernertines of Australia
JANET MOORE
Department of Zoology. Downing Street, Cambridge
Accepted for publication June I974
An account of the distribution of Australian land nemenina includes new specimens found in
Queensland and near Canberra. Characters uniting Australian Geonemertes and distinguishing
between G. australiensis, G. hillii and G. dendyi are redefined. A new species G. stocki is
described and related to the other three species.
CONTENTS
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Introduction
Specimens found in 1972
The distribution of Australian Geonemertes . . .
Characters uniting the Australian species
Characters distinguishing between the Australian species
G. stockisp. nov.
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Conclusions
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Acknow1edgements
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References
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INTRODUCTION
The genus Ceonemertes consists of about a dozen species all occurring only
on oceanic islands or in Australia and New Zealand. The “genus” appears to be
a convergent assembly of forms separately evolved from marine ancestors
(Pantin, 1961, 1969). There are three groups of species occurring respectively
on Indo-pacific islands (the “Pelaensis” group), in Australia and in New
Zealand. Three separate species (which do not constitute a group) occur on
Atlantic islands (Moore & Moore, 1972). Further study of land nemertines is
needed to trace their interrelationships and their parallel adaptations to the
terrestrial habitat.
The Australian group has been described as three species with distinctive
characters common to all three:
G. australiensis (Dendy, 1892) from Victoria and Tasmania,
C. dendyi (Dakin, 1915) from Western Australia,
G. hillii (Hett, 1924) from New South Wales.
All occur in similar damp woodland habitats which may be far from the sea.
The widely separated localities of these species and the great range of
23
24
J . MOORE
intraspecific variation revealed in Tasmanian G. australiensis by Hickman
(1963)prompted a visit to Australia in search of land nemertines. The search
was concentrated: (a) in the rainforests of Queensland, geographically
intermediate between New South Wales (G. hilliil and New Guinea (G.
pelaensis). N o land nemertine had ever reported from Queensland; (b) in
the Brindabella hills near Canberra, A.C.T., geographically intermediate
between the localities of G. hillii and G. australiensis, where an unidentified
land nemertine had once been found by Dr Ross Pengilley. Thanks to the
kindness of the Australian Museum, Sydney, and of Dr E. Riek, C.S.I.R.O.
Canberra, I was able to section and examine Geonemertes specimens previously
collected in eastern Australia.
The present paper reports:
1. The specimens found in 1972.
2. The known distribution of Australian Geonemertes.
3. The distinguishing features of the three previously described Australian
species G. australiensis, G. hillii and G. dendyi (their common characters
are given by Pantin (1969)but the differences between them need now t o
be redefined).
4. The description of a new species found during the search, which is named
G.stocki in honour of the finder.
SPECIMENS FOUND IN 1972
In Australia as in other parts of the world, land nemertines are very local in
occurrence. They require shade and shelter, protection both from desiccation
and from flooding, from frost and from heat. They are found in rotting wood
(damp but not wet enough for extensive fungal growth) or (more easily) on the
underside of large stones, typically about If ft (0.5m) across, under which
there is good soil or leaf litter and plenty of associated fauna. Many habitats
which support land planarians are not suitable for nemertines (in the field the
two phyla can only be distinguished with certainty when mechanical irritation
stimulates the eversion of the nemertine proboscis).
Table 1 below shows the specimens found in July and August 1972.
THE DISTRIBUTION OF AUSTRALIAN GEONEMERTES
G. dendyi was found by Dakin in 1914 in a valley near Armadale, about 19
miles southeast of Perth in the Darling Ranges. In 1946 Mr A. G. Nicholls
found a further specimen for Dr Pantin, very close to Dakin’s type locality
(about 3 mile (1.2 km) N.E. of the Narrogin Inn, Armadale, under a small log
in wet meadowland in a cleared field). Subsequently Mr J. A. L. Watson found
a specimen in August 1955 a t Walebing, Western Australia.
Liners leaving Fremantle had Plymouth as their first port of call, and English
imports included Australian flowers and woods. Perhaps in this way C.dendyi
became introduced to western areas of Britain where it is quite widely
dispersed (Pantin, 1944,1961). I t has also been found in European greenhouses
(Stammer, 1934), in Sad Miguel, Azores (Moore & Moore, 1972) and in Gran
E. Rick
N. W. & J. M.
searched but found none
Mr R. Ceppert & J. M.
Mr J. Monlock & J. M.
h R. Peagilley & Mr J.
Monlock (specimen in
Australian Museum)
B. Smith
J.
Prof. A. Stock & J. I
Aug. 1943
JUL-Aug.
