THE NATURAL |
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23 JUN 1998

PRESENTED
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VOLUME 64 NUMBER1 25 JUNE 1998

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© The Natural History Museum, 1998

Zoology Series
ISSN 0968-0470 Vol. 64, No. 1, pp. 1-109

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Bull. nat. Hist. Mus. Lond. (Zool.) 64(1): 1-62 Issued 25 June 1998

THE NATURAL
HISTORY MUSEUM

29 JUN 1998
PRESENTED

A revision of the cladoceran genus
Simocephalus (Crustacea, Daphniidae)

MARINA J. ORLOVA-BIENKOWSKAJA fe
A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prosp. 33, Moscow
117071 Russia

CONTENTS

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SYNOPSIS. Simocephalus, a world-wide genus of littoral freshwater Daphniidae is reviewed in full for the first time. Four
subgenera are recognized, one subgenus and two species are newly described. Eight species and subspecies are synonymized, a
number of previously synonymized species are reinstated and two species are transferred to the genus Daphnia. Thus, twenty
species are considered as valid members of the genus Simocephalus: subgenus Simocephalus s. str.: S. vetulus, S. elizabethae, S.
gibbosus, S. vetuloides, S. mixtus and S. punctatus sp. noy.; subgenus S. (Coronocephalus): S. serrulatus, S. semiserratus and S.
mirabilis sp. nov.; subgenus S. (Aquipiculus): S. latirostris, S. lusaticus andS. heilongjiangensis; new subgenus S. (Echinocaudus):
S. exspinosus, S. congener, S. acutirostratus, S. obtusatus, S. daphnoides, S. rostratus, S. brehmi, S. victoriensis. For each species,
accounts are given of nomenclature, distribution and morphology (with original figures ).A key for identification of subgenera and
species is provided.

© The Natural History Museum, 1998

INTRODUCTION

Freshwater Daphniidae of the genus Simocephalus Schédler, 1858
are common in littoral aquatic vegetation all over the world. These
‘tailless water fleas’ have been known since the middle of the 18th
century (Schaeffer, 1755), but their taxonomy remains unsettled,
with 61 specific and subspecific names proposed. Morphological
variability is poorly known. This makes the taxonomic status of
certain forms doubtful, since they may not represent taxa, but
merely morphological varieties. The descriptions of numerous spe-
cies are inadequate. Furthermore, some species which are supposed

M.J. ORLOVA-BIENKOWSKAJA

to be cosmopolitan, pantropical efc. are in fact groups of closely
related species, with restricted distributions. Obviously, a world-
wide revision of Simocephalus is necessary. Such an attempt is
made here.

The genus Simocephalus has been divided into four species
groups: S. (vetulus), S. (exspinosus), S. (serrulatus) and S. (latirostris)
(Orlova-Bienkowskaja, 1993a). The diagnostic characters of the
groups are stable and well-expressed in all representatives. Interme-
diate forms are absent. Furthermore, different characters are
congruent, that is, they combine species into the same groups. Thus
the species groups are given the rank of subgenera.

Fig. 1 Morphology of Simocephalus. a—abdomen, ab — anal bay, ae —aesthetes, at — anal teeth, al — antennule, a2 — base of antenna (antenna is not
shown), d—denticles of inner surface of ventro-posterior valve angle, dap — distal abdominal process, dd —denticles of ‘orsal valve margin, dh —
depression of head shield between head and valves, dpva — dorso-posterior valve angle, dv — point of divergence of valves, dvm — dorsal valve margin, e —
eye, f —fornices, fr —frons, g — gut, h—heart, hp — the place of head pores, 0 —ocellus, p—postabdomen, pap — proximal abdominal process, pe —
postabdominal claw, pe — parthenogenetic eggs, ps — plumose setae of inner surface of ventral valve margin, pym — posterior valve margin, r—rostrum, s —
setules of inner surface of posterior valve margin, sa — supra-anal angle, sp — sensory papilla of antennule, ss — sensory setae, vhm — ventral head margin,
vvm — ventral valve margin, 1st — 1st trunk limb, 2nd — 2nd trunk limb, 3rd — 3rd trunk limb, 4th — 4th trunk limb, Sth — 5th trunk limb.

REVISION OF SIMOCEPHALUS DAPHNIIDAE
MATERIALS AND METHODS

About ten thousand specimens from more than three hundred locali-
ties all over the world have been studied. Females of all species
except S§. /usaticus, males of nine species, and museum types of
fifteen taxa have been examined. Material examined is in the follow-
ing collections and institutions: AC — author’s collection deposited
in Zoological Museum of Moscow State University, AM — Austral-
ian Museum, Sydney, Australia, BMNH — The Natural History
Museum, London, Great Britain, MCA — Museum of Central Africa,
Tervuren, Belgium, MNO — Museum of Nature, Olten, Switzerland,
MV — Museum of Victoria, Australia, SAM — South Australian
Museum, Adelaide, Australia, ZI — Zoological Institute of the Rus-
sian Academy of Sciences, St.-Petersburg, Russia, ZICC — Cladocera
collection of ZI, ZICW — G.Ju. Werestchagin’s collection in ZI,
ZIPD — plankton depository of ZI, ZMC — Zoological Museum of
Copenhagen, Denmark, ZMO — Zoological Museum of Oslo Uni-
versity, Norway, ZMU — Zoological Museum of Uppsala University,
Sweden.

Original figures are made with the aid of a camera lucida. Keys
and diagnoses are based on adult specimens. The following addi-
tional abbreviations are used: CBS — canadian balsam slide, MPA —
material preserved in alcohol, PSEM — preparation for scanning
electron microscopy, PVAS — polyvinyl alcohol slide, 9 ad. — adult
parthenogenetic female, 9 juv.—juvenile parthenogenetic female, ° e.
— ephippial female. Morphological terms used below are shown on
Fig. 1.

In some cases I use a cluster analysis and diagrams of characters
for differentiation between closely related species. Four metric
characters are used (Fig. 2): W/L — ratio between width of dorso-
posterior valve prominence and body length, M/L — ratio between
length of dorso-posterior valve prominence and body length, G/L —
ratio between height of dorsal valve margin and body length, D/L —
ratio between diameter of dorso-posterior valve prominence and
body length. Body length (L) was measured with an ocular microm-
eter. Other measurements were made by drawing the body outline of
each specimen with the aid of the camera lucida and measuring the
details with an ordinary rule.

Statistical analysis employed the computer system ‘Statgraphics’.
Two-dimensional diagrams of characters are used for the detection
of morphological hiatus between closely related species. Each
specimen of each series is represented as a point on a coordinate
plane. Coordinates of the point are equal to measurements of the
specimen. Each series or group of series is represented with the
polygon including the points corresponding to all specimens. If the
polygons of two series/ groups of series do not overlap, there is a

Fig. 2 Measurements of valves. G — height of dorsal valve margin, W —
width of dorso-posterior valve angle, D — diameter of dorso-posterior
valve angle, M — length of dorso-posterior valve angle.

3

morphological hiatus between them. I also use four-dimensional
cluster analysis (average method) to determine which series are
close to each other. Diagrams of characters and cluster analysis are
independent of each other, because the former operates only with
extreme values, the latter only with average values of characters.
Therefore, if both methods give the same result, it is reliable.

MORPHOLOGY
Female

Valves

Maximum height of valves posterior to the middle. (Figs 1; 3B,C).
Posterior margin (Fig. l:pvym) oblique, almost straight. Point of
divergence of valves (Fig. I:dv) dorsal to dorso-posterior angle
(Fig. |:dpva). Dorsal, posterior and ventral margins with denticles
or smooth. Denticles arranged in 2 rows on dorsal margin (Fig.
I:dd). Inner valve surface with a row of plumose setae on ventral
margin (Fig. 1:ps), a row of setules groups on posterior margin (Fig.
l:s) and 2-5 plumose denticles near ventro-posterior angle (Fig.
I:d). Parthenogenetic female with 1-30 eggs in brood pouch.
Ephippium containing | egg (Fig. 3C).

Reticulation

Valves and head reticulated. Reticulation consists of oblique stripes
somewhat intersecting in mostof carapace and head and of polygons
along valve margin and in front of eye.

Head

Comparatively small, noticeably delimited by depression on dorsal
side (Fig. 1:dh). Rostrum always pointed, long or moderate. Frons
(Fig. 1:fr) rounded, pointed or right-angled, with denticles or devoid
of them. Ventral head margin (Fig. 1:vhm) with depression, deep or
shallow, near rostrum. Fornices very broad (Figs 4; 5; 1:f). Posterior
part of head with 3 main connected head pores, transversally orien-
tated (Fig. 5, HP) and 2 minute lateral head pores seen only with
scanning electron microscope, or without head pores. Eye and
ocellus always present.

Appendages

Antennule tubular (Figs 6C), having 9 aesthetes at end and | sensory
papilla proximally. Mandibles, maxillule and labrum as shown in
Figs 4, 6. Antenna (Fig. 7) comparatively short, ends of distal
segments reach only middle of valves. Proximal part of basipod with
2 setae (Fig. 7E), outer side of distal part with a seta (Fig. 7D), inner
side of distal part with a spine (Fig. 7C). Contrary to the opinion of
Manujlova (1964), the length of the distal seta does not differ in
different species. Exopod of antenna of 4; endopod of 3 cylindrical
segments. Second segment of exopod with a short spine, third with
a seta, fourth with 3 setae, of which one shorter than others and
curved (Fig. 7B). First and second endopod segment each with 1
seta, third segment with 3 setae. Contrary to the opinion of Behning
(1912) and Manujlova (1964) number of setae on each trunk limb
does not differ in different species. Interspecific differences concern
only the length of certain setae. The structure of trunk limbs (Figs 6;
8-11) has been described in detail (Orlova-Bienkowskaja, 1993b).

Postabdomen (Figs |:p; 12A,B)

High, with anal bay (Fig. 1:ab), supra-anal angle (Fig. 1:sa) and 2
rows of anal teeth (Fig. |:at). Distal anal teeth large, covered with
setules. Proximal teeth small, smooth. Dorsal part with groups of

M.J. ORLOVA-BIENKOWSKAJA

Fig. 3

setules. Postabdominal claws long (Fig. 1:pc), slightly curved, with
2 rows of setules and/or spines on concave side. Anus (Fig. |:ab) in
anal bay.

Abdomen with 2 processes (Fig. 1:pap,dap).

Male

Dorsal valve margin straight (Fig. 3A), ventral margin with an
embayment anteriorly. Head pores larger, antennules shorter and

S. vetulus. A, male, B, parthenogenetic female attached to a surface, C,

ephippial female.

more distended than in female (Fig. 6B), with 2 sensory papillae
proximally. First and second trunk limbs (Figs 8B,C; 13) differ
from corresponding limbs of female in several details (Orlova-
Bienkowskaja, 1993b) (Figs 8A and C). Postabdomen narrower
than in female (Fig. 14A). Vas deferens opening on supra-
anal angle (Fig. 14B,C) or distally. Fewer anal teeth than in fe-
male.
Abdominal processes absent.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 4 S$. vetulus head and mouth parts.

VARIABILITY

Age variability is similar in all species (Fig. 15). New-born fe-
males do not differ much from males: The brood pouch is small
and the dorsal valve margin almost straight. The prominence on
the dorso-posterior valve angle, if it present, is not distinct. Cara-
pace denticles are small and cover less of the valves than in
adults. Older females have a more distinct and sharp dorso-poste-
rior valve prominence. The shape of the brood pouch in the adult
depends on the number of eggs. The head grows slower than the
carapace. Valve shape in new-born males differs from that of
adults only in the absence of an embayment in the proximal part
of the ventral margin. The number of anal teeth correlates with
size in females. The ocellus in juveniles is shorter than in adults.
The postabdomen of neonates of both sexes lacks an anal bay,
supra-anal angle (Figs 12C; 15C), abdominal processes. The
fourth endite prominence of the first limb has a large hook bear-
ing a denticle at its end in the adult male (Fig. 8B) and small hook
lacking a denticle in the juvenile (Fig. 8D). The curved setae of
the second, third and fourth endite prominences of the second
limb are short in juvenile males and longer than the base of the
plumose seta of the first prominence in adults (Fig. 13B—D). The
morphology of third, fourth and fifth trunk limbs in males and all
trunk limbs in females does not depend on age.

Eye and ocellus size are subject to seasonal variation. This was
discovered in the following way: two series of S. vetulus were
collected in the same water-body in the Moscow region on 12. 5.
1990 and 5. 11. 1990. All specimens from the first sample had a

small eye and ocellus (Fig. 16A) and all those from the second
(parthenogenetic and ephippial females and males) a large one (Fig.
16B). Individuals from the sample of 5. 11. 1990 were kept at room
temperature. By the 17th day the size of the eye and ocellus in all
cases had become small (Fig. 16C).A similar result was obtained for
S. serrulatus.

Ocellus size is also affected by illumination intensity. It decreases
in darkness (Jermakov, 1924) and if the ventral part of the head is
covered by epibionts (personal observation) (Fig. 16D). Ocellus
shape varies within populations. In females of Simocephalus s. str. it
is straight or curved, widened in the middle or bifurcated at the end.
In males of these species and in both sexes in species of other
subgenera it is round or rhomb-like. The frons in S. (Coronocephalus)
bears a variable number of denticles. Individuals with and without a
prominence at the ventral head margin occur in all species except S.
gibbosus, S. elizabethae and S. obtusatus. A dorsal embayment
between carapace and head is more or less developed in all species.
Sometimes, there is a small prominence on the head near this
embayment (Fig. 16F).

There are pigmented spots in the valve tissue. Their shape and
colour differ within populations. The colour is green, brown or
orange and as a rule correlates with the colour of the gut contents.
According to Green (1966) carotenoid pigmentation depends on the
food composition.

The number of denticles at the ventro-posterior angle of the
valves varies from two to six. No correlation between number of
denticles and size was observed. There is some variability in shape
of the postabdomen and abdominal processes (Fig. 17).

6

SYSTEMATIC ACCOUNTS

Subgenus Simocephalus s. str.

TYPE SPECIES. Simocephalus vetulus (O.F. Miller, 1776)

DIAGNOSIS. Both sexes. Frons rounded, without denticles (Fig. 18).
Head shield without depression. Head pores present (Fig. 5). Inser-
tion of antennules at base of rostrum. Antennule short in
correspondence with short rostrum, with neitherridges nor denticles
on inner side (Fig. 6B,C). Aesthetes longer than base of antennule.
Postabdominal claws without spines (Fig. 12D,E). Inner and outer
side of claw with fine setules. Anal bay of postabdomen narrow,
rounded, with anal teeth (Fig. 12A).

Fig.5 S$. vetulus. Head shield. HP — head pores.

M.J. ORLOVA-BIENKOWSKAJA

Female. Dorso-posterior valve angle rounded or with rounded
prominence. Valves without dorsal keel. Posterior corner of
ephippium without protuberance (Fig. 3C). Ocellus elongate (ex-
ception: S. punctatus). Setae of 2nd and 3rd endite prominence of
2nd trunk limb as long as 0.3 and 0.2 of basal segment of plumose
seta of lst prominence respectively (Fig. 9B). Postabdomen with
10-15 anal teeth on each side. Supra-anal angle rounded (Fig. 12A).
Male. Supra-anal angle pointed (Fig. 14). Vas deferens opening
there. Postabdomen with 5-8 anal teeth on each side. Dorso-poste-
rior valve angle rounded or with small rounded prominence (Fig.
3A). Males of the following species have been examined: S. vetulus,
S. mixtus, S. vetuloides, S. punctatus, S. elizabethae. They do not
differ from each other, so only females are described.

REMARKS. Fig. 19A gives the cluster analysis of sixteen series
(each consisting of twenty specimens) from sixteen European

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 6 S. vetulus. A, maxillule, B, antennule of male, C, antennule of female, D, mandibles, E, molar region of mandibles.

populations of Simocephalus s. str. The dendrogram consists of 2
large clusters. The first of them combines the populations 1—13 (thin
line), and the second combines 14—16 (thick line). This means that
the similarity within both clusters is stronger than between them. In
other words, we can presume that populations 1-13 and 14-16
belong to two separate species. The diagrams of characters provide
support for this presumption (Fig. 19B,C). The areas occupied by
populations |—13 (thin line) and by populations 14—16 (thick line)
on the diagram only overlap to a minor extent at one point. There-
fore, there is a morphological hiatus between these groups.
Examination ofthe types shows that one of these species is S. vetulus
(1-13); the other is S. mixtus (14-16).

Similar reasoning shows that 2 species of Simocephalus s. str.: S.
mixtus and S. vetuloides occur in Eastern Siberia (Fig. 20). There
appear to be 3 species in Eurasia: S. vetulus in Europe, S. vetuloides
in Eastern Siberia and S. mixtus in all regions of Asia and in Eastern
Europe. The latter species is rather variable.

All measured African specimens (9 series) belong to S. mixtus. I

have also one series of S. vetulus from Morocco, but these specimens
are in poor condition and it is impossible to measure them.

S. vetulus (O.F. Miiller, 1776)

Figs 3-18

Daphne vetula O.F. Miiller, 1776: 199; Daphnia sima O.F. Miiller,
1785: 91: Monoculus nasutus Jurine, 1820: 133; Monoculus sima:
Jurine, 1820: 129; Simocephalus vetulus: Schédler, 1858: 18; S.
vetulus var. angustifrons Lilljeborg, 1900: 171;S. vetulus var. brandti
Cosmovici, 1900: 156 syn. nov. (nec Daphnia brandtii Fischer,
1848); S. vetulus angustifrons: Behning, 1941: 181; S. vetulus
gebhardti Ponyi, 1955: 313; S. mixtus hungaricus Ponyi, 1956: 57.

TYPE MATERIAL. The types appear to be lost. S. vetulus is often
confused with closely related species, so the designation of a
neotype is necessary. Neotype (designated here): Denmark, Zea-
land, vicinity of Copenhagen. Dyrehaven, 55°46'N, 12°34'E, 11. 5.
1901: MPA: 9 ad. (ZMC, CRU-319).

M.J. ORLOVA-BIENKOWSKAJA

Fig. 7 S. vetulus, antenna. A, general view, B, curved seta of exopod distal segment, C, inner side of basipod, distal part, D, outer side of basipod, distal

part, E, basipod proximal part.

MATERIAL EXAMINED. Neotype. Type material of junior synonyms:
S. vetulus angustifrons Lilljeborg, 1900: Lectotype (designated
here): Sweden, Uppsala, 9. 10. 1882, leg. Lilljeborg: MPA: 92 ad.
(ZMU, 399). Paralectotypes collected with lectotype: MPA:
13 9 Qad., 339 Qjuv., 72 Qe., SSA (ZMU, 399). Other speci-
mens: More than 2000 specimens (? Qad.,2 9 juv., 2 Qe.,c0°o’)
from 30 localities (Fig. 21) in Denmark, Greenland, Poland, Bul-
garia, European Russia, Ukraine, Georgia, Morocco, deposited in
AC, ZMC, ZICW. Some specimens are selected from the samples
from ZIPD.

DIAGNOSIS. Measurements. 2 9 ad.: 1.3—2.9mm.,@ Qe.: 1,2-
1,9mm,c' oO’: 1,1—-1,3mm.

Female. Dorso-posterior valve prominence short, with narrow base
and large diameter (Fig. 18). Its diameter greatly exceeds its length
(Fig. 2). Dorsal valve margin low, not protruding backward. Depres-
sions above and below dorso-posterior prominence small and shallow.
Ventral head margin straight or slightly concave, sometimes with
small prominence. Deep depression on ventral head margin near
rostrum. Ocellus elongate.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig.8 S. verulus. A, 1st limb of female, B, hook of endopod of Ist limb of adult male, C, Ist limb of male, D, hook of endopod of Ist limb of juvenile male.

DISTRIBUTION. (Fig. 21) Europe, North Africa. This species was
previously assumed to be cosmopolitan (Manujlova, 1964). But the
investigation of specimens from different regions shows, that S.
vetulus occurs in Europe and North Africa only. In other regions it is
replaced by closely related species: S. mixtus, S. vetuloides, S.
gibbosus, S. elizabethae and S. punctatus.

REMARKS. The original description of S. vetulus is very short:
“Daphne Vetula cauda inflexa, testa mutica’ (Miiller, 1776). This is
appropriate for any species of Simocephalus. Later, Miiller (1785)

renamed this species Daphnia sima. The name ‘vetulus’ is not
grammatically correct (Dumont, 1977). ‘Vetula’ means ‘an old
women. This is not an adjective, but a substantive. Its gender cannot
alter. However, it is not necessary to change the name ‘S. vetulus’,
because it has come into common use.

Some authors in the 19th century (Lievin, 1848; Baird, 1850;
Leydig, 1860) supposed S. exspinosus and S. congener to be syno-
nyms of S. vetulus. According to recent data, S. vetulus differs very
much from these species and even belongs to another subgenus.

According to Jurine (1820), S. nasutus (Monoculus nasutus

10 M.J. ORLOVA-BIENKOWSKAJA

SSS Set FF
—= =
= SET

KE SN LEE ye

KK

o,

an
Ces

Yi,
KKK
Ke

SS

SMMMAAQ0y5s

xe

Fig. 9 S. vetulus, female 2nd trunk limb. A, general view, B, endopod.

differs from S$. vetulus (Monoculus sima) in rostrum shape. How- S. vetulus var. angustifrons Lilljeborg differs from the typical
ever, judging from the illustrations in the original description, these form in the presence of a prominence on the ventral head margin.
species are identical. Information about the types of S. nasutus is Some authors (Behning, 1941; Manujlova, 1964) consider this
lacking. I agree with Lilljeborg (1900), that S. nasutus is a junior variety to be a subspecies, but I believe it to be a synonym, because
synonym of S. vetulus. I have found specimens both with and without the prominence in the
S. vetulus var. brandti Cosmovici was described from Romania. type material of S. vetulus var. angustifrons (Fig. 22). Moreover the
There is no information about the type material. Cosmovici (1900) animals with such a prominence sometimes occur in the most of
writes that he named this variety thus because it is intermediate Simocephalus species.
between S. vetulus and S. brandtii Fischer (= S. serrulatus). Refer- S. vetulus gebhardti and S. mixtus hungaricus were described

ring to the illustrations by Cosmovici, it is the junior synonym of S. from Hungary. The author (Ponyi, 1955, 1956) writes that these
vetulus. subspecies differ from S. vetulus vetulus in head shape and denticles

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Yyfy yy,

= \\ GU
~ aa \ QQQAG|S**® ii SS=SN

AL
Of UA \
AAI
AA yh
ALY
A ike
AS
“dL
4 ¥ \\"
AIRS
ALS
i f!
JAIN
7) iN Z
/ iN J
7 7
/ Z
Y

oF

FE

Fig. 10 S. vetulus, female 3rd trunk limb. A, general view, B, endopod.

on the dorsal margin of valves. However, judging from illustrations,
S. vetulus gebhardti and S. mixtus hungaricus are identical to S.
vetulus vetulus. The type material was destroyed during the battle in
Budapest in 1956 (Ponyi, personal communication). I agree with
Negrea (1983), that both names are the junior synonyms of S.

vetulus.

S. mixtus Sars, 1903

Fig. 23

Simocephalus mixtus Sars, 1903: 174; S. corniger Methuen, 1910:
158 syn. nov.; S. elizabethae: Manujlova, 1964: 148, partim; S.
vetulus: Fléssner, 1986: 179, partim. S. beianensis Shi, Shi, 1994:

405 syn. nov.

=
ee
xe 6
LE Spleens
Storeng a

POO oe
Se a: MI.
Se I rrit

Hi
HH
H} {{7
Bd) THY IAL tp
Mal Il Py
Ky} ty
MM! 14) Hd
Mi I) (Is
Al I a 4
Al Wa) ia Il
Zl \hd\ |) BAL IK
ZA\ WAT \W HAY IK
Y t'
“Y, LY } Ht |
Y\ Vl Vf a
Z| Aa
4 : b bX”)
2\ \A\ KA\ eA
/ \\

=<;

TYPE MATERIAL. Lectotype (designated here): Mongolia, Eastern
slope of Khingan mountain, 8. 11. 1911: MPA: Qad. (BMNH,

1995.742). Paralectotypes collected with lectotype: MPA: 142 Q ad.,
162 Qjuv. (BMNH, 1995.743-752).

MATERIAL EXAMINED. Lectotype, paralectotypes and other speci-
mens: more than 2500 specimens (2 Qad.,9 Qjuv.,? 9e.,c°o)
from 58 localities (Fig. 21) in Russia, Azerbaijan, Uzbekistan,
Tadjikistan, Kirgizia, Kazakhstan, Mongolia, China, Sri-Lanka,
India, Pakistan, Bangladesh, Vietnam, Azores, Algeria, Sudan, Egypt,
Ethiopia, USA, Jamaica. Material is deposited in AC, ZICW. Some
specimens are selected from the samples in ZIPD.

DIAGNOSIS. Measurements. @ ad.: 1.0—2.9mm, 2 Qe.: 1,2—
1.9mm,c' Co: 1.0-1,3mm.

Ss
a
SS

——=
=
—S

}
S55

‘A
(it
fae

M.J. ORLOVA-BIENKOWSKAJA

A
2 CSSeZ
} ~N INNSsss <
\
WS B

Soy
Sey

<—<Soe
SS
zs
es
~~]
za

SS
mas

SSF

CSS QS
BREET
ERR

HES
Lp

> <7
LES
LESH
Six
HIS

ss

=<
<>

SS

S

FE

L

a

Fig. 11S. vetulus, female trunk limbs. A, 4th limb, B, endopod of 4th limb, C, 5th limb.

Female. Dorso-posterior valve prominence of moderate length, with
wide base and large diameter (Fig. 23). Its diameter (Fig. 2) exceeds
its length. Dorsal valve margin high, protruding backward. Depres-
sions above and below dorso-posterior prominence of moderate size
(deeper than in S. vetulus, but more shallow than in S. vetuloides, S.
gibbosus and S.elizabethae). Ventral head margin straight or slightly
concave, sometimes with small prominence. Depression on ventral
head margin near rostrum deep. Ocellus elongate.

DISTRIBUTION.
America.

(Fig. 21) Asia, Eastern Europe, N. Africa, N.

REMARKS. Behning (1941) supposes S. mixtus to be a separate

species. Manujlova (1964) believes it to be a synonym of S.
elizabethae. Negrea (1983) and Fléssner (1972) consider it to be a
synonym of S. vetulus. Investigation of the type has shown that S.
mixtus differs from both S. vetulus and S. elizabethae.

S. corniger Methuen was described from South Africa. There is
no information about the type material. The original description
(Methuen, 1910) 1s very brief. Judging fromillustrations, S. corniger
is a Junior synonym of S. mixtus.

S. beianensis Shi, Shi, 1994 was described from China
(Heilongjang Province, 48°16'N, 126°31'E)(Shi & Shi, 1994). The
authors write that this species differs from S$. vetulus in details of
ocellus and in number of the anal teeth. Both characters are variable.

Referring to the illustration, the ocellus of S. beianensis does not
sufficiently differ from the ocellus of S. vetulus and S. mixtus. The
number of anal teeth does not also differentiate these species.

S. mixtus hungaricus Ponyi, 1956 is not in fact S. mixtus. It is a
synonym of S$. vetulus (see above). S. serrulatus var. mixta
Grochmalicki (1915) belongs to another subgenus. It is a junior
homonym of S. mixtus.

S. vetuloides Sars, 1898
Fig. 24

Simocephalus vetuloides Sars, 1898: 328; S. elizabethae: Behning,
1941: 182 partim; Manujlova, 1964: 148; S. vetulus: Fryer, 1957:
225 partim; Negrea, 1983: 138 partim.

TYPE MATERIAL. Lectotype (designated here): Russia, North Sibe-
ria, Jana river, 30. 6. 1885, leg. Ignatov: MPA: @ ad. (ZICC, 4690).
Paralectotypes collected with lectotype: 38 9 Q ad. (ZICC, 4690).
The vicinity of Jana river: CBS: 9 ad. (ZICW). Dolgulach, 16-18. 6.
1885: 32 Gad. (ZICW).

MATERIALEXAMINED (Fig. 21). Lectotype, paralectotypes and other
specimens from AC: Russia, vicinity of Yakutsk, 7. 1990, leg.
Smirnov: 189 Qad., 99 Qjuv. Chita, sand-pit, 9. 9. 1991, leg.
Smirnov: more than 709 Qad., 702 Qjuv., 1000h’'o’, 409 Qe.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 12S. vetulus, female postabdomen. A, lateral view, B, dorsal view, C, postabdomen of neonate, D, outer side of postabdominal claw, E, inner side of
postabdominal claw.

13

M.J. ORLOVA-BIENKOWSKAJA

Fig. 13 S. vetulus, male 2nd trunk limb. A, general view, B, endite of neonate, C, endite of juvenile, D, endite of adult.

Kolyma river basin, Zhirkovo lake, 28. 6. 1967, leg. Streletskaja:
49 Qad.,2 9 Qe. Magadan region, Verkhnee lake, 18. 8. 1981, leg.
Streletskaja: 13 9 Qad., 82 9 juv.

DIAGNOSIS. Measurements. 9 9 ad.: 1.3-2.4 mm.,@ Qe.: 1,2-
1,9 mm, oo: 1.0-1.3 mm.

Female. Dorso-posterior valve prominence long, with very wide
base and small diameter (Fig. 24). Its diameter (Fig. 2) less than its
length. Dorsal valve margin very high, not protruding backward.
Depressions above and below dorso-posterior prominence wide and
deep. Ventral head margin straight or slightly concave, sometimes
with small prominence. Depression on ventral head margin near
rostrum deep. Ocellus elongate.

DISTRIBUTION. (Fig. 21) Eastern Siberia S. vetuloides has been
described from the Jana river basin. Sars (1903) reports it also from
Kazakhstan. However, the illustration in this article shows that the
specimens found in Kazakhstan belong to S. mixtus. S. vetuloides is
reported from China (Chiang & Du, 1979), Mongolia (Flossner,
1986) and South Africa (Sars, 1916). But the identification of
species within the subgenus Simocephalus s. str. is rather difficult.
And probably the name S. vetuloides was misused for other species.

REMARKS. Behning (1941) and Manujlova (1964) suppose S.
vetuloides to be a synonym of S. elizabethae. Other authors (Fryer,

1957; Negrea, 1983; Michael & Sharma, 1988) regard it as a
synonym of S. vetulus. Investigation of the type material and other
specimens shows that it is a separate species. It is sympatric with S.
mixtus and there are no intermediate forms between these species. S.
vetuloides differs from S. vetulus in the shape of the dorso-posterior
valve prominence and from S. elizabethae in the head shape.

Contrary to the opinion of Manujlova (1964), the length of the
distal seta of the antennal basipod does not differ in this species from
the others (Fig. 24B). The basipod bears a seta on the outer and a
spine on the inner side of the distal part.

S. punctatus sp. nov.
Fig. 25

TYPE MATERIAL. Holotype: Shallow eutrophic vernal pool in river
bottom below a dam on the Friant River, Tulare Co. California, 37°N
119°45'W, leg. Berner: MPA: 9 ad. (BMNH) 1997. 1698. Paratypes
collected with holotype: MPA: more than 502 Qad., 202 9 juv.,
202 Ge., 200° 0O(BMNH 1997. 1699-1708 and AC).

DIAGNOSIS. Measurements. 9 9 ad.: 1.5-2.23mm.,? Qe.: 1,2-
1,9mm,o'o°: 1,1-1,3mm.

Female. Dorso-posterior valve prominence absent, dorso-posterior
angle not separated above and below by depressions (Fig. 25).

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 14S. vetulus, male postabdomen. A, lateral view, B, distal part, C, supra-anal angle with vas deferens.

Diameter of circle inscribed in it large. Dorsal valve margin low, not
protruding backward. Ventral head margin straight or slightly con-
cave, sometimes with small prominence. Depression on ventral head
margin near rostrum deep. Ocellus point-like.

ETYMOLOGY. The name ‘punctatus’ refers to the point-like ocellus
that is typical of this species.

REMARKS. The shapes of the head and valves are similar in S.
punctatus and S. vetulus. The former species differs distinctly from
the latter, and from all other species of this subgenus, in the shape of
the ocellus, which is point-like in all available specimens of S.
punctatus.

S. gibbosus Sars, 1896
Fig. 26

Simocephalus gibbosus Sars, 1896: 15;S. vetulus gibbosus: Dumont,
1983: 102.

TYPE MATERIAL. Lectotype (designated here): Australia, Sydney,
Centennial park: CBS: 9 ad. (ZMO,F 9766, Mp. 170). Paralectotypes
collected with lectotype: 5 9 9 ad. (ZMO, F 9766, Mp. 170), MPA:
15 2 Qad. (ZMO, F 19261).

MATERIAL EXAMINED (Fig. 21). Lectotype, paralectotypes and
other specimens: more than 250 specimens (Q Q ad. and 9 9 juv.)

M.J. ORLOVA-BIENKOWSKAJA

Fig. 15 Age variation in shape. A, S. vetulus female, B, S. exspinosus female, C, S. vetulus male postabdomen.

from 11 localities in Australia: New South Wales, Victoria, Queens-
land, Northern Territory. The material is in AM and AC.

DIAGNOSIS. Measurements. 9 Qad.: 1.0—2.4mm.,2 Qe.: 1.2-1.9.
Female. Dorso-posterior valve prominence long, with very wide
base and small diameter (Fig. 26). Its diameter less than its length
(Fig. 2). Dorsal valve margin very heigh, protruding backward
strongly. Depressions above and below dorso-posterior prominence
wide and deep. Ventral head margin always with prominence, with-
out depression under eye. Depression on ventral head margin near
rostrum very shallow, sometimes absent. Ocellus elongate.

Male. unknown.

DISTRIBUTION. (Fig. 21) Australia.

REMARKS. The original description of this species (Sars, 1896) is
comprehensive and provided with good illustrations. Dumont(1983)
supposes S. gibbosus and S. elizabethae to be subspecies of S.
vetulus. Examination of S. gibbosus type material and specimens of
S. elizabethae shows that these species differ from S. vetulus in the
shape of the valves and head. In addition, they are sympatric and
consequently cannot be subspecies of one species.

S. elizabethae (King, 1853)
Fig. 27

Daphnia Elizabethae King, 1853a: 247; Simocephalus vetulus:
Schédler, 1877: 18 partim, Negrea, 1983: 138 partim; S. vetulus
elizabethae: Dumont, 1983: 98; S. dulvertonensis Smith, 1909: 81.