1972
Aug. 1972
Aug. 1972
M y 1963
Aug. 1972
Aug. 1972
Jul. 1972
M.
N. W. & J. Moore (J. M.)
Jul. 1972
Queensland, Lamington Nr. O’Reilly’s.
3 specimens (within a mile) under
stones beside paths through thick
rain forest including Norhofagus,
c. 3200 ft (960m)
Queensland, Lamington Nr. Binna
Burr?. 10specimens. Underside of
loose rocks by E. Canuogra Ride,
just below Fountain Falls
N. Queensiand Rain forest areas
including Mount Spec near
Tomsville. woods beside Palmerston
Highway, Lakes Barrine & Eacham,
and elsewhere on Atherton Tableland,
Mission Beach, Dunk Island
Brindabella hills, Canberra 2 specimens
under stones at edge of clearing by
Condor Creek, 1 mile (1.6km) above
road bridge
Brindabella hills, Canberra 7 miles
beyond piccadilly Circus at edge of
Snowy Flat (c. 4000 ft.) ( 1200 m)
under log at boundary between wet
and dry sclerophyll
Yicroria, Mount St. Leonard, 5 miles
N. of Healesville c. 3300 ft (990m).
2 Specimens
Vlcrorh, Badger C m k nr. Healesville,
under stones in wet sclerophyll.
c. lo00 ft (300m). 2 specimens
Point Lookour. New England
National Park nr. Armidale, N.S.W.
5250 ft (1575 m)
Locality
l’specimen. dark brown dorsally.
white ventrally. Spontaneous
fragmentation from posterior end.
Only c. 9 mm long
30 mm
7 scarlet specimens
Exactly as described above for
Brindabella specimens
21 and 28 nun
4 similar specimens, yellowish buff
with broad brown stripe in dorsal
midline.
Brown stripe dark and continuous
in posterior third: anteriorly paler
and mottled.
30-35 mm
G. ausnaliensis, all alike and typical
These three colour varieties have all
been found by Hickman in Tasmania
(a) Reddish brown with pale lateral
stripes (length 20 mm)
(b) Dark brown all over (1 1 mm)
(c) Lemon coloured with dark dorsal
stripe and black “head” (42mm)
Adults bright dark red with lateral
borders of lighter colour. Young
mottled grey. then lateral red stripes
appear
G. stocki sp. nov.
G. Uii (frequently found here)
G. ausrraliensisconfirmed by
histological examination
C.ausnaliensis All four specimens
were sectioned: alike and typical
G. hillii
Suggested by colour, confirmed by
histological examination
Identification (by J.M.)
External appearance
Table 1. Specimens of Geonemertes found in the field during the 1972 visit
(and previously unidentified specimens examined in 1972)
J. MOORE
26
Canaria in 1972 (P. Brinck, pers. comm.). I t has never been found on the
eastern side of Australia (there was less shipping contact between west and east
than between Western Australia and Europe) nor is there any record of the
eastern Gmnemertes species outside Australia.
G. hillii was first found by J. P. Hill near Barrington Tops, New South
Wales-“from the scrub about a mile down the Barrington River, N.S.W. It is
not uncommon under logs if the soil is good” (Hett, 1924). The conspicuous
red colour is described. Professor Stock has found many specimens in the
country nearby:-“We found G. hillii in a locality (Point Lookout) at an
altitude of about 5000 ft in a relatively dry situation. Since then we
have found it near a place called Dorrigo (Dorrigo National Park) at an altitude
of 2400 ft and at the edge of a rain forest and lately at the foot of
Dorrigo Mountain, at 500 ft in subtropical rain forest on the upper
reaches of the Bellinger river (Bellinger River, North arm). This extends the
range to the east to the edge of the coastal plain and fits in with Fletcher’s
(1891) find in a similar situation on the Richmond river. The crest of the
mountain chain along the eastern coast of New South Wales seems, as far as we
know at present, to be the limit to the west of the distribution of G. hillii“.
(letter to J.M., February 1968).
Fletcher (1891) recorded a land nemertine “brownish orange except for a
lateral band each side” from the Richmond River. In 1895 he recorded the
collection of specimens from Gosford “richer darker red even than Geopfanu
sangttiitea which it otherwise resembles”. This certainly sounds like G. hillii,
and in this paper he refers to the Richmond River find as “similarly deeply
pigmented” (Fletcher, 1895) despite his original description of it as “brownish
orange”. There is a tube of Fletcher’s Geoneinertes in the Australian Museum,
containing four specimens labelled by Fletcher “Dunoon, N.S.W., and
Tasmania” (Dunoon is on the Richmond River). Three of these specimens are
definitely G. atrstralierisis, one is uncertain, and there is no way of
distinguishing the Richmond River specimen.
Of much greater interest is Dr E. Riek’s 1943 find of G. hillii on the
Lamington plateau (Table 1). This part of Queensland is geographically
continuous with the hills of eastern New South Wales (see map, Fig. 1).
G. australiensis
v I C T O R I A : Dendy’s original find “on a trip to Walhalla” (Dendy, 1889)
was in a narrow valley with steep hills around, in North Gippsland, Victoria. He
first found this nemertine under stones “while hunting about on the hillside
just above one of the tramways”. Further sites in Victoria were later recorded
(Dendy, 1892) many of which have since been swallowed up in the growth of
Melbourne. Specimens found by Spencer from near Lake Victoria, South
Gippsland in July 1891 and from Warragul in September 1892 are preserved in
the National Museum of Victoria. (See also Table 1 for 1972 finds.)
T A S M A N IA
:
G. australiensis was here relatively abundant but many
localities are now rapidly being laid bare. Hickman (1963) examined over 560
specimens and gives a full account of their distribution and variation in colour
and length (up to 84 mm). Earlier records are given by Spencer (1892, 1895),
Fletcher (1891) and Steel (1926), two of whose specimens from the Australian
LAND NEMERTINES OF AUSTRALIA
27
Figure 1. The distribution of land nemertines in South-eastcrn Australia. X. G. ousrraliensis; H.
G.hi//ii;S.G. srorki sp. nav. Stippled area (over 3 0 0 0 ft (900m)) shows the Dividing Range.
Museum were sectioned and confirmed as G. australiensis. No other species of
Geonemertes has been found in Tasmania.
N E w so u T H w A L E s : and A.C.T.: G. australiensis has been found in the
Brindabellas (Table 1) and from Pretty Point on the plateau of Mount
Kosciusko, source of the Murray River (Fletcher, 1895). Fletcher’s two
Kosciusko specimens were described as lacking red colour and were found in a
tube by themselves in the Australian Museum. Sectioning confirmed the
identification.
28
J . MOORE
u u E E N s L A N 1) : ti. australiensis was found on the Lamington plateau, in
colour varieties previously reported only from Tasmania (Table 1).
(:HARACTERS UNITING THE AUSTRALIAN SPECIES
The basis of the above identification of specimens must now be defined. A
full description of the structure of G. australiensis was given by Dendy (1892)
but the original accounts of G. dendyi and G. hillii were incomplete. A survey
“The Genus Geonemertes” by the late Professor Pantin (1969) was prepared
by the present author for posthumous publication. The characters uniting these
three Australian species are there fully discussed and illustrated and will
therefore only be summarised here. G. stocki sp. nov. (see below) shares all
these common “Australian” characters.
Characters of Australian Geonemertes shared by some
(but not all) other species of’Geonemertes
(a) The cephalic gland discharges mucus by many extemporised openings
near the anterior tip of the body. N o frontal organ occurs.
(b) The only cephalic furrow is a transverse ventral groove into which the
cerebral organs open.
(c) The cerebral organ consists of a short cerebral canal which forks between
an anterior sac and a ganglionic region from which a nerve leads to the
dorsal cerebral ganglion. From the end of that branch of the duct in the
ganglionic region, a large posterior gland extends behind the brain.
(d) Acidophilic dorsal gland cells are prominent in the parenchyma,
especially anteriorly.
(e) The proboscis is massive, and is used as a locomotor organ for quick
escape. The proboscis sheath muscle is in the form of wickerwork rather
than separate longitudinal and circular layers. There is a large and
variable number of proboscis nerves.
(f) There is an accessory lateral nerve arising from the dorsal cerebral
ganglion and running back along the dorsal surface of the main lateral
nerve derived from the ventral cerebral ganglion.
(g) Two vascular plugs project into the rhynchocoelic fluid inside the
proboscis sheath. They are borne on the two anterior branches of the
dorsal blood vessel.
(h) Numerous simple flame cells lead into a very extensive system of
excretory ducts which branch throughout the body in the subdermal
layer and open on the surface by many thousand pores.
(i) The mid-ventral gut caecum (which underlines the pylorus, posterior to
the stomach) is continued forwards as two anterior diverticula, which
end blindly behind the brain.
(j) The animals are oviparous.