REVISION OF SIMOCEPHALUS DAPHNIIDAE 17

Fig. 16 S. vetulus, variation. A-C, variation of ocellus size, A, female collected 12. 5. 1990, B, female collected 5. 9. 1990, C, female from the same
sample after 17 days in room temperature, D, head covered with epibionts, E, head without prominence in dorso-posterior part, F, head with prominence
in dorso-posterior part.

Fig. 17S. vetulus, variation of abdomen and postabdomen, female. A, postabdomen, B, abdominal processes.

18

M.J. ORLOVA-BIENKOWSKAJA

Fig. 18 S. vetulus, neotype, parthenogenetic female. A, postabdominal claw, B, lateral view.

TYPE MATERIAL. ‘Types were probably not preserved by King. At
least, they are not to be found in AM, SAM and MV. The speci-
mens were from Sydney, New Town, Parramatta, the Cowpastures,
and from River Karuah, near Stroud, Port Stephens. Type locality
not indicated in the original description (King, 1853a).

MATERIAL EXAMINED. More than 550 specimens(@ @ ad., 2 Q juv.,
2 Pe., Oo’) from 15 localities in Tasmania, New Guinea and
Australia (New South Wales, South Australia, Western Australia,
Victoria, Northern Territory, Queensland) (Fig. 21) (AM, SAM,
MV).

DIAGNOSIS. Measurements. 9 Qad.: 1.2—3.4mm., 2 Qe.: 1.2-1.9,
Oo: 1.1-1.3 mm.

Female. Dorso-posterior valve prominence long, with very wide
base and small diameter (Fig. 27): diameter less than its length (Fig.
2). Dorsal valve margin very high, not protruding backward. De-
pressions above and below dorso-posterior prominence wide and
deep. Ventral head margin with depression just under eye. Depres-
sion on ventral head margin near rostrum shallow, sometimes absent.
Ocellus elongate.

DISTRIBUTION. (Fig. 21) Australia, Tasmania, New Guinea. The
species is reported from Ceylon (Daday, 1898), Sumatra, Java,

REVISION OF SIMOCEPHALUS DAPHNIIDAE

137 14 15 “16

Fig. 19 Statistical analysis of 16 series of Simocephalus s. str. from Europe. 1-13 — S. vetulus, 14-16 — S. mixtus. A, result of cluster analysis, B, C,
diagrams of characters.

20

M.J. ORLOVA-BIENKOWSKAJA

“Te

Fig. 20 Statistical analysis of ten series of Simocephalus s. str. from East Siberia and Far East. 1-7 — S. vetuloides, 8-10 — S. mixtus. A, result of cluster

analysis, B, C, diagrams of characters.

China (Stingelin, 1904), India (Biswas, 1971), Niger (Dumont &
Van De Velde, 1977a), Nepal (Dumont & Van De Velde, 1977b),
Central Asia (Manujlova, 1964). But judging from illustrations,
these authors had specimens not of S. elizabethae but of S. mixtus.

REMARKS. The original description (King, 1853a) contains the
characters of two species. The first adequate description of this
species was made by Sars (1888). Schddler (1877) and Negrea
(1983) suppose S. elizabethae to be a synonym of S. vetulus.
Dumont (1983) regards it as a subspecies of S. vetulus. I believe S.
elizabethae to be a separate species, because it differs from S.
vetulus in the shape of the ventral head margin and dorso-posterior
valve prominence. These differences are not less than the differences
between other species within this subgenus.

Judging from the original description (Smith, 1909), the Tasma-
nian species S. dulvertonensis belongs to Simocephalus s.str .
Information about the type material is lacking. Available specimens
from Tasmania differ slightly from Australian material in the shape
of the dorso-posterior valve prominence, but this difference is
insufficient to assign them to a separate species or subspecies. I
agree with Brehm (1953) and Dumont (1983), that S. dulvertonensis
is a synonym of S. elizabethae.

Subgenus S. (Echinocaudus) subgen. nov.

TYPE SPECIES. Simocephalus exspinosus (De Geer, 1778).

DIAGNOSIS. Both sexes (Figs 28; 29). Frons rounded or pointed,
without denticles. Head shield without depression. Head pores
present. Insertion of antennules at base of rostrum. Antennule long
or short in correspondence with long or short rostrum, with neither
ridges nor denticles on inner side. Aesthetes longer than base of
antennule. Postabdominal claw with basal pecten of spines at outer
side. Inner side and distal part of outer side with fine setules. Anal
bay of postabdomen narrow, rounded, with anal teeth.

Female. Dorso-posterior valve angle with rounded prominence or
without it. Valves without dorsal keel. Posterior commer of ephippium
without protuberance. Ocellus short. Setae of 2nd and 3rd endite
prominence of 2nd trunk limbas long as 0.7 and 1.1 of basal segment
of plumose seta of Ist prominence respectively (Fig. 30B).
Postabdomen with 9-22 anal teeth on each side (Fig. 28C). Supra-
anal angle rounded.

Male. Supra-anal angle rounded (Fig. 29). Vas deferens opening near
its base. Postabdomen with 5-6 anal teeth on each side. Dorso-
posterior valve angle with rounded or pointed prominence.

REVISION OF SJMOCEPHALUS DAPHNIIDAE

ETYMOLOGY. The name ‘Echinocaudus’ is derived from the words
‘echinus’ — ‘hedgehog’ and ‘cauda’ — ‘tail’ and refers to the pecten of
spines at the base of postabdominal claw that is typical of this
subgenus.

S. obtusatus (Thomson, 1878)
Fig. 31

Daphnia obtusata Thomson, 1878: 261; Simocephalus obtusatus:
Sars, 1894.

TYPE MATERIAL. No information. Type locality: New Zealand,
Dunedin.

MATERIAL EXAMINED.
Henry: 9 ad. (AM, 7182).

DIAGNOSIS. Measurements. 9 9 ad.: 2.0-2.5mm,c"o": 1.0—1.2mm.
Both sexes. Frons rounded (Fig. 31D). Ventral head margin very
convex. Rostrum short. Setules on inner side of posterior valve
margin slender. Dorso-posterior valve angle without prominence
(Fig. 31A,F). One supra-anal angle (Fig. 31E). Basal pecten of
postabdominal claw with 10-12 large well-spaced spines (Fig.
31C). Size of spines maximal in middle.

(Fig. 32) New Zealand.

New Zealand, Lake Takapuna, leg.

DISTRIBUTION.

REMARKS. The original description was provided with an illustra-
tion and shows that S. obtusatus differs markedly from all other

21

species in head shape (Thomson, 1878). The most detailed descrip-
tion of the female and the first description of the male was given by
Sars (1894).

S. daphnoides Herrick, 1883
Fig. 33

Simocephalus daphnoides Herrick, 1883: 503; S. Iheringi Richard,
1897: 279 syn. nov.; S. fonsecai Bergamin, 1939: 82 syn. nov.; S.
fonsecai var. sinucristatus Bergamin, 1939: 84 syn. nov.

TYPE MATERIAL. Probably the types were not indicated by Herrick
as in the case of other species described by this author (D. Frey,
personal communication through N.N. Smirnov). Type locality:
U.S.A., Alabama, Decatur.

MATERIAL EXAMINED. Argentina, Rio Parana, Catay pond, 1973,
leg. Frutos: 39 Qad., 39 Qjuv. (AC). Peru, vicinity of Pucalpa,
pond near Ucayali river, 2. 1987, leg. Pegasov: 42 Q ad. (AC).

DIAGNOSIS. Measurements. 2 9 ad.: about 1 mm.

Female. Frons rounded (Fig. 33). Ventral head margin concave,
straight or with small prominence. Rostrum short. Setules on inner
side of posterior valve margin slender. Dorso-posterior valve angle
with large, pointed prominence. One supra-anal angle. Basal pecten
of postabdominal claw of 20-30 small, close-set spines of equal
length.

Male unknown.

Lee
NAS

\

>

@ S. vetulus Os. mixtus

© S. gibbosus @S. elizabethae

® S. punctatus

© S. vetuloides & S. mixtus

"

:

Os. vetulus & §S. mixtus
@s. elizabethae & S. gibbosus

MS. vetuloides

Fig. 21 Locations, where studied material of Simocephalus s. str. was collected.

DD,

M.J. ORLOVA-BIENKOWSKAJA

PP? 2PM

Fig. 22 S. vetulus var. angustifrons (=S. vetulus), type series. A, parthenogenetic female, lectotype, B, variability of ventral head margin.

DISTRIBUTION. (Fig. 32). U.S.A., Alabama (Herrick, 1883), Argen-
tina (Sars, 1901 and our data), Brasil (Richard, 1897), Paraguay,
Columbia (Olivier, 1960), Peru (our data).

REMARKS. The original description of this curious species is short
but provided with a good illustration (Herrick, 1883). Obviously, S.
daphnoides is the senior synonym of S. iheringi. The latter name is
used (Olivier, 1960) while the former name has been forgotten. S.
iheringi was described from Brasil (Richard, 1897). There is no
information about the types. The male was originally described by
Sars (1901).

S. fonsecai and S. fonsecai var. sinucristatus were described from
Brasil. There is no information about the types. Harding (1955)
supposes S. fonsecai to be a synonym of S. iheringi. The original
description (Bergamin, 1939) supplied with the lateral view of both

varieties and the view of the postabdomen of S. fonsecai shows that
both names are junior synonyms of S$. daphnoides.

S. (EXSPINOSUS) species group

DIAGNOSIS. Both sexes (Figs 28-30). Frons rounded. Ventral head
margin concave, straight or with small prominence. Rostrum short.
Setules on inner side of posterior valve margin slender. Dorso-
posterior valve angle without prominence or with small rounded
prominence. One supra-anal angle. Basal pecten of postabdominal
claw of 8—25 close-set spines of equal length.

S. exspinosus (De Geer, 1778)
Figs 28-30

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Monoculus exspinosus De Geer, 1778: 457; Daphnia exspinosa:
Koch, 1841: 35; Daphnia sima: Lievin, 1848; Baird, 1850: 95;
Simocephalus exspinosus Schédler, 1858: 20; Lilljeborg, 1900: 177;
Daphnia australiensis Dana, 1852: 1271; Sars, 1888: 15; S.
exspinosus australiensis: Dumont, 1983: 104; S. sibiricus Sars,
1898: 329 syn. nov. ; S. productus Sars, 1903: 173; S. himalayensis
Chiang & Chen, 1974: 129 syn. nov.; S. vamani Rane, 1985b: 225.

TYPE MATERIAL. The types appear to be lost. There are no speci-
mens of this species in the collection of De Geer deposited in the
Museum of Natural History in Stockholm (L. Sandberg, curator of
Crustacea, personal communication). The type locality is not indi-
cated in the original description (De Geer, 1778).

MATERIAL EXAMINED. Type material of junior synonyms: S. sibiricus
Sars, 1898: Lectotype (designated here): Russia, Siberia,
Verkhoyansk, 1885: MPA: 9 ad. (ZICC, 4691). Paralectotypes col-
lected with lectotype: 99 Qad. (ZICC, 4691). S. productus Sars,
1903: Lectotype (designated here): Kazakhstan, Akmolinsk region:
MPA: @ ad. (ZICC, 7098). Paralectotypes collected with lectotype:
35 2 Qad. (ZICC, N7098). Other specimens: more than 1000 speci-
mens (2 Qad., 9 Qjuv., 9 Qe,c'o’) from 56 localities in Russia,
Ukraine, Georgia, Kazakhstan, Uzbekistan, Tadjikistan, Mongolia,

23

China, India, Pakistan, Bangladesh, Egypt, Algeria, Rwanda, South
Africa and Australia. Material is deposited in AC, ZICW, ZICC,
MCA, SAM, AM. Some specimens are selected from the samples
from ZIPD.

DIAGNOSIS. Measurements. 9 9 ad.: 1.8-3.5mm., 9 Qe.: 1.2
1.9mm,o'o": 1.0-1.3.

Female. (Fig. 28). 12-22 anal teeth. Prominence of dorso-posterior
valve angle small or absent. Basal pecten of postabdominal claw of
8—12 spines of moderate size.

DISTRIBUTION. This species is assumed to be cosmopolitan by
many authors, but its range needs to be redefined. It occurs with
certainty in Europe, Asia, Africa, Australia (Fig. 32). The available
specimens from different continents belong to one morphological
species. Unfortunately, I have no specimens from America.

REMARKS. The original description of S. exspinosus is very short:
‘Monoculus exspinosus branchiis dichotomis cauda simplici inflexa
testa postice rotundata non spinosa’ (De Geer, 1778). This is appro-
priate for any species of Simocephalus. Koch and Schdédler are often
erroneously thought to be the authors of the species, because Koch
(1841) described and drew it and Schédler (1858) was the first to

Fig. 23S. mixtus, type series A, parthenogenetic female, lectotype, B, ventral part of the head of paralectotype.

24

M.J. ORLOVA-BIENKOWSKAJA

I 7 | ae

Fig. 24S. vetuloides, lectotype, parthenogenetic female. A, general view, B, distal part of antenna basipod with a seta on outer side and a spine on inner

side.

assign it to the genus Simocephalus. But their descriptions are
insufficient. Some authors supposed S. exspinosus to be the junior
synonym of S. vetulus (Daphnia sima) (Lievin, 1848; Baird, 1850).
Lilljeborg (1900) was the first to describe this species appropriately.

S. australiensis was originally described insufficiently (Dana,
1852). Dana’s collection with the type was lost on a ship which sank
(D. Frey, personal communication through N.N. Smirnoy). Sars is
often supposed to be the author of this species (Negrea, 1983)
because he is the first to describe it appropriately (Sars, 1888). He
believed S. australiensis to be a separate species closely related with
S. exspinosus and differing from it by ‘the peculiar oblique form of
the carapace and well-marked, though obtuse, projection of its
posterior extremity; likewise too by the broad tail, and more espec-
ially by the highly characteristic armature of the caudal claws’.
Dumont (1983) regards S$. australiensis as a subspecies of S.
exspinosus. Other authors regard it as a synonym (Floéssner, 1972;
Negrea, 1983; Margaritora, 1985; Michael & Sharma, 1988). agree
with the latter opinion, because the diagnostic characters used by
Sars and Dana are rather variable and because all available speci-
mens of the S. (exspinosus) species group from Australia do not
differ from European S. exspinosus.

According to Sars (1898, 1903), S. sibiricus and S. productus
differ from each other and from S. exspinosus in the head shape, the

size of the dorso-posterior valve prominence and the armature of the
postabdominal claw. Manujlova (1964) mentions S. sibiricus as a
separate, highly variable species. Judging from illustrations, she
confuses two species under this name. S. productus is believed to be
a synonym of S. exspinosus (Manujlova, 1964; Michael & Sharma,
1988). Investigation of the type has shown that S. productus and S.
sibiricus do not differ from S. exspinosus. The frons shape varies
from rounded to almost right-angled. The head height also varies
within populations. Therefore these features cannot be diagnostic
characters.

S. himalayensis is described from the Himalayas (Chiang & Du,
1979). The type is in China and I have not seen it. Reference to the
original description and illustrations suggests that S. himalayensis is
a synonym of S. exspinosus.

According to Rane (1985b), S. vamani, described from Jabalpur
(India) differs from S. exspinosus in its moderate size, a compara-
tively small rostrum, and the presence of 6-7 denticles on the
postabdomen near the insertion of the claw. This author also states
that S. austarliensis differs from S. vamani in the upturned rostrum.
According to my data, the group of 6—7 denticles near the claw
occurs in all Simocephalus species and the size and orientation of the
rostrum is subject to individual variability. The type is deposited in
the National collection of the Zoological Survey of India (Calcutta).

REVISION OF SIMOCEPHALUS DAPHNIIDAE

25

Fig. 25 S. punctatus sp. nov., holotype, parthenogenetic female.

Sharma & Sharma (1990) sink S. vamani into the synonymy of S.
exspinosus on the base of the investigation of the type. I agree with
them because all available specimens of the S. (exspinosus) group
from India belong to S. exspinosus.

S. congener (Koch, 1841)
Fig. 34

Daphnia congener Koch, 1841: 35; Simocephalus congener:
Schédler, 1858: 20; Sramek-HuSek et al., 1962: 265; S. exspinosus
var. congener: Lilljeborg, 1900: 177; S. exspinosus: Sars, 1888: 16;
Flossner, 1972: 184.

TYPE MATERIAL. ‘The types appear to be lost. Type locality not
indicated in the original description. Probably it is in Germany.

MATERIAL EXAMINED.

Russia, Moscow region, Ruza district,
Terekhovsky pond near Glubokoe lake, 29. 7. 1983, 29. 7. 1983, leg.
Korovchinsky., 19. 8. 1989, leg. Orlova-Bienkowskaja: more than
209 Qad., 209 Pjuv., 109 Ve. Vicinity of the Lake Baikal, Maloe
More, pool at the swamp, 19. 8. 1982, leg. Glagolev: 102 Qad.,
149 Qjuv. Vicinity of the Lake Baikal, Proval, water-meadow at
Oblom, 20. 8. 1982, leg. Glagolev: 2 2 Q ad. All series are in AC.

DIAGNOSIS. Measurements. 9 9 ad.: 1.5-2.2mm, 2 9 e.:1.2-1.8mm.
Female. (Fig. 34). 9-18 anal teeth. Prominence of dorso-posterior
valve angle absent. Basal pecten of postabdominal claw of 20-25
small spines.