Characters of Australian Geonemertes
shared only with New Zealand species
(a) Throughout the body there is a subdermal capillary network, much
branched and with characteristic valves at frequent intervals. This
LAND NEMERTINES OF AUSTRALIA
29
network in the head forms the anterior origin of the two lateral blood
vessels and the two plug-bearing cephalic vessels which unite to form the
dorsal blood vessel: more posteriorly the network forms cross connections between the main vessels in place of the usual quasi-metameric
vascular commissures.
(b) The final region of the excretory ducts is a highly specialised glandular
duct, thick-walled with radial striations in the cytoplasm.
New Zealand Geonemertes differ from the Australian species in eye number, in
lacking dorsal gland cells, and one species (G. novaezealandiae) in having no
accessory lateral nerve. Land nemertines of New Zealand have been described
separately (Moore, 1973).
Character unique to Australian Geonemertes
There is extreme multiplication of the four primitive hoplonemertine eyes:
between 20 and 180 eyes are distributed over the anterior tip of the worm,
usually in four distinct groups.
8
CHARACTERS DISTINGUISHING BETWEEN THE AUSTRALIAN SPECIES
While Pantin’s definition of characters common to t.he three Australian
species remains unaltered, his distinctions between the species must be revised
now that more specimens of G. australiensis and G. hillii have been examined.
(i) G. dendyi is distinct from the other two species in:
(a) Colour pattern. I t is cream coloured with two brown dorso-lateral
stripes (in the field it can be confused with the planarian Rhynchodentus unless the eyes are visible or the proboscis everted).
(b) Size I t is considerably smaller than the other two species (see Table 2).
Possibly in consequence of this there are fewer eyes, fewer proboscis
nerves, fewer stylet sacs and the body wall musculature is less strongly
developed. There are fewer dorsal gland cells (a character less likely to
be size-related).
(c) The posterior gland of the cerebral organ extends backward in a
position lateral to the brain (Fig. 2) instead of ventrally beside the gut
(Dendy’s “oesophageal organ”, fig, 3). Out of 20 specimens of G.
australiensis however one immature specimen has the gland in a
position similar to that of G. dendyi.
(d) Hermaphroditism C.dendyi is a protandrous hermaphrodite. It is now
clear that this is a distinguishing feature. Examination of large numbers
of G. hillii by Stock (pers. comm.) establishes that the sexes are
separate: this is even shown in a constant colour difference. Similarly
for G. australiensis: Hickman (1963) examined 21 1 mature specimens
(75 male, 136 female) and none was hermaphrodite.
(ii) G. hillii and G. australiensis were separated by Pantin on the following
characters :
(a) Colour pattern.
(b) Number of eyes.
30
J . MOORE
+
Network
Cerebral
Cephalic vascular
system
Position of
vascular plugs
0
Cerebral
Network
++
0
Long
Medium
++
++
Small
Ventral
Lateral
11-15
11-21
d 12-60 mm
0 12-84 mm
Q d 3-5 mm
0 4-18 mm
White yellow or brown,
with or without stripes
Cream with 2 brown
stripes
Body musculature
posteriorly
Anterior caecal
diverticula
Spontaneous
fragmentation
Accessory lateral
nerve
Posterior gland
of cerebral organ
Cephalic gland
Proboscis nerves
Sex and size
Colour
-
G.ausrmliensis
C.dendyi
Cerebral
Network
++
0
Short or more
posterior or absent
Large
+
Ventral
18-19
c.30mm
Scarlet with two
stripes
C.hlllii
Table 2. Comparison of the 4 Australian species of G'eonamerfes
Post-cerehral
Loop and network
+++
Medium
t
Ventral
18
(one d. 9.5 mm)
Dark brown dorsally
cream ventrally
G. srocki
C
>z
c
J. MOORE
32
(c)
(d)
(e)
(f)
(g)
Presence or absence of transverse cephalic furrow.
Amount of cephalic gland.
Number of nephridia.
Size of accessory lateral nerve.
Presence or absence of anterior caecal diverticula.
Consideration of each shows that (b) and (c) fail; (d), (e) and (f) are valid
but difficult to quantify and (g) is modified by variation.
(a) Colour. G. hillii is conspicuously scarlet. Two wide lateral longitudinal
bands in the anterior two-thirds of the body are deep red in the
female, orange-red in the male. The dorsal surface between the red
bands and most of the posterior third of the body is purplish brown,
darker in the female. G. australiensis is very variable in colour. I t may
be cream coloured with 1 to 4 dark brown longitudinal stripes, or dark
brown all over, or lemon coloured with a black head (the three
specimens found together at Lamington represented most of these
possibilities) or yellow with a posterior brown stripe as found in the
Brindabellas and in Victoria. Hickman lists a wide range of colour
varieties in Tasmania, noting that large cream-coloured specimens
generally occur only in rain forest and that striped and unstriped
individuals may emerge from the same egg-case. None of the varieties
however is scarlet.