DISTRIBUTION. (Fig. 32) This species was previously confused with
S. exspinosus, so its range needs to be redefined. It occurs with
certainty in Central and Eastern Europe and Siberia.

26

REMARKS. The original description of S. congener is insufficient
(Koch, 1841). Lilljeborg (1900) was the first to describe it appropri-
ately, though this author believes this species to be a variety of S.
exspinosus. Most authors suppose S. congener to be asynonym of S.
exspinosus (Sars, 1888; Fldéssner, 1972; Margaritora, 1985; Sharma
& Michael, 1988) or a variety (subspecies) (Behning, 1941). But
Sramek-Husek er al. (1962) regard it as a separate species. I believe
the latter opinion to be correct because there is a morphological
hiatus between S. exspinosus and S. congener in the number and size
of spines on the postabdominal claw. In addition, these species are
sympatric in Europe.

S. (ACUTIROSTRATUS) species group

Female (Fig. 35). Frons pointed. Ventral head margin concave.
Rostrum long. Setules on inner side of posterior valve margin thick.
Dorso-posterior valve angle without prominence or with rounded
prominence. Two supra-anal angles. Basal pecten of postabdominal
claw of 10-15 large, close-set spines, which increase in size distally.
Male. Unknown.

S. acutirostratus (King, 1853)
Fig. 35

Daphnia Elizabethae var. acuti-rostrata King, 1853b: 254;
Simocephalus acutirostratus: Sars, 1896: 12;S. paradoxus Schédler,
1877; S. vidyae Rane, 1983: 154; S. vidyae gajareae Rane, 1986:
168.

M.J. ORLOVA-BIENKOWSKAJA

TYPE MATERIAL. ‘Type probably not indicated by King. Type local-
ity: Australia, New South Wales, ponds in Denham Court.

MATERIALEXAMINED. (Fig. 32) Australia, New South Wales, swamp
26km east of Cobar, 31°30'S 146°7'E, 12. 12. 1973, leg. Timms:
more than 20 2 9 ad., 20 2 9 juv. New South Wales, Casino, 28°52'S
153°3'E, leg. Henry: 9 ad. New Caledonia, dam near La Foa, 21°50'S
166°53'E, 8. 8. 1981, leg. De Deckker: 2 juv. Queensland, pool at
the road side, 30. 6. 1974: 29 Qad., 52 Qjuv. Queensland, Lake
Lalilee, 22°19'S 145°51'E, 22. 4. 1984, leg. Timms: 9 ad. Material in
AM and AC.

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-3.0mm.

Female. General body shape ovoid (Fig. 35). Frons with large sharp
prominence. Dorso-posterior valve prominence distinct, separated
above and below with shallow, wide depressions. Diameter of circle
inscribed in it large. Dorsal margin with denticles. Proximal and
distal supra-anal angles large, embayments of postabdomen deep,
proximal angle rounded.

DISTRIBUTION. (Fig. 32) This species is reported fran Australia
(King, 1853b), Philippines (Mamaril & Fernando, 1978), India
(Michael & Sharma, 1988), Sri-Lanka (Rajapaksa, 1981), China
(Chiang & Du, 1979), Lake Tanganyika and Venezuela (Zoppi De
Roa & Vasquez, 1991), but the name S. acutirostratus has been so
often misused for other species that its range needs to be redefined.
It occurs with certainty in Australia and South-East Asia.

REMARKS. This species was originally described as a variety of S.
elizabethae. The types are obviously lost. The original description
and illustration (King, 1853b), allow identification of this remark-
able species with certainty. Sars (1896) gives S. acutirostartus the
rank of a species.

Fig. 26 S. gibbosus, lectotype, parthenogenetic female. A, lateral view, B, postabdomen.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

S

ee!

<<
SS

SS

2

Fig. 27S. elizabethae, parthenogenetic female. A, head, B, lateral view.

27

28

>

Fig. 28 S. exspinosus, parthenogenetic female. A, postabdominal claw, B, lateral view, C, postabdomen.

M.J. ORLOVA-BIENKOWSKAJA

29

————_

=5
AY Sn =

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 29S. exspinosus, male. A, lateral veiw, B, postabdomen, C, antennule.

WRI

Fig. 30S. exspinosus female, trunk limbs, A, Ist limb, B, endite of 2nd limb.

30

Schoédler (1877) renamed S. acutirostratus as S. paradoxus. Con-
sequently, the latter name is an objective junior synonym of the
former.

S. vidyae Rane and S. vidyae gajareae Rane were described from
Jabalpur (India). The descriptions (Rane, 1983, 1986) are very
detailed and provided with excellent illustrations, but do not contain
any characters which differentiate these taxa from S. acutirostratus.
The types are deposited in the National collection of the Zoological
Survey of India (Calcutta). Sharma & Sharma (1990) sink both
names into the synonymy of S. acutirostratus on the basis of
investigation of these types.

S. victoriensis Dumont, 1983

Fig. 36

Simocephalus acutirostratus: Haase, 1903: 150 (partim); S.
victoriensis Dumont, 1983: 105.

TYPE MATERIAL. Holotype: Australia, Victoria, temporary pool 7km
W of Edenkope, 37°2'S 141°17'E, 19. 10. 1978, leg. Morton:
PVAS: 9 ad. (AM, P31316).

MATERIAL EXAMINED. (Fig. 32) Holotype and other specimens:

M.J. ORLOVA-BIENKOWSKAJA

Australia, New South Wales, a lake near Cooma, 12. 5. 1975:
49 Qad., 122 Q juv. Lake Maffa, 13.5. 1975:39 Qad., 102 9 juv.
South Australia, Tatiara, 4km N of Bordertown, 6. 11. 1979, leg.
Zeidler: 5 Q Qad., 2 juv. A lake on Nimakel-Bumbala road, 14. 5.
1975: 89 Qad., 29 Qjuv. The material is in SAM and AC.

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-3.0mm.

Female (Fig. 36). General body shape rounded. Frons with small
rounde prominence separated above and below with depressions.
Dorso-posterior valve prominence absent. Diameter of circle in-
scribed in dorso-posterior valve angle very large. Dorsal margin
without denticles. Proximal and distal supra-anal angles small,
embayments of postabdomen shallow, proximal angle rounded.

DISTRIBUTION.
tralia, Victoria.

(Fig. 32) Australia: New South Wales, South Aus-

REMARKS. There is no doubt that S. victoriensis and S. acutirostratus
are separate species because they are sympatric and differ markedly
from each other.

Judging from illustration made by Haase (1903), the author
examined specimens of S. victoriensis but erroneously identified
them as S. acutirostratus.

Fig. 31 S. obtusatus (after Sars, 1894). A, parthenogenetic female, lateral view, B, parthenogenetic female, dorsal view, C, postabdominal claw, D, head,

E, postabdomen, F, male.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

31

Ne

O Ss. exspinosus
@s. acutirostratus
© S. victoriensis

@ S. rostratus

Fig. 32 Locations, where studied material of S. (Echinocaudus) was collected.

S. brehmi Gauthier, 1939 stat. nov.
Fig. 37

Simosa acutirostrata brehmi Gauthier, 1939: 144; Simocephalus
acutifrons Johnson, 1954: 954 syn. nov.

TYPE MATERIAL. Types (59 Qad.) were in Gauthier’s collection
before it was nationalized by the Algerian government. There is no
information about the place, where this collection is now (Hudec,
1993).

MATERIAL EXAMINED. (Fig. 32) Type material of junior synonym S.
acutifrons Johnson. Holotype: South Africa, Kempton Park, Johan-
nesburg: MPA: 9 ad. (BMNH). Paratype collected with holotype:
MPA: 9 ad.(BMNH). Other specimens: Tanzania, Mt Hanang:
23 2 Qad., 29 Yjuv. (MCA). Southern Rhodesia, Plumtree, 7. 2.
1954: 49 Qad., 9e., 29 Yjuv. (ZICC).

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-3.0mm.

Female (Fig. 37). General body shape ovoid. Frons with small
obtuse prominence not separated above and below by depressions.
Dorso-posterior valve prominence distinct, separated above and
below by deep, wide depressions. Diameter of circle inscribed in it
moderate. Dorsal margin with denticles. Proximal and distal supra-
anal angles large, embayments of postabdomen deep, proximal
angle sharp.

DISTRIBUTION. (Fig. 32) Vicinity of Lake Chad, Southern Rhode-

Q@ S. victoriensis & S. exspinosus

@© S. acutirostratus gS. exspinosus

@ S. exspinosus & S. congener

Os. brehmi
@ S. obtusatus
© S. daphnoides

@ undescribed species of S. (acutirostratus) group

sia, Tanzania, South Africa. This species is also reported from Brasil
by Brehm (Gauthier, 1939). Unfortunately, no specimen of this
species group from SouthAmerica is available and it is impossible to
confirm or to disprove this report.

REMARKS. _ S. brehmi differs from S. acutirostratus in the shape of
the valves and postabdomen. These forms are allopatric, so the
question of specific or subspecific rank of S. brehmi is difficult, but
I take S. brehmi to be a separate species because the differences
between it and S. acutirostratus are not less than those between other
species in this group.

S. acutifrons, described from Johannesburg (South Africa), is
identical to S. brehmi, judging by the examined type material.
Johnson (1954) does not point out any characters which distinguish
his species from S. brehmi and S. acutirostratus.

S. rostratus Herrick, 1884
Fig. 38
Simocephalus rostratus Herrick, 1884.

TYPE MATERIAL. ‘The type is probably lost, like those of other
species described by Herrick (D. Frey, personal communication
through N.N. Smirnov).

MATERIAL EXAMINED. (Fig. 32) Canada, Waterloo National Park,
15. 9. 1972, leg. Smirnov: 102 Qad., 102 Qjuv. (AC).

32 M.J. ORLOVA-BIENKOWSKAJA

Fig. 33S. daphnoides, parthenogenetic female. A, lateral view, B, endite of 2nd trunk limb, C, outer side of postabdominal claw, D, postabdomen, E,
inner side of postabdominal claw.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

38

Fig. 34S. congener, parthenogenetic female. A, postabdominal claw, B, lateral view.

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-3.0mm.

Female (Fig. 38). General body shape ovoid. Frons with small
obtuse prominence not separated above and below by depressions.
Dorso-posterior valve prominence distinct, separated above and
below by deep depressions. Dorsal margin with denticles. Diameter
of circle inscribed in it small. Proximal and distal supra-anal angles
small, embayments of postabdomen shallow, proximal angle rounded.

DISTRIBUTION. (Fig. 32) U.S.A., Canada.

REMARKS. ‘The original description of this species is not provided
with an illustration (Herrick, 1884). It is evident from the descrip-
tion that it is closely related with S. acutirostratus. ‘The spine is as

in S. americanus’ (S. serrulatus) and ’the head is produced below
the eyes in an angle, like a right angle, which is not spiny’. I had
serious doubt about the taxonomical state of this taxon (Orlova-
Bienkowskaja, 1993), because there were no other records of S.
(acutirostratus) species group from North America. The examina-
tion of specimens from Canada has shown that they belong to this
group and differ from S. acutirostratus, S. victoriensis and S.
brehmi in the shape of the dorso-posterior valve angle. Obviously,
they belong to S. rostratus.

There is one undescribed species of S. (acutirostratus) group in
North America. I have about forty specimens of this species from
California and Washington, but I do not name this new species

34 M.J. ORLOVA-BIENKOWSKAJA

Fig. 35 S. acutirostratus, parthenogenetic female. A, lateral view, B, outer side of postabdominal claw, C, inner side of postabdominal claw, D,
postabdomen and abdomen.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 36S. victoriensis, parthenogenetic female. A, head, B, lateral view, C, postabdomen.

36 M.J. ORLOVA-BIENKOWSKAJA

Fig. 37 S. brehmi, parthenogenetic female. Holotype of S. acutifrons = S. brehmi. A, lateral view, B, postabdominal claw.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 38S. rostratus, parthenogenetic female.

37

38 M.J. ORLOVA-BIENKOWSKAJA

Fig. 39S. serrulatus, parthenogenetic female. A, lateral view, B, outer side of postabdominal claw, C, inner side of postabdominal claw, D, setules of
posterior valve margin, E, distal part of postabdomen.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

ee

Coy
,
Xx

‘i

oy

59

Fig. 40S. serrulatus. A, ephippial female, B, postabdomen, male, C, male, D, outer side of male postabdominal claw.

because it was originally discovered by B. Hann (D. Berner, per-
sonal comunication) and she has already started working on its
description.

This species undoubtedly belongs to the S. (acutirostratus) spe-
cies group because its frons is pointed, without denticles, and its
postabdomen has two supra-anal angles. It differs from S.
acutirostratus, S. brehmi and S. rostratus in the absence of a dorso-
posterior valve prominence and from S. victoriensis in the shape of
the postabdomen and head.

Subgenus S. (Coronocephalus) Orlova-Bienkowskaja, 1995

TYPE SPECIES. Simocephalus serrulatus (Koch, 1841).

DIAGNOSIS. Both sexes (Figs 39-42). Frons right-angled, with
denticles (S. serrulatus, S. semiserratus) or without them (S.
mirabilis). Head shield without depression. Head pores absent.
Insertion of antennules at end of rostrum. Antennule short in corre-
spondence with short rostrum, with transversal ridges covered with
denticles on inner side. Aesthetes shorter than base of antennule.
Postabdominal claw with spines on proximal part of outer side and
on inner side. Basal part of outer side with fine setules. Anal bay of
postabdomen narrow, rounded, with anal teeth.

Female. Dorso-posterior valve angle with rounded prominence.
Valves without dorsal keel. Posterior corner of ephippium without
protuberance. Ocellus short (S. serrulatus and S. semiserratus), or
elongate (S. mirabilis). Setae of 2nd and 3rd endite prominence of

40

M.J. ORLOVA-BIENKOWSKAJA

cx \\
SOK

Fig. 41S. serrulatus, parthenogenetic female. A — C, E, interpopulational and age variability, A, type series of S. serrulatus var. montenegrinus
(Montenegro), B, series from the vicinity of Vladivostok, C, type series of S. capensis, E, series from Taimyr, D, head shield, dorsal, F — head, ventral, G,

head, lateral.

2nd trunk limb as long as 0.3 and 0.9 or 0.6 and 0.4 of basal segment
of plumose seta of 1st prominence respectively. Postabdomen with
9-15 anal teeth on each side. Supra-anal angle rounded.

Male. Supra-anal angle rounded. Vas deferens opening in middle of
anal bay. Postabdomen with 3-5 anal teeth on each side. Dorso-
posterior valve angle with small rounded prominence. There is no
morphological hiatus between males of S. serrulatus and S.
semiserratus. The male of S. mirabilis is unknown, so only the
females of these species are described.

ETYMOLOGY. The name ‘Coronocephalus’ is derived from the
words ‘corona’ — ‘crown’ and ‘cephalon’ — ‘head’ and refers to
spines on the head that are typical of this subgenus.

REMARKS. The subgenus consists of three species: S. serrulatus,
S. semiserratus and S. mirabilis sp.nov. The first is distributed
world-wide. Statistical analysis of its variation (Orlova-
Bienkowskaja, 1995a) has revealed that it has no geographical
races and that there is a morphological hiatus between S.
serrulatus and S. semiserratus in two pairs of independent metric
characters. In addition, these species differ from each other in the
number of denticles on the valve margin. S. serrulatus and S.
semiserratus are sympatric in South America. Therefore, they are
not subspecies but separate species. S. mirabilis differ from S.
serrulatus and S. semiserratus in having an elongate ocellus and
in the absence of denticles on the frons.

REVISION OF SIMOCEPHALUS DAPHNIIDAE
S. serrulatus (Koch, 1841)
Figs 39-42

Daphnia serrulata Koch, 1841: 35; D. brandtii Fischer, 1848: 177;
D. intermedia Lievin, 1848: 29; Simocephalus serrulatus: Schodler,
1858; Simocephalus americanus Birge, 1878; S. capensis Sars,
1895: 15; S. inflatus Vavra, 1900: 12; 8. serrulatus var. productifrons
Stingelin, 1904: 57; S. serrulatus var. montenegrinus Werestchagin,
1912: 7; S. serrulatus var. mixta Grochmalicki, 1915: 220 (nec S.
mixtus Sars, 1903); S. serrulatus var. rotundifrons Brehm, 1933: 54;
S. kerhervei Bergamin, 1939: 63; S. agua-brankai Bergamin, 1939:
64: S. serrulatus var. armata Brehm, 1956: 221; S. serrulatus var.
pelagicus Brehm, 1959; S. surekhae Rane, 1985a: 159.

TYPE MATERIAL. The types appear to be lost. No type locality is
indicated in the original description. Probably it is in Germany.

MATERIAL EXAMINED. (Fig. 43) Type material of junior synonyms:
S. serrulatus montenegrinus Werestchagin, 1912: Lectotype (desig-
nated by Orlova-Bienkowskaja (1995a)): Montenegro, Lake Scutari,
15. 6. 1911, leg. Werestchagin : MPA: 9 ad. (ZICC, 7085).
Paralectotypes collected with lectotype: MPA: 39 Qad., 2 juv
(ZICC, 7085, 7086), Montenegro, vicinity of Rijeka, leg.
Werestchagin: CBS: 22 Qad.,22 Qjuv. (ZICW). S. capensis Sars,
1895: Lectotype (designated by Orlova-Bienkowskaja (1995a)):

41

SouthAfrica, Knysna, hatched from dry epphipia: MPA: 9 ad. (ZMO,
F 18357). Paralectotypes collected with lectotype: MPA: 15 9 Q ad.,
102 Qjuv., 82 Qe. (ZMO, F 18357), 160°C (ZMO, F 183578).
Other specimens: about 1500 specimens (@ @ad., 9 Qjuv.,? Pe.
ando’o’) from Russia, Kazakhstan, China, India, Bangladesh, Viet-
Nam, Burkina Faso, Central Africa, Niger, Nigeria, Mauritania,
Sudan, Canada, U.S.A., Guatemala, Nicaragua, Argentina, Brasil,
Australia (ZICW, ZIPD, AM, AC). More percise geographical data
have been published previously (Orlova-Bienkowskaja, 1995a).