(b) Number of eyes. According to Pantin G. dendyi has 10-20 eyes, G.
australiensis has 40 and G. hillii has 80. The degree of multiplication of
the eyes however varies very widely: it increases during growth and
shows considerable correlation with the size of the worm. Hickman
found only 4 eyes in most newly hatched young G. australiensis,
increasing in the adult to between 39 and 176. Fourteen 1972 adult
specimens show a range from 36 to 61 eyes. Some adult specimens of
G. hillii have as few as 40 eyes. Also the largest G. dendyi found in the
Azores had 29 eyes (not 20). Eye number therefore cannot be a
satisfactory character for separating the species.
(c) Transverse cephalic furrow. G. dendyi and G. australiensis have a clear
ciliated transverse furrow on the ventral surface at the level of the
posterior eye groups. The cerebral organ ducts open ventrally into this
furrow. Some specimens of G. hillii appear to lack this furrow, the
ducts opening directly on to the surface, but in other specimens a
furrow is clear in transverse sections. This therefore fails as a
distinguishing character.
(d) Cephalic gland. Cephalic glands are prominent in all land nemertines.
Typically they are in the form of large lobules of weakly basophilic
cells with small nuclei and small acidophilic inclusions, but occasionally the basophilic lobules are filled with or replaced by large
acidophilic cells with large prominent nuclei (this condition is
characteristic of G. chalicophora, Moore & Moore, 1972). In G.
ausfraliensis (as in New Zealand Geonemerfes) the basophilic lobules
of the cephalic gland are strongly developed and occupy much of the
dorsal and lateral part of the worm from the anterior tip to behind the
brain. More posteriorly (in the pyloric region) there is a small amount
LAND NEMERTINES OF AUSTRALIA
Figure 3. G. australiensis HaJf T. S. post-cerebral region to show abundant cephalic gland, small
acccssory lateral nerve and anterior gut diverticulum reaching to the brain.
3
33
J. MOORE
34
L
1
250pm
Figure 4. G. hillii. Half T. S. post-cerebral region to show sparse cephalic gland with acidophilic
cells, many excretory ducts, large accessory lateral nerve and absence of anterior gut
diverticulum.
of cephalic gland dorsally, consisting of the second type (acidophilic
cells). In G. hillii the cephalic gland is much less well developed.
Basophilic lobules are smaller and fewer, and mainly occur anterior to
the brain. Around the brain and more posteriorly, such cephalic
glandular tissue as there is consists almost entirely of acidophilic cells.
In G. dendyi, some specimens have nearly as much cephalic gland as G.
australiensis.
fe) Number of nephridiu. Nephridial (excretory) ducts are prominent in
sections of all regions of both species. Anterodorsally G. hillii appears
to be particularly rich in nephridia because there is less cephalic gland.
This cannot be quantified as a species-separating character.
(0 The accessory lateral nerve. This nerve is appreciably larger in G. hillii
than in G. austruliensis (and smaller still in G. dendyi). In relation to
LAND NEMERTINES OF AUSTRALIA
35
the area of crosssection of the main nerve, G. hillii has the largest
accessory lateral nerve yet observed in any Geonernertes.
(g) Anterior caecal (gut) diverticula. In C. australiensis these processes are
usually between 200 and and 5 0 0 pm length (about half the length of
the mid-ventral caecum from which they project forward). They reach
forward to the brain (15 specimens) or end close behind it (five
specimens). In G. hillii the anterior diverticula are reported to be
“almost completely absent**.This obtained for three of the specimens
examined but five other specimens had diverticula as long as those of
C. australiensis. In no specimen of G. hillii did they reach forward to
the brain, but ended between 200 and 600pm behind its posterior
surface.
Figures 2, 3, and 4 illustrate the differences between the three
species. With the definitions of C. dendyi, C. hillii and G. australiensis
clearly established, the remaining specimen can be diagnosed as C.
stocki sp. nov.:G. STOCK1 SP. NOV.
Locality
New England National Park, near Armidale, New South Wales. C. hillii
occurs there in dry sclerophyll forest at an altitude of 5250 f t (1575 m), just
below Point Lookout. On 12 July 1972 Professor A. Stock and the author
collected specimens of C. hillii from under logs. Professor Stock included some
leaf litter in the tube: later under the binocular microscope he saw a small
nemertine crawl out.