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-2.0mm,@ Qe. 1.0-
1.5mm, o": 0.7—1.0mm.

Female. Dorso-posterior valve prominence large, separated from the
rest of valves by deep embayment. Its length exceeds the diameter of
a circle inscribed in its contour. Denticles cover the ventral, posterior
and more than 1/3 of the dorsal margin. Ocellus short. Frons with
denticles. Setae of 2nd and 3rd endite prominence of 2nd trunk limb
as long as 0.3 and 0.9 of the basal segment of plumose seta of Ist
prominence respectively.

DISTRIBUTION. (Fig. 43) Europe, Asia, Africa, North America,
South America, Australia.

REMARKS. Fig. 41 shows the interpopulational variability of head
height, and size and shape of the dorso-posterior valve angle. A
number of subspecies and even separate species have been described

Tie

cp

Ly

ZOE

Ki Beste
“OOF "
“ppl
j

Ne RS
MW
VWi7/NZIS

Fig. 42S. serrulatus, female. A, antennule, lateral, B, antennule, dorsal, C, Ist trunk limb, D, endite of 2nd trunk limb.

42

mies

a

@ S. serrulatus

inae ww:
Fala

PU aL TT SEs
CWE TTR a7

O Ss. semiserratus

M.J. ORLOVA-BIENKOWSKAJA

\ 4

y,

© S. mirabilis

Fig. 43 Locations, where the studied material of S. (Coronocephalus) was collected.

because of these variations. However, I believe, that S. serrulatus has
no subspecies. First, there is no morphological hiatus between
populations. There are always some specimens with intermediate
characters (Orlova-Bienkowskaja, 1995a). Second, the variability is
not geographical and sometimes neighbouring populations differ
more strongly than populations from different continents.

This interpopulational variability is probably the consequence of
the founder-effect, which is strong in Cladocera because of parthe-
nogenesis. It conforms with the data of Hann & Hebert (1986), who
studied the genetic structure of North American Simocephalus
populations. Based on a study of enzymes, these authors came to the
conclusion that the genetic diversity within populations 1s less than
between populations. They supposed it to be a consequence of the
founder-effect.

The original description of S. serrulatus was supported by good
illustration and contains most of the characters which differentiate
this species from others (Koch, 1841).

S. brandtii and S. intermedius, described from Europe, are tradi-
tionally regarded as synonyms of S. serrulatus. The types are
probably lost, but the original descriptions (Fischer, 1848; Lievin,
1848) show that this opinion is correct. The name S. vetulus var.
brandtii Cosmovici, 1900 is the junior secondary homonym of S.
brandtii (Daphnia brandtii Fischer, 1848). Accorging to Article 59a
of the International Code of Zoological Nomenclature (1988), it is
invalid. It is not necessary to propose the replacement name (Art.
60a), because S. vetulus var. brandtii is the junior synonym of S.
vetulus. The name S. intermedius Studer is not the secondary
homonym of S. intermedius (Lievin) (Daphnia intermedia Lievin,

1848) (Art. 60c), because the species described by Studer (1878) is
assigned to the genus Simocephalus erroneously and belongs to the
genus Daphnia.

S. serrulatus var. montenegrinus Werestchagin, 1912 was described
from Montenegro (Fig. 41A). Itis regarded as a subspecies (Behning,
1941), or as a synonym of S. serrulatus (Sramek-Husek et al., 1962;
Negrea, 1983). Werestchagin (1912) writes that this variety differs
from the typical form in the higher head and the longer dorso-
posterior valve prominence. Statistical analysis of these metric
characters in type specimens shows that there is no morphological
hiatus between this variety and S. serrulatus (Orlova-Bienkowskaja,
1995a).

S. surekhae Rane is described from Jabalpur (India) (Rane,
1985a). The author does not point out any differences between this
species and S. serrulatus. Sharma & Sharma (1990) have studied the
types and sunk S. surekhae into the synonymy of S. serrulatus. This
conforms with my data, because the available specimens from
Jabalpur belong to the latter species.

S. serrulatus var. rotundifrons Brehm is also a synonym of S.
serrulatus (Sramek-Husek et al., 1962; Fléssner, 1972). In the opin-
ion of Brehm (1933) this variety described from Gao (Mal1) differs
from the typical S. serrulatus in its rounded head and the shorter
dorso-posterior valve prominence. The types are lost (Smirnov
N.N., personal communication). Statistical analysis shows that speci-
mens available from Niger do not differ from those from Europe in
these characters (Orlova-Bienkowskaja, 1995a).

S. capensis Sars was described from the vicinity of Knysna (South
Africa) (Fig. 41C). Sars (1895) writes that this species is closely

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 44S. semiserratus. A, parthenogenetic female, B, postabdomen, female, C, distal head part, female, D, outer side postabdominal claw, female,
E, postabdomen, male, F, distal part of head, male, G, male, H, ephippial female.

43

44

M.J. ORLOVA-BIENKOWSKAJA

Fig. 45S. mirabilis sp. nov., female. A, postabdomen, B, head, C, lateral view of holotype.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

45

SN SS

SS
SS
OSS,
= 2S s
=
(

ZA p
YAK {x
APIS

sal, N
AN

SoS
Bae
Se

=

>

Fig. 46 S. mirabilis sp. nov., female. A, endite of 2nd trunk limb, B, postabdominal claw, C, Ist trunk limb, D, antennule.

related with S. serrulatus but differs from it in head shape and the
absence of denticles on the posterior valve margin below the promi-
nence. Analysis of the head height in the type specimens reveals that
it does not differ in this respect from European specimens of S.
serrulatus (Orlova-Bienkowskaja, 1995a). The denticles of the pos-
terior margin are present in the types, but they are covered with a
semitransparent substance. I agree with the opinion of Fryer (1957)
that S. capensis is a synonym of S. serrulatus.

S. americanus Birge is described from North America. There is no
information about the types and type locality. The original descrip-
tion (Birge, 1878) reveals that this species is closely related with S.
serrulatus. In the opinion of Birge, it differs from the latter because
it has a rhomb-like ocellus and the postabdominal claw is covered
with denticles. Obviously, this is a misunderstanding because S.
serrulatus has the same characters.

S. serrulatus var. armata Brehm was described from Venezuela.
According to Brehm (1956), it differs from the typical form because
its antennules have ridges covered with denticles. But the typical
form has the same ridges and denticles, so this variety is a synonym
S. serrulatus (Fléssner, 1972; Negrea, 1983). The illustration in the
original description has the caption ‘S. serrulatus var. barbata’.
Obviously, this is an inadvertent error.

S. inflatus Vavra was described from Valdivia (Chile) (Vavra,

1900). There is no information about the types. Vavra does not point
out any differences between S. inflatus and S. serrulatus. He writes
that S. inflatus differs from S. capensis in the head shape, small
ocellus and general body shape. Daday (1905) supposes this name to
be asynonym of S. capensis, because he found some specimens with
intermediate characters in Paraguay. Michael & Sharma (1988)
believe it to be asynonym ofS. serrulatus. lagree with them because
the original description, provided with a good illustration, contains
all the important characters of the latter species.

S. kerhervei and §. aguabrankai, described from Sao Paulo
(Brasil), are not mentioned in recent literature. There is no informa-
tion about the types. The illustrations in the original description
(Bergamin, 1939), suggest that both types are juveniles with denticles
on the head and a row of denticles along the postabdominal claw.
The differences between these species and S. serrulatus are not
indicated. The available material from Sao Paulo does not differ
from the latter species (Orlova-Bienkowskaja, 1995a). Therefore S.
kerhervei and. aguabrankai are the junior synonyms ofS. serrulatus.

S. serrulatus var. productifrons, described from Sumatra (Stingelin,
1904), is also synonym of S. serrulatus (Sramek-Husek et al., 1962;
Negrea, 1983). The type material is lost (Frenzel, 1987). According
to Stingelin (1904), this variety differs from S. serrulatus, S. inflatus
and S. americanus by the elongate, pointed head and the large

46

fs F074 e

fr LOY OG Ler
SIG

00D,

Fig. 48S. latirostris. A, male, B, rostrum and antennule, male, C,
ephippial female.

M.J. ORLOVA-BIENKOWSKAJA

number of denticles. I believe that both features vary within
populations and cannot be diagnostic characters.

S. serrulatus var. mixta, described from Java, differs from the
typical S. serrulatus by the high head, large eye and elongate ocellus
(Grochmalicki, 1915). I have no material from Java, but specimens
from South-East Asia and Australia do not differ from European S.
serrulatus. Furthermore, the diagnostic characters of this form
varies within populations. I suppose this variety to be a synonym of
S. serrulatus. In addition, S. serrulatus var. mixtus is the primary
junior homonym of S. mixtus Sars, 1903.

S. serrulatus var. pelagicus Brehm was described from the pelagial
zone of a small lake in New Guinea (Brehm, 1959). The type
material, consisting of juvenile females, is probably lost (N.N.
Smirnov, personal communication). The author does not point out
any other differences between S. serrulatus var. pelagicus and
typical S. serrulatus except the head shape. I take S. serrulatus var.
pelagicus to be a synonym of S. serrulatus, because this character
varies within populations.

‘S. serrulatus var. spinosulus Stingelin, 1904’ mentioned by
Flossner (1972) as a synonym of S. serrulatus, does not exist. The
variety S. vetulus var. spinosulus Stingelin belongs to the subgenus
Simocephalus s. str.

S. semiserratus Sars, 1901
Fig. 44

Simocephalus semiserratus Sars, 1901: 23; S. capensis (S.
semiserratus Sars, 1901): Daday, 1905: 209; S. serrulatus (S.
semiserratus Sars, 1901): Kanduru, 1981: 72; Michael & Sharma,
1988: 83.

TYPE MATERIAL. Lectotype (designated by Orlova-Bienkowskaja
(1995a)): Brasil, Sao Paulo, Itatiba: CBS: 9 ad. (ZMO, F 9176).

REVISION OF SIMOCEPHALUS DAPHNIIDAE

SA
: We
A NS
i Jk Nuenyy
oA wu \\ Wl

XY B ga iy 4 Allin

A
A WV

Zope >
KES KEE SS

a

WWM" Z
LLL Z;

Fig. 49 S.latirostris appendages, female. A, Sth trunk limb, B, 4th trunk limb, C, Ist trunk limb, D, 3rd trunk limb, E, 2nd trunk limb, F, maxillule.

47

48 M.J. ORLOVA-BIENKOWSKAJA

SSS

WSS

Pn
EE

LE
Ze

WN

‘SD >
EWS
ws

Fig. 50S. latirostris. A, lateral view of Ist trunk limb, male, B, frontal view of Ist trunk limb, male, C, 2nd trunk limb, male, D, 5th trunk limb, male,
E, postabdomen, male, F, postabdomen, female, G, outer side of postabdominal claw, H, inner side of postabdominal claw, I, head pores.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Paralectotypes collected with lectotype: CBS: 9 9 Qad., 29 Q juv.
(ZMO, F 9176, F 9177), Argentina: MPA: 152 Qad., 109 Qjuv.,
62 Qe.,c'(ZMO, F 18438); MPA: 272 Qad., 22 Qjuv., 32 Ge.
(BMNH, 1901. 12. 12. 251-261).

MATERIAL EXAMINED

DIAGNOSIS. Measurements. @ 9 ad.: 1.0-2.0mm,2 Qe. 1.0-
1.5mm,o"": 0.7—1.0mm.

Female (Fig. 44). Dorso-posterior valve prominence small, sepa-
rated from the rest part of valves by shallow embayments. Its length
less than the diameter of circle inscribed in its contour. Denticles
cover less than 2 of posterior and less than 1/3 of dorsal margin. No
denticles on ventral margin. Ocellus short. Frons with denticles.
Morphology of trunk limbs unstudied, because it was impossible to
dissect the type material.

(Fig. 43). Lectotype, paralectotypes.

DISTRIBUTION. (Fig. 43) Argentina, Brasil (Sao Paulo).

REMARKS. Daday (1905) believes S. semiserratus and S. capensis
to be one species. Kanduru (1981) and Michael & Sharma (1988)
sink S. semiserratus into the synonymy of S. serrulatus. Sars (1901)
writes: ‘I am enabled to state with full certainty its [S. semiserratus]
distinctness from the European species [S. serrulatus]. In addition to
its somewhat larger size, it is easily distinguished by the far less
prominent posterior projection of the carapace, and somewhat dif-
ferent shape of the head. The marginal denticles, moreover, which in
S. serrulatus extend throughout the whole length of the hind margin,

>

@ S. latirostris © S$. heilongjiangensis

49

are in this species always limited to their uppermost part only’. It 1s
my belief that S. semiserratus is a separate species. First, statistical
analysis shows that it is separated from S. serrulatus in two pairs of
independent metric characters (Orlova-Bienkowskaja, 1995a). Sec-
ond, it differs from it in the marginal denticles of the valves. Third,
it occurs in South America sympatrically with S. serrulatus and
cannot be a geographical subspecies of this species.

S. mirabilis sp.nov.

Figs 45; 46

ETYMOLOGY. The name ‘Mirabilis’ means ‘Surprising’.

TYPE MATERIAL. Holotype: U.S.A., Alabama, Mobil Co., lower part
of Langan Park lake, 24. 5. 1987, leg. Fitzpatrik: MPA: 9 ad. (BMNH
1997. 1709). Paratypes: collected with holotype: MPA: 11 9 Qad.,
92 Qjuv. (BMNH 1997. 1710-1719); U.S.A., Oklahoma, Tulsa,
Oxley Nature Center, Mallard lake, 36°10'N, 98°W, 12. 6. 1991, leg.

Berner: MPA: 109 Qad., 29 Qjuv. (AC); Argentina, Rio Parana,

Catay pond, leg. Frutos: MPA: 49 Qad., 72 Qjuv. (AC).
MATERIAL EXAMINED. (Fig. 43) Holotype, paratypes.

DIAGNOSIS. Measurements. 9 9 ad. 1.0—1.2mm.

Female (Figs 45; 46). Dorso-posterior valve prominence moderate,
separated from the rest part of valves by moderate embayments. Its
length less than the diameter of circle inscribed in its contour.
Denticles cover less than 2 of posterior and less than 1/3 of dorsal

CEOS

oul

O S. lusaticus

@S. lusaticus & gs. heilongjiangensis

Fig. 51 Locations where the species of S. (Aquipiculus) were collected for this study or reported in literature.

M.J. ORLOVA-BIENKOWSKAJA

50

See y=
eg ESS

SS

SSS x

eps ss

as

(lille
Za

Fig. 52 S. heilongjiangenis, female. A, rostrum and antennule, B, parthenogenetic female, C, 2nd trunk limb, D, 3rd trunk limb, E, 5th trunk limb, F, Ist

trunk limb, G, 4th trunk limb, H, ephippial female (head omitted), I head pores.

REVISION OF SIMOCEPHALUS DAPHNIIDAE 51

SS

YEE

a,

\ Ayu
SSIS

SERS
WES

Zi;

AINE

\\AMAAS

\
\
Kz

a
\\Y
KK

AW

a

|
S A g

lus

Fig. 53S. heilongjiangenis. A, female, age variability, B, female, endite of 2nd trunk limb, C, female, postabdomen, D, female, head, E, male, lateral
view, F, male, antennule (E, F — after Shi & Shi, 1994).

32

M.J. ORLOVA-BIENKOWSKAJA

Fig. 54 S. Jusaticus. A, parthenogenetic female, B, parthenogenetic female ventral, C, ephippial female, D, male, E, parthenogenetic female, F,
parthenogenetic female, G, postabdomen, female, H, antennule, female, I, distal part of postabdomen, male, J, parthenogenetic female, K,
parthenogenetic female, ventral, L, 5th trunk limb, female, M, 2nd trunk limb, female. A-C, G, H, L, M after Behning, 1925, D, I, J, K after Herr, 1917,
E, F after Sramek-Husek et al., 1962. edge. No denticles on ventral edge. Ocellus elongate. Frons without denticles. Setae of 2nd and 3rd endite
prominence of 2nd trunk limbs as long as 0.6 and 0.4 of basal segment of plumose seta of 1st prominence respectively.

DISTRIBUTION. (Fig. 43) North and South America.

REMARKS. _ S. mirabilis differs from S. serrulatus and S. semiserratus
in the elongate ocellus and the absence of denticles on the frons.
However, I assign it to the subgenus S.(Coronocephalus), because of
the following characters: frons right-angled; antennule short, with
transversal ridges covered with denticles on inner side; postabdominal
claw with spines on proximal part of outer side and on inner side.