Methods
The specimen was observed alive by Professor Stock and the author. I t was
then anaesthetised in 9%magnesium chloride for about five minutes and fixed
in 80% ethyl alcohol. I t was sectioned transversely (8 pm) by Mr D. J. Buck at
the Cambridge Zoology Department, and stained in Mallory’s trichrome.
External appearance and behaviour in life
The specimen was uniformly dark brown on its dorsal and dorso-lateral
surface, with abrupt transition to the lateral and ventral cream colour. Two
groups of black eyes could be seen at the anterior end, and regularly repeated
gonads were opaquely white through the cream-coloured portion posteriorly.
That it was a land nemertine became certain when it repeatedly everted a large
proboscis and used it for quick escape movements in the manner common
among Ceonernertes species. I t was a small specimen, about 9.5 mm long by
1 mm across. A unique feature was its repeated spontaneous fragmentation
from the posterior end: a transverse furrow appeared ’on the dorsal surface
about 1 mm. from the posterior end and deepened until the fragment became
constricted off. Five such fragments were formed, approximate millimetre
cubes, dark brown above and cream beneath. At this stage the anterior main
36
J. MOORE
part of the worm was 4.6 mm long (measured from sections) and appeared
bulgy, the proboscis being coiled in reduced space. I t was quickly anaesthetised
and fixed, for fear of disintegration.
Earlier fragmentation cannot be ruled out, but seemed unlikely as the
proboscis retraction after fragmentation might be difficult. No further
fragment was found in the leaf litter.
Fragmentation of the whole nemertine is a characteristic of the freshwater
Potamonemertes (Moore & Gibson, 1973) and has been observed just before
disintegration in C. chalicophora. but controlled serial constriction of the
posterior end is a phenomenon not previously recorded in land or freshwater
nemertines, nor indeed in any other hoplonemertines.
Histological examination of the single specimen
The internal structure can be described under the following headings in order
to relate G. stocki to the other Australian Geonemertes species:Cii aruc ters uniting the A ust ralian species
All these characters, summarised above and more fully described by Pantin
(1969), are found in the present specimen (oviparity must be conjectural: the
specimen is a mature male and shows no sign of developing female organs).
Cliaracters distinguishing bet ween the Australian species
(a) The colour pattern of G. sfocki is distinct from all three.
(b) Size. A mature male of 9 mm length would be very unlikely in G.
dendyi. Males have been found up to 4 mm long and all specimens of
5 m m or more have been female. I t is smaller than any adults recorded
for the other two species: Hickman’s total of 75 male G. australiensis
ranged from 12 to 60 mm in length and there are no records of small
mature G. hillii.
(c) Eyes. There are 30 eyes, in two groups only. The number is not
significant but that there are two groups and not four is very unusual.
(d) The cephalic grclnd The anterior tip has typical basophilic lobules, mainly
dorsal, and acidophilic “dorsal gland cells” are also present. A few basophilic
lobules persist to mid-brain level. Posterior to the ventral cerebral
commissure this form of cephalic gland does not occur, but only acidophilic
gland cells. In this character G. sfocki closely resembles G. hillii, a
resemblance possibly related to occurrence in the same habitat (that land
nemertines occurring in relatively dry habitats should have unusually little
cephalic glandular tissue is unexpected).
(e) The accessory lateral nerve is of the same size in relation to the main
lateral nerve as in G. australiensis. I t has nowhere the large cross-sectional area characteristic of G. hillii, nor is it so small that it becomes
indistinguishable in more posterior sections (as in G. dendyi).
(0 The anterior caecal diverticula reach foward right to the brain, as in G.
australiensis and G. dendyi, and are very long (376 pm, in a small worm
of which the caecum itself is only 344 pm long).
(g) The posterior gland of the cerebral organ lies beside the oesophagus as in
LAND NEMERTINES OF AUSTRALIA
F4gurc 5. C. rtoekl sp. nov. Half T. S. post-ccrcbral region to show one of the vascular plugs,
posterior gland of the cercbd organ, accessory lateral nerve and anterior gut diverticulum.
Cephalic gland h spame. excretory ducts and blood vcssels arc abundant.
37
38
J. MOORE
C. australiensis and C. hillii, not in the dorso-lateral position characteristic of G. dendyi (Fig. 5 illustrates points d, e, f and g).
(h) Other characteristics which have been discussed above:
G. stocki has a transverse ventral furrow into which the cerebral organs
open; the specimen has 18 proboscis nerves; G. stocki has numerous
nephridia in the cephalic region, in the absence of much cephalic gland.