Subgenus S. (Aquipiculus) Orlova-Bienkowskaja,
1995
TYPE SPECIES. Simocephalus latirostris Stingelin, 1906

DIAGNOSIS. Both sexes (Figs 47-50). Frons rounded, without
denticles. Head shield depressed or flattened in middle. Head pores

present. Insertion of antennules at base of rostrum. Antennule long
in correspondence with long rostrum, with neither ridges nor denticles
oninner side. Aesthetes shorter than base of antennule. Postabdominal
claws without pecten of spines. Inner and outer side of claw with fine
setules. Anal bay of postabdomen straightened in the middle, its
proximal part without anal teeth.

Female. Dorso-posterior valve angle with large prominence. Valves
with dorsal keel. Posterior corner of ephippium with protuberance.
Ocellus short or slightly elongate, but always shorter than in S.
vetulus. Setae of 2nd and 3rd endite prominence of 2nd trunk limb as
long as 0.6—-0.7 and 1.4—1.6 of basal segment of plumose seta of Ist
prominence respectively. Postabdomen with 5—10 anal teeth on each
side. Supra-anal angle pointed.

Male. Supra-anal angle pointed. Vas deferens opening in middle of
anal bay or at base of supra-anal angle. Postabdomen with 5—7 anal

REVISION OF SIMOCEPHALUS DAPHNIIDAE

teeth on each side. Dorso-posterior valve angle with more or less
pointed prominence.

ETYMOLOGY. The subgenus is named Aquipiculus or ‘small water
woodpecker’ because all its representatives have a long rostrum
resembling a beak.

S. latirostris Stingelin, 1906
Figs 47-50

S. latirostris Stingelin, 1906: 187; Brandorff et al., 1982: 92; Orlova-
Bienkowskaja, 1995b: 46.

TYPE MATERIAL. Lectotype (designated by Orlova-Bienkowskaja
(1995b)): Paraguay, Riacho Negro, 3. 1894., leg. Ternetz, CBS in
poor condition: 9 ad., (MNO, III/24). Paralectotype: 9 juv., men-
tioned in the original description, has probably been lost.

MATERIAL EXAMINED. (Fig. 51) Lectotype and other specimens:
Argentina, Santa Fe, 23. 5. 1981: 21 2 Qad., more than 50 @ Q juv.,
312 Qe., 80 C(BMNH and AC). Brasil, Rio Negro, Anavilanas
Margen, 14. 9. 1979: 9 ad.

DIAGNOSIS. Measurements. 9 2 ad.: 1.0—1.8mm,c"o": 0.6-0.9mm.
Both sexes (Figs 47-50). Rostrum very long, rostrum length 6.4—
9.1% of body length in 2 9 ad., 5.4-7.7% ino’. Lateral margins of
rostrum elevated above central part. Antennule long, in correspond-
ence with long rostrum; about as long as rostrum. Head shield
deeply depressed in middle.

Female. Height 65-74% of length. Ephippium length 47-67% of
body length. Aesthetes shorter than antennule. Dorso-posterior valve
prominence in 9 ad. pointed. Denticles of valves very small, located
only on dorso-posterior prominence. No lateral prominences of
valves. Postabdomen with 5—9 (usually 7) anal teeth on each side.
Anal teeth gradually decreasing in size proximally, Sth tooth more
than half length of 4th.

Male. Vas deferens opening at base of supra-anal angle.

DISTRIBUTION. (Fig. 51) The tropics and subtropics of South and
Central America. Numerous records of S. /atirostris from Australia,
Malay Archipelago, South-EastAsia andAfrica are available. Johnson
(1963) supposes this species to be pantropical. However, according
to the descriptions and figures, the authors misuse the name S.
latirostris for S. heilongjiangensis.

REMARKS. _ S. latirostris was originally described at the beginning
of the 20th century (Stingelin, 1906) and was poorly known up to
now (Orlova-Bienkowskaja, 1995b). It was confused with next
species by several authors (see below).

Dumont (1983) supposes S. iheringi, described from Brasil, to be
a synonym of S. latirostris. The general body shape is rather similar
in these two species, and the valves of females are produced into a
sharp prominence in both species. But according to our data, S.
iheringi is the junior synonym of S. daphnoides and clearly differs
from S. latirostris in the pecten of the spines on the postabdominal
claw.

S. heilongjiangensis Shi, Shi, 1994
Figs 52-53

| Simocephalus latirostris: Fryer, 1957: 225; Johnson, 1963: 160;
Biswas, 1971: 115; Dumont & Van De Velde, 1977a: 81; Mamaril &
Fernando, 1978: 134; Kanduru, 1981: 65; Rajapaksa, 1981: 98;
Hossain, 1982: 112; Dumont, 1983: 103, Michael & Sharma, 1988:
80; S. heilongjiangensis Shi, Shi, 1994: 403; S. mesorostris Orlova-
Bienkowskaja, 1995b: 51.

53

TYPE MATERIAL. Holotype. Moershan Town (45°15'N, 127°30'E),
Shangzhi County, Heilongjang Prvince, 6.8.1990., leg. Shi
Xinlu. 9 ad. AllotypeC’and paratypes 302 Q and 100’ C'collected
with holotype (deposited in the Laboratory of Hydrobiology, Harbin
Normal Universiry, China).

MATERIAL EXAMINED. Type material of junior synonym S.
mesorostris: Holotype. The Philippines, Luzon, Bulacan near Chemi-
cal Plant, pond, 1.1976: CBS: 9 ad. (BMNH, 1995.753). Paratypes:
110 specimens (9 Qad., 9 Qjuv. and 9 Qe.) from The Philippines,
Indonesia, Malaysia, New Guinea, Australia, Viet-Nam, Sri Lanka
and India (BMNH, AC). More percise geographical data are pub-
lished elsewhere (Orlova-Bienkowskaja, 1995b). Other specimens:
139 specimens (2 Qad. and Q Q juv.) from Sudan (AC).

DIAGNOSIS. Measurements. 9 9 ad.: 1.2-1.9mm.

Female. (Figs 52; 53). Height 59-75% of length. Rostrum shorter
than in S. Jatirostris; length 3.3-5.7% of body length. Lateral
margins of rostrum below central part. Antennule shorter than in S.
latirostris, in correspondence with moderate size of rostrum, its
length about as long as rostrum. Aesthetes longer than antennule.
Depression of head shield shallow. Dorso-posterior valve promi-
nence in 2 rounded. Denticles of valves of moderate size, located
both on dorso-posterior prominence and on dorsal valve margin. No
lateral prominences of valves. Postabdomen with 5-8 (usually 6)
anal teeth on each side. Four distal teeth large, the rest extremely
small, 5th tooth less than half as long as 4th.

Male. Vas deferens opening at base of supra-anal angle.

DISTRIBUTION. The tropics of Australia, Malay Archipelago, Asia
and Africa (Fig. 51).

REMARKS. ‘The specimens from Africa differ from others in shorter
rostrum. However I believe that the African S. heilongjiangensis
does not belong to another subspecies because there is a consider-
able overlapping in this character (more than 25%) and there are no
other differences.

S. heilongjiangensis was confused with the closely related S.
latirostris by many authors (Fryer, 1957; Dumont & Van De Velde,
1977a; Rajapaksa, 1981; Kanduru, 1981; Hossain, 1982; Dumont,
1983; Michael & Sharma, 1988). I discovered that it is a separate
species (Orlova-Bienkowskaja, 1995b) and described it as S.
mesorostris. Shi & Shi (1994) came to the same conclusion inde-
pendently and named this species S. heilongjiangensis. This name
has the priority.

S. lusaticus Herr, 1917
Fig. 54

Simocephalus lusaticus: Herr, 1917: 58; Behning, 1923: 5; 1925:
526; Sramek-Husek et al., 1962: 259; Fléssner, 1972: 182; Kaminski,
1975: 89.

TYPE MATERIAL. Syntypes: East Europe, Silesia, ponds near Werda,
27. 7. 1913 (12 specimens), 5. 9. 1913 (3 specimens), “false ponds’,
10. 8. 1913 (6 specimens). I do not know in what museum these
syntypes were deposited, or whether they still exist.

MATERIAL EXAMINED. None.

DISTRIBUTION. (Fig. 51) East Europe: Silesia, Czech Republic,
Slovakia, Poland, Russia: Wolga basin. Chiha: Heilong Province.
Manujlova (1964) reports this species from the Caucasus. Obvi-
ously, this is a misunderstanding, because she refers to a book
(Behning, 1941) which contains no such information.

DIAGNOSIS. Measurements. 9 9 ad.: 1.5-3mm,C C’about 1mm.

54

Both sexes (Fig. 54). Rostrum shorter than in S. latirostris; its lateral
margins below central part. Antennule shorter than in S. Jatirostris,
about as long as or a little longer than rostrum. Depression of head
shield shallow.

Female. Aesthetes about as long as antennule. Dorso-posterior valve
prominence rounded or pointed. Denticles of valves very small,
located only on dorso-posterior prominence. 2-8 pairs of lateral
prominences on valves. Postabdomen with 7—10 anal teeth on each
side. Anal teeth gradually decreasing in size proximally.

Male. Vas deferens opening in middle of anal bay.

REMARKS. Judging from the available descriptions (Herr, 1917;
Behning, 1925; Sramek-Husek et al., 1962; Flossner, 1972; Kaminski,
1975), S. lusaticus has all the diagnostic characters of the subgenus
Aquipiculus. It differs from all other species of the genus in having
lateral prominences on the valves.

NOMINA DUBIA AND SPECIES
TRANSFERRED TO THE GENUS DAPHNIA

S. aegyptiacus (Fischer, 1860) has been described from the viciniy
of Alexandria (Egypt). There is no information about the type
material. The original description (Fischer, 1860) is rather detailed
and allows us to attribute this species to Simocephalus s. str. I think
that contrary to the opinion of Richard (1894) and Sramek-Hukek et
al. (1962), it is not a synonym of S. vetulus because it has a large
dorso-posterior valve prominence. Behning (1941) supposes this
species to be a synonym of S. elizabethae, but I believe that the latter
differs from all species including S. aegyptiacus in the shape of the
ventral head margin. Unfortunately, it is impossible to conclude
whether S. aegyptiacus is a separate species or a synonym of S.
mixtus or S. vetuloides.

S. cacicus Moniez, 1889 has been described from Lake Titicaca.
There is no information about the type material. To judge from the
original description (Moniez, 1889), this species belongs to
Simocephalus s. str. But it is difficult to say whether it is in fact a
separate species.

S. vetulus spinosulus Stingelin, 1904 has been described from the
Hawaiian Islands. Stingelin (1904) points out that this variety differs
from the typical form because ‘es zeigt sich die Tendenz zur Bildung
einer schwachen Shalenprominenz’. No illustration is given. The
type material has been lost (Frenzel, 1987). Some authors regard S.
vetulus var. spinosulus as a synonym of S. vetulus (Floéssner, 1972;
Frenzel, 1987). The original description shows that this variety
belongs to Simocephalus s. str., but it does not contain any characters
important for the identification of species within this subgenus.
Material from the Hawaiian Islands is necessary to decide this
question.

S. serrulatus var. nudifrons Delachaux, 1918 has been described
from the Andes (Peru). The type was probably not indicated. The
original description (Delachaux, 1918) is without an illustration and
contains only one character: the absence of denticles at the head in
all specimens. That means that it is not S. serrulatus because the
denticles are the main character of this species. But this information
is not enough to permit identification.

S. postidelivis Lai & Li, 1987 was described on the base of fossil
ephippia from the Tertiary of China (Lai & Li, 1987). Referring to
the photographs, these ephippia do not differ from ephippia of recent
species. It is impossible to identify either the species or even the
subgenus.

Two species assigned to the genus Simocephalus belong, in fact,
to the genus Daphnia, as is evident from their original descriptions

M.J. ORLOVA-BIENKOWSKAJA

(Studer, 1878; Brady, 1918). This is S. gelidus Brady, 1918 =
Daphnia gelida comb. nov. and S. intermedius Studer, 1878 = D.
intermedia comb. non.

KEY TO THE SUBGENERA AND SPECIES OF
SIMOCEPHALUS

Figs 55—59 (picture numbers correspond with couplets in the key)

1. Fig. 55. 9&0": Postabdominal claw without spines. Inner and outer side
of claw with fine setules (A). Frons rounded, without denticle (B)

— Fig.55. 9 &o": Postabdominal claw with basal pecten of spines at outer
side. Inner side and distal part of outer side with fine setules (C). Frons
rounded (D) or pointed (E), without denticlesS. (Echinocaudus) subgen.
ICD) corcnncocccecoeccencnceotco- on eden becencc oreo rconcecesnor peseeRenebenerenccnoncneserencencecscen 10

— Fig. 55. 9&0": Postabdominal claw with spines on inner side and in
proximal part of outer side. Basal part of outer side with fine setules (F).
Frons right-angled, with denticles, or very rarely without denticles (G)
(American species S. mirabilis) S. (Coronocephalus) Orlova-Bien-
kowskaya; L995 <2... s.cses. se eteebeteslcd leek nck ceeeets ee 16

2. Fig. 55. 9: Ocellus elongate (H) (exception: North American species S.
punctatus). Anal bay with small anal teeth (I). Dorso-posterior valve
angle without prominence (J) or with comparatively small prominence
(K). o&: Vas deferens opening on top of supra-anal angle (L).
Simocephalus’s. Sties2tha eS. ee a, ce ee eee 3

Fig. 55. 9 : Ocellus short (M). Anal bay without anal teeth (N). Dorso-
posterior valve angle with large prominence (O). Oo: Vas deferens
opening in middle of anal bay or at base of supra-anal angle (P)
S. (Aquipiculus) Orlova-Bienkowskaja, 1995 .........:cccccsceseeeeeeeeeeees 8

3. Fig. 56. 9: Ocellus point-like (B). Dorso-posterior valve angle rounded,
without prominence (A). Occurs in North America ............:::c:eeee
suedul ton icsthsstarancectdvscvedteaachuvdevederstusnseessee teerert oases S. punctatus sp.nov.

— Fig. 56.2: Ocellus elongate (C). Dorso-posterior valve angle of differ-
GME SMAPS. o.cecboece se eesd ava subda ce cbeu ance Paccgueceaect eves ca oe eee 4

4. Fig. 56.2: Dorso-posterior valve angle with very small prominence
(D). The most common European species. Occurs also in North Africa
SP ae ea te Ue aah sR S. vetulus (O.F. Miiller, 1776)

— Fig. 56.9: Dorso-posterior valve angle with larger prominence (E)

— Fig. 56.2: Depression of ventral head margin near rostrum shallow,
sometimes absent (G). Species occur in Australia, Tasmania and New
GUMS ae pses te ehe vecarse cane ccas Sevan saves eae ces a ids bapessee ye wakes ee eee 7

6. Fig. 56.9: Diameter of dorso-posterior valve prominence exceeds its
length (H). Dorsal valve margin protruding backward (I) ...............+.-
Fy eRe RE CRE EEE CERT era S. mixtus Sars, 1903

— Fig. 56. 9: Diameter of dorso-posterior valve prominence less than its
length (J). Dorsal valve margin not protruding backward (K). Occurs in
BAS term SIDEMAN rerescs-c cere teens See ee S. vetuloides Sars, 1898

7. Fig. 56.9: Dorsal valve margin protruding backward strongly (L)
Jadot chavs ous ccca@tter a uravicsaacakasiaedeaaawMenes rane oe een cutee S. gibbosus Sars, 1896

— Fig. 56.9: Dorsal valve margin not protruding backward (M)...........
b AO a Marat hn Rt in oo MRED comuccente S. elizabethae (King, 1853)

8. Fig.57. 9 & &: lateral prominences on valves present (A). Rare species.
Occurs in East Europe and China..... ..........::cesceecceeeeeeeee S. lusaticus
Herr, 1917

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig.55 Key to subgenera. Numbers correspond with couplets in the key.

S.

P

(Aquipiculus)

55

56 M.J. ORLOVA-BIENKOWSKAJA

Q

¥
“A
(e °

ee
D Tay eee
S. vetulus 5

=
(

6 F S

a 7 G
: ae
J J
B
G *
7 *
if
if K L M
S. mixtus S. vetuloides S. gibbosus s. elizabethae

Fig. 56 Key to Simocephalus s. str. Numbers correspond with couplets in the key.

REVISION OF SIMOCEPHALUS DAPHNIIDAE

Fig. 57 Key to S. (Aquipiculus). Numbers correspond with couplets in the key.

10.