Characters unique to G . stocki
(a) Colour pattern, described above.
(b) Fragmentation, also described above. Four of the five fragments were
sectioned transversely and examined. The sequence and orientation of
the fragments can be deduced from the decreasing size of the accessory
lateral nerve. Towards the edge of each fragment the empty rhynchocoel
becomes occluded and the wickerwork of muscle fibres constituting the
proboscis sheath is much reduced, until only a few fibres remain.
Fragmentation is thus seen clearly in the rhynchocoel, but not in other
structures. Large testes containing mature sperm alternate with lateral
gut caeca in all the fragments, and the acidophilic gland cells occur
dorsally in all but the most posterior one. The posterior tip of the worm
is missing. While the gut curves ventrally as though towards a ventral
subterminal anus, this is not quite reached and no supra-anal nerve
commissure can be seen, although the dorsal blood vessel ends in a
network linking it to the lateral vessels. There is no reason to suppose
that there was ever more than one further fragment.
Incipient fragmentation can be traced in the posterior end of the
main part of the worm. The rhynchocoel is empty for the posterior
1.7 mm (the much coiled proboscis is confined to the anterior 2.9 mm).
1.1 mm from the posterior end, there is a break in the rhynchocoel. The
cavity is occluded and the surrounding proboscis sheath musculature is
reduced to a few fibres (Fig. 6). For 200pm there is no sign of the
proboscis sheath at all and on the dorsal surface transverse constriction is
evidently beginning to fragment a further 1 mm cube. The proboscis
sheath and empty rhynchocoel then reappear. This establishes that
fragmentation of the rhynchocoel precedes the fragmentation of the rest
of the body.
(c) Muscular development posteriorly. The body wall musculature, the outer
circular and in particular the inner longitudinal layer, is unusually well
developed in the posterior region of the animal. The longitudinal muscle
occurs in bundles bounded by connective tissue and these bundles
occupy an unusually large proport,ion of the cross section of the worm
(Fig. 7) both in the fragments and in the posterior half of the main
worm. This muscular development is probably associated with the
process of fragmentation. The dermis (a sub-epidermal layer of connective tissue) is also particularly thick (this layer provides the lattice of
fibres necessary to the worm’s locomotion). The muscular wickerwork
of the proboscis sheath is also well developed, and there are strands of
dorso-ventral muscle. The parenchyma is correspondingly reduced in
quantity.
LAND NEMERTINES OF AUSTRALIA
39
I
I
250pm
Figure 6. G. stocki sp. nov. T. S. at 1 m m from the posterior end to show incipient
fragmentation, with the rhynchocoel already divided.
The muscular development of a land nemertine normally depends
upon its size. This is shown clearly in New Zealand Geonemertes (Moore,
1973), in G. dendyi as opposed to the larger Australian species and
between different specimens of G. hillii and G. australiensis. Anteriorly
(in the precerebral, cerebral and pyloric regions) C. stocki has no more
muscle than a similarly sized specimen of G. dendyi, but posteriorly
there is a marked difference (see Fig. 7), indeed it has more longitudinal
muscle than a specimen of C. hiZlii which is five times its length.
Position of the vascular plugs. Like other Australian Geonemertes. G.
stocki has a pair of vascular plugs which arise on the two anterior
branches of the dorsal blood vessel and project into the rhynchocoel.
These structures are distinctly large for a small worm, being 6 4 ~ m
in
diameter (average size of plugs in five G. hillii is 57 mpm, in fifteen G.
australiensis 55 mpm). What is unusual about them is their position.
Instead of being at the level of the ventral cerebral commissure they are
entirely post-cerebral, at the level of the lateral nerve and anterior caecal
diverticula (Fig. 5). In a single specimen, this might be an individual
variation. Paired vascular plugs have however been examined in six
species of land and freshwater nemertines from New Zealand, in the
three other species of Australian Geonemertes and in G. chalicophora. In
a total of 103 specimens, the structures are at the level of the ventral
j. MOORE
40
A
Figure 7 . A. G. stocki sp. nov. B. G. dendyi. T. S. at 400 Mm from the posterior end to show
the greater muscular development of G. sfocki. Both specimens were between 9 and 10 inm in
length.
LAND NEMERTINES OF AUSTRALIA
41
cerebral commissure or immediately anterior or posterior to it: not one
has post-cerebral vascular plugs.
The cephalic blood system shows a further distinctive character. The
anterior branches of the dorsal blood vessel extend forward from the
plugs in the usual way and then meet in a cephalic vascular loop near the
anterior tip, in addition to forming a very prominent vascular network.