Wile

iS:

S. lusaticus

S. latirostris

Fig. 57. 2 & Oo’: No lateral prominences on valves (B) .........::.:00000: 2)

Fig. 57. 2: Rostrum very long, its lateral margin elevated above central
part (C). Dorso-posterior valve prominence pointed (D). Occurs in
BU OULUENPANIME LCA a2. .vscecssssicansteasterceiseaseetetece S. latirostris Stingelin, 1906

Fig. 57. 2: Rostrum of moderate size, its lateral margin below central

part (E). Dorso-posterior valve prominence rounded (F). Occurs in

Australia, Malay Archipelago, Asia and Africa. ..........ccceceeseeeneeeees
SR ceraiarssccvacssneataesterscusasoatecassute S. heilongjiangensis Shi, Shi, 1994

Fig. 58. 9: Frons rounded (A). One supra-anal angle (B)............... 1]

Fig. 58.2: Frons pointed (C). Two supra-anal angles (D)
BM (CLGULLT OST ALES) SPECIES, SLOP) .cecascesscaecscefaeseccce 2-e-es-nseneeteteeooecace 14

Fig. 58. 2: Ventral head margin very convex (E). Spines of basal pecten
of postabdominal claw well-spaced (F). Occurs in New-Zealand
PRR cn nso astaa cer evasaakesv eevee S. obtusatus (Thomson, 1878)

Fig. 58.9: Ventral head margin almost straight (G). Spines of basal
pecten of postabdominal claw close-set (H) .........:eccceseeeseeseeeeeee 12

Fig. 58. 9 : Dorso-posterior valve angle with large pointed prominence
(Occurs stay AmmertGai ects ose secede cere S. daphnoides Herrick, 1883

Fig. 58. 9: Dorso-posterior valve angle with rounded prominence or
VPMELTOLULE TORO OAMIT EINES: (()) le scncceccessaconece ho aecoccedoaseceeccuproes oo SbauRoeNeAocEEeRCE 13

Fig. 58.9: Basal pecten of postabdominal claw of 8-12 spines of
MOIETIES SIVA. (O59) rncccacoocscencopenntenarenseen S. exspinosus (De Geer, 1778)

Fig. 58. 9: Basal pecten of postabdominal claw of 20-25 small spines
(L). Occur in Europe and Asia .................- S. congener(Koch, 1841)

Si

S. heilongjiangensis

Fig. 58. 9 : Dorso-posterior valve angle smooth, rounded, without promi-
nence (M). Occurs in Australia .............. S.victoriensis Dumont, 1983

Fig. 58. 2 : Dorso-posterior valve angle with distinct prominence covered
watinidemtiel esi (IN) ie sececesce ccoqecxssuay eeate sc ovevonteecase cuca beesvasesvanot moseseoeeses 15

Fig. 58.2: Dorso-posterior valve prominence separated above and
below by deep, wide depressions. Diameter of circle inscribed in it
moderate (O). Occurs in Africa ..............00- S. brehmi Gauthier, 1939

Fig. 58.9: Dorso-posterior valve prominence separated above and
below by shallow, wide depressions. Diameter of circle inscribed in it
larcer (2) aOccurs inrAustraliavandiAstatee scorer eeece ee ceeeree eee

Fig. 58.9: Dorso-posterior valve prominence separated above and
below by deep, narrow depressions. Diameter of circle inscribed in it
small (Q). Occurs in North America .......... S. rostratus Herrick, 1884

Fig. 59.2: Ocellus elongate. Frons without denticles (A). Occurs in
SINCE CAVERN a oat ees cee ans ci veanceceeeep ie gaan ate cues S. mirabilis sp. nov.

Fig. 59. 2: Ocellus short. Frons with denticles (B) .........:..:::cc00 17

Fig. 59. 9 : Dorso-posterior valve prominence large, separated from rest
of valves by deep embayments (C). Its length exceeds diameter of circle
inscribed in its contour (D). Denticles cover ventral, posterior and more
than 1/3 of dorsal margin. 0.0.2.0. S. serrulatus (Koch, 1841)

Fig. 59. 2 : Dorso-posterior valve prominence small, separated from rest
of valves by shallow embayments (E). Its length less than diameter of
circle inscribed in its contour (F). No denticles on ventral margin.
Denticles cover less than ¥2 of posterior and less than 1/3 of dorsal
margin. Occurs in South America ............. S. semiserratus Sars, 1901

58 M.J. ORLOVA-BIENKOWSKAJA

11 14

Ss. (acutirostratus

ase (jo. LN

¢d y \

ye ss _ I? ne
ae

§. victoriensis
S. daphnoides
ey \\
\
ia
>
aa \\

O ry

H

S. brehmi

S. rostratus

f S. congener :
S. exspinosus S. acutirostratus

Fig. 58 Key to S. (Echinocaudus). Numbers correspond with couplets in the key.

REVISION OF SIMOCEPHALUS DAPHNIIDAE 59

16

* ) a
Bi a 7st »

S. mirabilis

=
=

semiserratus

serrulatus

Fig. 59 Key to S. (Coronocephalus). Numbers correspond with couplets in the key.

60

CHECK LIST OF SIMOCEPHALUS

Subgenus Simocephalus s. str.

il.

ges Pe

6.

S. vetulus (O.F. Miller, 1776) (Daphne vetula)
Daphnia sima O.F. Miller, 1785

Monoculus nasutus Jurine, 1820

S. vetulus var. angustifrons Lilljjeborg, 1900

S. vetulus var. brandti Cosmovici, 1900 syn. nov.
S. vetulus gebhardti Ponyi, 1955

S. mixtus hungaricus Ponyi, 1956

S. elizabethae (King, 1853) (Daphnia Elizabethae)
S. dulvertonensis Smith, 1909

S. gibbosus Sars, 1896

S. vetuloides Sars, 1898

S. mixtus Sars, 1903

S. corniger Methuen, 1910 syn. nov.

S. beianensis Shi, Sbi, 1994 syn. nov.

S. punctatus sp. nov.

Subgenus S. (Echinocaudus) subgen. nov.

is
8.

S. obtusatus (Thomson, 1878) (Daphnia obtusata)
S. daphnoides Herrick, 1883

S. ITheringi Richard, 1897 syn. nov.

S. fonsecai Bergamin, 1939 syn. nov.

S. fonsecai var. sinucristatus Bergamin, 1939 syn. nov.

S. (exspinosus) species group

9. §. exspinosus (De Geer, 1778) (Monoculus exspinosus)

10.

Daphnia australiensis Dana, 1852

S. sibiricus Sars, 1898 syn. nov.

S. productus Sars, 1903

S. himalayensis Chiang & Chen, 1974 syn. nov.
S. vamani Rane, 1985

S. congener (Koch, 1841) (Daphnia congener)

S. (acutirostratus) species group

iil

S. acutirostratus (King, 1853) (Daphnia Elizabethae vat.

acuti-rostrata)

12.

13. S. brehmi Gauthier, 1939 stat. nov. (Simosa acutirostrata

S. paradoxus Schodler, 1877
S. vidyae Rane, 1983

S. vidyae gajareae Rane, 1986
S. victoriensis Dumont, 1983

brehmi)

14.

S. acutifrons Johnson, 1954 syn. nov.
S. rostratus Herrick, 1884

Subgenus S. (Coronocephalus) Orlova-Bienkowskaja, 1995

IS),

S. serrulatus (Koch, 1841) (Daphnia serrulata)
D. brandtii Fischer, 1848

D. intermedia Lievin, 1848

. americanus Birge, 1878

. capensis Sars, 1895

. inflatus Vavra, 1900.

serrulatus var. productifrons Stingelin, 1904
serrulatus vat. montenegrinus Werestchagin, 1912
. serrulatus var. mixta Grochmalicki, 1915

. serrulatus var. rotundifrons Brehm, 1933

. kerhervei Bergamin, 1939

. agua-brankai Bergamin, 1939

. serrulatus var. armata Brehm, 1956

. serrulatus var. pelagicus Brehm, 1959

. surekhae Rane, 1985

AnRNRNANNANNAY

M.J. ORLOVA-BIENKOWSKAJA

16. S. semiserratus Sars, 1901
17. S. mirabilis sp. nov.

Subgenus S. (Aquipiculus) Orlova-Bienkowskaja, 1995
18. S. latirostris Stingelin, 1906
19. S. lusaticus Herr, 1917
20. S. heilongjiangensis Shi, Shi, 1994
S. mesorostris Orlova-Bienkowskaja, 1995

Nomina dubia
Daphnia aegyptiaca Fischer, 1860
S. cacicus Moniez, 1889
S. vetulus spinosulus Stingelin, 1904
S. serrulatus var. nudifrons Delachaux, 1918
S. postidelivis Lai & Li, 1987

Species transferred to the genus Daphnia
S. gelidus Brady, 1918 = Daphnia gelida comb. nov.
S. intermedius Studer, 1878 = D. intermedia comb. nov.

ACKNOWLEDGEMENTS. This work could not have been completed with-
out the help of many colleagues. I am deeply obliged to N.N. Smirnov and
N.M. Korovchinsky for valuable remarks and submitted material. | am
grateful to the following persons for generously allowing me to borrow
material from collections in their care: M.E. Christiansen (ZMO), Sh. Halsey
(BMNH), L.A. Kutikova, I.P. Nikolaeva (ZI), M. Peltier (MNO), R. Joque
(MCA), N.L. Bruce (ZMC), P.B. Berents (AM), W. Zeidler (SAM), R.
Wilson (MV). Some series of Simocephalus were collected by D. Berner, A.
Litt, M.B. King, D. McNaught, A.V. Monakoy, V.F. Matveev, I. Mirabdullaev,
A.V. Makrushin, T.A. Britaev, H. Dumont, K.H. Fernando and L. de Meester.
Their cooperation is gratefully acknowledged. I am also grateful to A.O.
Bienkowski for the help in the work.

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Bull. nat. Hist. Mus. Lond. (Zool.) 64(1): 63-89 Issued 25 June 1998

Structural niche, limb morphology and
locomotion in lacertid lizards (Squamata,
Lacertidae); a preliminary survey

E.N. ARNOLD
Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, UK

CONTENTS

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Phylogenetic relationships of the Lacertidae .................::cceeee
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Overview of lacertid structural niche space ..........:..ssccseseeeeeeees
Structural habitats occupied by groups within the Lacertidae
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The manus in ground dwelling lacertids from open situations .............
The manus in lacertids regularly climbing on steep open surfaces ......
ChraractemSiics Ol the Lectin Otlen LACTIS i .cc.cesereteceessessteresecescsbensseaeerens
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Other hind limb gaits in ground dwelling lizards — continuous gearing
Movements of the foreleg in ground dwellers .............:c:sesceeteeseeereeneeeees
Functional aspects of the limbs and feet of ground dwelling lacertids ...
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Functional aspects of the limbs and feet of specialised climbing lacertids
Climbing in specialised ground dwelling species
Concluding remarks
Acknowledgements
I ESSIEN See cach aedcnatcopechcecee Ace AeRE Ce RGAE Asch ce ba EAE LARC Hace Oar eR REE SSS pcr coe AES CEA CRANEE EE SoA RecA REO ROO eRe PEPE Ce REO eee

© The Natural History Museum, 1998

64

E.N. ARNOLD

SYNOPSIS. Lacertid lizards occur in a wide range of structural habitats and 1) may be found on open ground-ranging from
rocky surfaces, gravel and soil to firm and loose sand, or 2) be associated with quite dense low ground vegetation, or 3) climb
through and over vegetation matrixes such as tall grass and herbs, bushes and tree canopy, or 4) climb on more or less continuous
steep or even overhanging surfaces such as rock faces and tree boles. Some forms are largely confined to one of these broad
structural niches while others occur more widely, but the locomotory requirements of the habitat occupied are usually reflected
in morphology. The body may show some elongation in taxa that regularly travel through complex interstices of vegetation and
similar habitats while it is quite short in forms that live on open ground; the tail is often extremely long in matrix climbers and
may help spread weight in these.

When forelimb span/hindlimb span is plotted against hindlimb span/ head + body length, lacertids group substantially
according to their structural niche. In general, disparity in span of the limb pairs increases with hindlimb length: long hind and
short fore limbs occur in open ground forms, shorter more equal limb pairs in climbers in matrixes and on continuous surfaces,
and very short subequal limbs in forms associated with dense low ground vegetation. Sexual dimorphism in limb proportions is
found in some taxa, females having shorter and usually more equal limbs, but it is not known if this reflects differences in
structural habitat. Proportions of limbs may vary considerably among close relatives as do their growth patterns, indicating that
they may be easily modified by natural selection. Variation also occurs in the relative lengths of the femur and crus.

On open ground, long hind limbs can be effectively deployed and provide a high-gear system that contributes most locomotor
thrust and produces high speeds. In dense ground vegetation etc. the forelimbs are probably used more and the short legs can be
deployed effectively in confined spaces. Among matrix climbers, the same advantages can apply and in climbers as a whole the
relatively short hind limbs provide low-gear thrust against gravity while the forelimbs also contribute and, in addition, prevent the
foreparts falling away from steep surfaces.

The caudifemoralis muscle, which is the main retractor of the thigh, has its origin in the proximal tail with multiple heads
attached mainly to the non-autotomic pygal vertebrae. the number of these vertebrae increases in advanced ground-dwellers and
this may enhance effective size of the muscle and hence limb power. In many lacertids, the most posterior part of the muscle, which
is slender, extends a short distance on to the autotomic vertebrae and may consequently be lost during tail shedding.

The complex movements of the hind limbs in ground-running lacertids are described including their effects in ameliorating the
supposed problem of crural rotation. In the hind feet of open ground dwellers, the metatarsals and toes 14 increase in length,
allowing the long claws which act like athlete’s spikes to gain purchase over a broad area. At the end of a stride, ground lizards
may rise on to the tips of toes 2-4 of a single foot, something permitted by robust phalanges and restrictions on mesial flexion at
the toe joints; toe 5 is scarcely used and often miniaturised. The gait of lacertids varies according to the degree the crus and foot
are extended forwards, providing a variable gear system that alters as the lizard gains speed; however on very steep surfaces
climbing species rarely extend the leg fully.

In climbers on open surfaces, metatarsal 3 is longest allowing toe 3 to be deployed anteriorly or posteriorly . Toes are often
spread broadly and a positive grip obtained by a system of digital kinking that allows them to shorten after claw insertion. While
kinking is beneficial to climbing lizards, its exact pattern may be partly arbitrary and varies considerably across taxa. Slender
phalanges and robust tendons reflect the fact that toes of climbing lizards are often under tension. Upward thrust is maximised
by maintaining the grip of the feet as long as possible. This is facilitated by a system that allows differential flexion of the digits
and by substantial flexibility of their joints.

The morphologies that facilitate each of these two contrasting kinds of locomotion place constraints on the other. Most ground
dwellers have great difficulty ascending steep surfaces, while climbers do not rise on the tips of the hind toes when running on
the ground. Feet of forms using dense ground vegetation and of matrix climbers have their own characteristics but respectively
tend to resemble the two kinds described above. Many lacertids show some intermediacy in limb morphology that reflects the
conflicts and compromises of moving in more than one type of habitat.

The mode of locomotion of the immediate ancestor of modern lacertids is unknown but some degree of climbing is widespread
in the primitive Palaearctic assemblage, even though a number of ground forms also exist. In the Armatured clade some climbing
appears to be primitive and there are clear shifts: to specialised climbing on open surfaces, to matrixes, to using dense ground
vegetation and finally to open ground.

INTRODUCTION

Locomotion of lizards has recently become a fashionable area of
enquiry, particularly locomotor performance and its relationship to
the ecology and morphology of the forms concerned (see for
instance summary by Garland & Losos, 1994). While performance
has often been studied in detail and comparative ecology is fre-
quently well understood, morphology has often been limited to
simple measurements, especially hind limb length. Little has been
written in this context about foot morphology and how this affects
locomotion, the main exceptions being for specialised feet such as
the adhesive pads of anoles and geckoes (see for example Russell,
1976)

The 230 or so species of lacertid lizards occupy a wide range of

structural niches and, although they are morphologically quite uni-
form in many respects, exhibit substantial variation in limb
proportions and structure of the feet, features that are often used in
systematics (see for instance Boulenger, 1920, 1921). Informal
observations suggest that limb and foot differences confer perform-
ance advantages in locomotion in particular habitats. This probable
correlation between structure and function is explored here, and
phylogenetic information used to get some idea of historical shifts in
habitat and morphological features important in locomotion. As will
become apparent the topic as a whole has many aspects and ramifi-
cations, all of which are susceptible to detailed and rigorous
exploration. The intention of this article is to provide a preliminary
overview that will allow such investigations to be placed in a broad
context.

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

PHYLOGENETIC RELATIONSHIPS OF THE
LACERTIDAE

The successively distant outgroups of the Lacertidae appear to be the
1. the Tetioidea, consisting of theTeiidae and the Gymnophthalmidae;
2. the Scincoidea consisting of the Scincidae, Cordylidae,
Gerrhosauridae and probably the Xantusiidae; 3. the Anguimorpha
(Estes, De Queiroz & Gauthier, 1988; Gauthier, pers. comm.).
Phylogenetic hypotheses within the family based on morphology
have been discussed elsewhere (Arnold, 1989a) and some of these
relationships have been modified and extended on the basis of
investigations using mitochondrial DNA sequence (Harris, Arnold
& Thomas, submitted a). The phylogenies of particular groups of
lacertids have also been explored (Arnold, 1989b, 1991, 1997;
Harris, Arnold & Thomas, in press, submitted b—d).

DNA evidence suggests that the most basal branch within the
family may comprise the sister genera Gallotia and Psammodromus.
There may then be a dichotomy into two large clades (Fig. 1), one
consisting of relatively primitive mainly west Palaearctic taxa the
other of forms that possess a combination of a complex supporting
structure in the hemipenis, the armature, and a usually derived ulnar
nerve condition (Arnold, 1989a). This Armatured clade contains
Omanosaura and all the Afrotropical lacertids and some morpho-
logically derived genera found in the arid parts of the Saharo-Eurasian
region (Fig. 2). While relationships within the Armatured clade are
reasonably well resolved, largely on the basis of morphology, those
in the primitive west Palaearctic assemblage are less clear. This
group can be referred to as Lacerta and its allies, and consists of a
paraphyletic Lacerta from which is derived Algyroides and Podarcis.
The east Asian Takydromus may be sister taxon to Lacerta and its
allies but the evidence for this is not strong and for present its
relationships to this group and the Armatured clade are best regarded
as unresolved. A number of assemblages within Lacerta and its
allies can be tentatively recognised (Fig. 1).