A cephalic vascular loop is a character of most nemertines which lack the
specialisation (confined to Australian and New Zealand land nemertines)
of a capillary network throughout the body. G. aNisonae from New
Zealarid has a vascular loop in place of a network in the cephalic region,
although it has a network more posteriorly (Moore, 1973). C. stocki is
unique in combining the loop with a particularly well developed cephalic
capillary network (Fig. 8 ) .
1
#
250pm
Figure 8. G. stoc# sp. nov. T. S. near anterior tip to show the cephalic vascular loop.
C. stocki sp. nov. is compared with other Australian species in Table
2.
The single Type Specimen is to be deposited in the Pantin collection at
the British Museum of Natural History.
CONCLUSIONS
The distribution of Australian Geonemertes
Negative evidence is not necessarily significant in the search for
Geonemertes. That they were not found in North Queensland does not imply
42
J. MOORE
that they are not there. What the search does reveal is that G'. aitstruliensis is far
more widely distributed than was previously known, and that its wide range of
colour varieties exists outside Tasmania. Interestingly, Southern Queensland (in
a uniform habitat) produced a range of varieties previously reported only from
Tasmania, while the specimens from near Canberra were all identical with each
other and with the many specimens which have been found in Victoria.
G. mstralieiisis and G. hillii have not previously been recorded from the
same locality. G. atrstralierrsis occurs in wet sclerophyll, for example in the
Brindabellas and beside Notitofagus at Lamington. G. killii has been found at
greater altitudes and in drier conditions than most Geonemertes. Stock (pers.
comm.) had often searched for Geonemertes in the wetter Nothofagus region
on the lower slopes of Point Lookout, but found none. G. hillii only occurs at
higher altitudes, under fallen timber in the drier areas where there are severe
frosts in winter (there were snow patches in July 1972 when we found 7
specimens). That both species have now been found on the Lamington plateau
in Queensland suggests however that they d o not require very different
habitats.
Tile distinctiort between G . australiensis and G. hillii
Colour remains the best character for distinguishing these two species. While
G. atistraliensis has many varieties it is never bright red like G. hillii. Internal
characters support this distinction. The eye number and the transverse cephalic
furrow must be abandoned as distinguishing features, and the presence
or absence of anterior caecal diverticula is a variable character in C. hillii
(though they have never been found immediately behind the brain as they are
in G. australiensis). The number of cephalic nephridia is difficult to assess and
dependent on the amount of cephalic gland. This leaves the amount and type
of cephalic gland and the relative size of the accessory lateral nerve as
apparently reliable distinguishing characters. When specimens of each species
are available, the distinction is easily made and the verdict in every instance
supports the diagnosis from colour. These internal characters are however
difficult to quantify or to define precisely for use on an isolated specimen.
The distinctive characters of C . stocki sp. nov.
G. sfocki belongs to the Australian group of species in that it shares all their
common characters. I t can be distinguished by unique characters of colour
pattern, fragmentation and posterior muscle development, and in the vascular
system. The cephalic gland resembles that of G. hillii while the size of the
accessory lateral nerve and of the anterior caecal diverticula resembles G.
australiensis. Despite the small size of C. sfocki, it resembles these two species
more closely than it resembles G. dendyi.
ACKNOWLEDGEMEmS
I am very grateful to Dr J. E. Smith for the opportunity to use the late
Professor C. F. A. Pantin's collection of Geonemertes and for introductions in
LAND NEMERTINES O F AUSTRALIA
43
Australia; to Professor T. Weis-Fogh for facilities in the Cambridge Zoology
Department; to the Royal Society and the Science Research Council for Travel
Grants; to Dr Ray Gibson for much helpful discussion; to Mr. D. J. Buck for
help in preparing slides and to Professor A. Stock for his kind hospitality and
help and for G. stocki.
I t is also a pleasure to thank the Australian Museum, in particular Dr P.
Hutchings, for lending material with permission for sectioning; Dr E. Riek for
his material; the Queensland Department of Forestry for permission to collect
material in Lamington National Park; Dr V. V. Hickman for material and
information; Professor A. Barnett for hospitality in the Zoology Department,
A.N.U.; Professor A. Horridge for facilities; Dr M. Tyrer, N. Coll, J. Mortlock
and R. Geppert for help in Canberra; Dr R. Kenchington in Townsville, Dr F.
H. Drummond in Melbourne: and many others for hospitality and help in
Australia. I should also like to thank my husband Dr N. W. Moore for much
help in finding Geonernertes and for reading the manuscript.
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