1. Lacerta agilis group: L. agilis, L. bilineata, L. media, L.
pamphylica, L. schreiberi L. strigata, L. trilineata, L. viridis

2. L. lepida group:L. lepida, L. pater, L. princeps and L.
tangitana.This assemblage has often been associated with the L.
agilis group on the basis of morphology (Boulenger, 1920;Arnold,
1973, 1989a) and, although immunological data do not suggest
such a relationship, DNA sequence does give some admittedly
weak support.

3. Lacerta vivipara.

. Podarcis and its relatives Lacerta andreanszkyi and the sister

species, L. dugesii and L. perspicillata.

. L. saxicola group, consisting of Lacerta saxicola and generally
similar ‘archaeolacertas’ in the Caucasus area including L.
chlorogaster, L.derjugini and L. praticola. L. brandtii may be
related to this assemblage.

6. Northwestern ‘archaeolacertas’. Lacerta bonnali and the similar

L. aranica and. aurelioi, L. horvathi, L. monticola, L. mosorensis.

7. Algyroides

8. Southern ‘archavolacertas’: L. bedriagae, L. cappadocica, L.
danfordi group (Lacerta anatolica, L. danfordi, L. oertzent), L.
bedriagae, L. graeca, L. kulzeri, L. laevis and L. oxycephala.
Unlike the other groupings, there is no evidence that these species
consititute a clade.

9. L. parva and L. fraasii. Although morphology suggests these
forms may be related to Psammodromus and Gallotia (Arnold,
1989a), mDNA sequence provides no support for this arrange-
ment, suggesting instead a relationship to L. danfordi.

a

Nn

65

STRUCTURAL NICHES OF LACERTID
LIZARDS

Overview of lacertid structural niche space

The spatial niches that lacertid lizards occupy differ in both
microclimate and their structural properties (Arnold 1973, 1987).
The main structural variables include the nature, continuity and
angle of the surfaces on which the lizards are active. Essentially the
range of structural niches occupied forms a continuum. Many
species occur on open ground that is flat or gently sloping. The
substratum may be gravel or small stones, earth or sand or some
mixture of these. Sandy substrata may be firm, soft, or even the
mobile slip faces of dunes. In some situations the ground may be
entirely bare but there is frequently cover of varying density and
patchiness, consisting of grass or other herbaceous vegetation,
bushlets or bushes. Lizards may take refuge among such plants when
disturbed and, when cover is more continuous, some forms may
spend much time in the interstices of vegetation near the ground. The
interstices among pebbles or small rocks constituting scree may be
occupied in a similar way. Some lacertids regularly climb high
among vegetation including the twiggy matrixes of bushes and tree
canopies, or flimsy plant matter such as herbs or high grass, over the
top of which some forms may run. In contrast, many species climb
in a different kind of situation characterised by continuous sloping
or vertical surfaces, for instance rock faces, large boulders and tree
boles and branches.

Some lacertid species specialise in a relatively narrow and homo-
geneous section of the habitat continuum occupied by the family as
a whole. Others may spend time in more than one part, for instance,
Podarcis muralis occurs on occasion on bare ground and among low
vegetation but also climbs in hedges, on boulders and rock faces and
even tree boles. Similarly, Psammodromus algirus is cursorial on the
ground but also climbs in dense often spiny vegetation.

Structural habitats occupied by groups within the
Lacertidae

Few quantitative data exist on differences in structural niche between
lacertid taxa, but less formal information is available for many
forms. This is briefly summarised here. Citations often refer to
summaries rather than scattered primary sources. Information on
many west Palaearctic taxa can be found in Bohme, 1981, 1984,
1986; Arnold, 1987 and Arnold & Burton, 1978). The notes on
lacertid habitats by R.H.R. Taylor cited below were made in north-
ern Somalia in the 1930s and are deposited in the archives of the
Reptile Amphibian Section, Natural History Museum, London.

Taxa are discussed in the approximate order in which they appear
on the estimates of phylogeny in Figs. | and 2.

Primitive Palearctic forms

Psammodromus (SW Europe, NW Africa)

P. algirus often occurs on the ground in dry vegetated places but, as
noted, also climbs extensively in bushes etc. The three species that
constitute the Psammodromus hispanicus clade are strictly ground
dwelling usually in places with patches of low dense vegetation in
which they take refuge.

Gallotia (Canary islands)
All species occur extensively on the ground but also climb effec-
tively.

66

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E.N. ARNOLD
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Fig. 1 Estimate of phylogeny for the Lacertidae. Relationships among many primitive Palaearctic taxa are largely unresolved. For contents of assemblages
within the paraphyletic genus Lacerta see p. 65. As it is shown here the Lacerta saxicola group is not a clade.

Takydromus (E Asia).

This genus is made up of two sister clades, the subgenera Takydromus
and Platyplacopus, with T: amurensis either basal to both or basal
within the subgenus Takydromus (Arnold, 1997). Basal species in
the genus Zakydromus tend to be mainly ground dwelling but in each
of the two constituent clades there is progressive shift to extensive
climbing in flimsy vegetation such as grass and herbs. However,
various morphological features likely to give performance advan-
tage in such situations occur throughout the genus, which suggests
that it may have been ancestrally climbing. If so there may have been
a shift to a more ground-dwelling life mode and then two reversions
to climbing (Arnold, 1997).

Lacerta agilis group (Europe, SW Asia)

Ground-dwelling and climbing especially in brambles (Rubus) and
similar vegetation. L. agilis is more ground dwelling than the other
species.

Lacerta lepida group (SW Europe, NW Africa, SW Asia)
Ground dwelling and climbing.

Lacerta vivipara (Europe eastwards to Sachalien)
Ground dwelling in and around herbaceous and heathland vegeta-
tion.

Podarcis (NW Africa, S and central Europe)

P. hispanica, and P. muralis are frequently active.on the ground but
also climb extensively, especially on rocky surfaces. Other species
of Podarcis climb to varying extents but usually less than most
populations of P. hispanica and P. muralis, spending a larger propor-
tion of time on or close to the ground. This trend is particularly
apparent in such forms as Podarcis sicula, P. melisellensis and
especially P. taurica. P. sicula often runs considerable distances

across open areas. (Sources: Bohme, 1986; Arnold, 1987; Arnold &
Burton, 1978; pers. obs.).

Lacerta andreanskyi (Atlas mountains of Morocco)

This high altitude species has been observed on flat or gently
sloping areas of scree with many interstices and often some veg-
etation (Busack, 1987; pers. obs.). It 1s active on the irregular
surfaces of such situations but also spends considerable time trav-
elling through the spaces between the stones, something that can
be confirmed by providing captives with a similar structural envi-
ronment. The lizards pass through very narrow gaps and also often
make sharp turns in confined spaces. L. andreanszkyi make use of
the thermal properties of the scree column to maintain their body
temperature when the sun disappears. At such times, they retreat
into the layer of stones immediately below the surface which still
retains heat, descending further into more secure refuges when
these cool (pers. obs.).

Lacerta dugesii and L. perspicillata (Madeira, NW Africa)

Both these species climb to a considerable extent on open usually
rocky surfaces, a trend that is better developed in L. perspicillata
(pers. obs.).

Lacerta saxicola group (Caucasus area and adjoining north Iran,
Iraq and Turkey)
Lacerta saxicola and generally similar species in the Caucasus and
adjoining areas occur especially on rocky exposures of various kinds.
L. chlorogaster of north Iran etc is distinctive in being found in forest
where it climbs on tree boles, while L. praticola and L. derjugini are
mainly ground dwelling in mesic herbaceous situations (Bannikov et
al., 1977; Darevskii, 1967; Lantz & Cyren, 1947).
L. brandtii, which may possibly be related to the L. saxicola
group, is basically ground-dwelling occurring in dry, open though

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARD
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67

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Fig. 2 Estimate of phylogeny for the Armatured clade of the Lacertidae. Adolfus, Holaspis and Gastropholis constitute the Equatorial African group.

sometimes broken situations with stones and sparse vegetation
(Lantz & Cyren, 1939; S. C. Anderson, in press).

Northwestern archaeolacertas (NW Balkan area, S Austria, Pyr-
enees and Iberian Peninsula).

L. horvathi, L. mosorensis and L. monticola are rock dwelling in

montane situations (Arnold, 1987) and the same is apparently true of

L. bonnali, L. aurelioli and L. aranica.

Algyroides (S Europe)

This small genus appears to be primarily associated with woodland
and woodland-edge habitats. In environments which have not been
radically disturbed, Algyroides are frequently encountered among
forest detritus such as fallen trunks, branches brushwood and litter.
All four species may climb to some extent both in twiggy situations
and on more continuous surfaces, including boles, branches and

_ rocks. Such climbing is much more marked in A. nigropunctatus and

A. marchi than in A. fitzingeri and A. moreoticus (Sources summa-
rised by Arnold, 1987)

| Southern ‘archaeolacertas’(N and E Mediterranean area, east to N

Iraq.
All species climb substantially although to varying extents. Climb-

_ Ing usually takes place on rocky surfaces (Arnold, 1973, 1987) but L.

laevis sometimes also occurs on tree boles (Zinner, 1967). The most
scansorial species is L. oxycephala. (Sources: Bohme, 1984; Arnold,
1987)

Lacerta parva and L. fraasii (Lebanon, E. Turkey, NW Iran,
Transcaucasus)

Both species are basically ground-dwelling occurring in dry, open

though sometimes broken situations with stones and sparse vegeta-

tion. (Wettstein, 1928; Peters, 1962; S. C. Anderson, in press; In den

Bosch, 1994)

Members of the Armatured clade

Omanosaura (E Arabia)

Both O. cyanura and O. jayakari climb on rocky surfaces, but the
latter species also spends time on open ground and occasionally even
climbs in low trees (Arnold & Gallagher, 1977; pers. obs.).

Australolacerta (South Africa)

Both A. australis and A. rupicola occur on rocky surfaces and climb
to a considerable extent (FitzSimons, 1943; De Villiers, Branch &
Baard, 1983; Branch, 1988).

Adolfus (Forest regions of east and central Africa)

A. jacksoni, A. africanus and A. vauereselli are all essentially
woodland species that often climb on fallen timber and sometimes
standing trees as well. They also forage on the ground and A.
africanus at least may climb twiggy and herbaceous plants (pers.
obs.). A. alleni is a high altitude species occurring above the tree line
in moorland situations where it lives on the ground, taking refuge in

68

dense tussocks of coarse and spiny vegetation. (Sources summarised
by Arnold, 1989b).

Holaspis (Forest regions of tropical Africa and some adjoining
savanna areas.)

The single species, H. guentheri, occurs on the trunks and branches
of standing trees, often at some height, and does not usually come to
the ground. It appears to spend much more time on steep and vertical
surfaces than any other lacertid and also often investigates narrow
crevices in wood and under bark. Holaspis is unique within its
family in being able to glide from tree to tree. (Sources summarised
by Arnold, 1989b).

Gastropholis (Forested areas of tropical Africa)

The little information available suggests the four species of this
genus are arboreal and essentially canopy forms, spending much of
their active time among twiggy vegetation. (Sources summarised by
Arnold, 1989b).

Tropidosaura (S Africa).

These are ground-dwelling species in mountain areas and are usu-
ally encountered in and around dense grassy or bushy vegetation.
Such behaviour occurs in the most basal species of the clade, 7.
montana, and may be primitive for the genus, all members of which
lack a collar beneath the throat and have large imbricate, pointed,
keeled dorsals, features usually associated with use of dense vegeta-
tion as cover (Arnold, 1973). Two of the four species, 7. gularis and
T. cottrelli, also climb on rock surfaces to a limited extent. If this is
a derived condition it is likely to have developed twice. (Sources:
Branch, 1988, pers. comm.; pers. obs.).

Poromera (Forested areas of W Africa from Gabon to Cameroun.)
Occurs on the forest floor and on fallen logs (M. Largen pers.
comm.; Freyhoff, 1994) and also climbs in grassy vegetation (Perret
and Mertens, 1957).

Nucras (E and southern Africa)

Ground dwelling especially in mesic and arid savannah often on
sandy soils. Many species are secretive and only seen after rain,
although N. tessellata is active at high temperatures. N. lalandei
occurs under stones and in long grass. (Sources: Branch, 1988, pers.
comm.; FitzSimons, 1943; Pianka, 1986).

Philochortus (NE Africa; isolated localities in and around the Sahara
desert)

Ground dwelling in dry places on sandy and stony soils often with
grass and bushes (R.H.R. Taylor, notes). Matschie (1893) recorded
P. neumanni from high grass. Philochortus possesses morphological
features that have independently evolved in the lacertid genera that
climb in grassy vegetation, Zakydromus and Poromera, and appear to
confer performance advantage in that situation; these features include,
enlarged vertebral scales with a coarse microornamentation of
anastamosing ridges, a long tail and sagittally expanded neural
spines (Arnold, 1997).

Latastia (SW Arabia, NE and E Africa, westwards through the
Sahel)

Ground dwelling in dry places with sparse vegetation (Dunger,

1967; R.H.R. Taylor, notes; J. Vindum, pers. comm.).

Heliobolus East and tropical southern Africa, Sahel etc.)

Ground dwelling in dry places. H. lugubris occurs on sparsely
vegetated compacted sandy plains and in bush veldt (Branch, 1988;
FitzSimons, 1943; R.H.R. Taylor, notes).

Ichnotropis (Tropical southern Africa)
Ground dwelling in arid and mesic savannah often with sandy soil
(Branch, 1988; FitzSimons, 1943).

E.N. ARNOLD

Pseuderemias (NE Africa)
On dry ground ranging from firm, rocky substrata to dunes (Gans &
Laurent, 1965; R.H.R Taylor, notes).

Meroles (SW Africa)

The evolution of this arid ground-dwelling clade is discussed else-
where (Arnold, 1990, 1991) and habitat differences between the
species summarised (Arnold, 1995). Most species occur on sandy
substrata but a succession of shifts to increasingly extreme environ-
ments occur along the main lineage of the phylogeny. The sequence
is: relatively firm surfaces (M. knoxii and M. suborbitalis), vegetated
hummocks separated by open areas of soft sand (M. reticulatus),
areas of looser sand and more open vegetation (the subgenus Saurites,
consisting of M. ctenodactylus, M. micropholidota and M.
cuneirostris), bare slip faces of dunes (M. anchietae). Overall the
trend is towards softer substrata and more open situations.

Pedioplanis (S Africa and Namibia)

Ground dwelling in dry usually open areas on firm substrata such as
flat and sloping rocky areas, gravel, hard soils, sandy plains and
grassy hillsides (FitzSimons, 1943, Branch, 1988).

Eremias (Palaearctic Asia and adjoining regions)

Ground dwelling in dry situations and habitats occupied by mem-
bers of the genus include firm soil, firm sand, loess and aeolian sand;
the latter habitat may have been entered twice (S. C. Anderson, in
press; Minton, 1966; Shcherbak, 1974; Smith, 1935).

Acanthodactylus (N Africa, Middle east to NW India)

Ground dwelling in open dry situations, usually on light soils or
sand. Within this general environment, there is considerable varia-
tion in microhabitat among species. Many relatively primitive forms
usually occur on fairly firm substrata with at least scattered vegeta-
tion and the A. pardalis group 1s found on loess soils. Perhaps three
lineages appear to have shifted into aeolian sand habitats, although
they may sometimes have partially reverted to firmer ground: 1. A.
grandis of Syria, Iraq and adjoining regions; 2. the A. scutellatus
clade of North Africa and northern Arabia of which A. longipes is
found in the softest most open situations (Perez Mellado, 1992; S.
Baha el Din, pers. comm.); 3. a clade ranging from Arabia to NW
India consisting of A. cantoris and its immediate relatives, among
which A. haasi 1s distinctive in often climbing in bushes. (Sources:
S. C. Anderson, in press; Arnold, 1983, 1984, 1986a; Dunger, 1967;
Ross, 1989, Mellado & Olmedo, 1991; Perez Mellado, 1992)

Mesalina (N Africa, Arabia, Middle East to NW India)
Ground dwelling in dry, open situations on firm substrata. Most
species tend to occur on compact often sandy soils but members of
the clade containing M. guttulata and M. watsonana are often found
in gravelly, stony or rocky situations. (S. C. Anderson, in press;
Arnold, 1984; Minton, 1966; Perez Mellado, 1992: Ross, 1989).
Mesalina ercolinii (Lanza and Poggesi, 1975) is only known from
a single specimen collected in central Somalia. It was initially
assigned to Eremias but is probably part of the Mesalina clade
(Arnold, Lanza et al., in press). The sole individual was collected in
a savannah habitat but there are no direct observations on its life
mode.

Ophisops (Coastal regions of N Africa; Turkey and Middle east to
India and Sri Lanka)

Ground-dwelling, usually in generally dry situations often on sandy

soils which may bear grass or patches of dense vegetation. (S. C.

Anderson, in press; Minton, 1966; Schatti & Gasperetti, 1994;

Smith, 1935). In Sri Lanka, O. leshchenaultii occurs in more open

dune areas (T. B. Karunaratne, pers. comm.).

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

Evolutionary change in structural niche

Because of the range of habitats occupied by lacertids and the wide
variation in degree of climbing they exhibit, it is very difficult to
assign species to a simple set of well defined structural niche states.
However there are a number of broad categories that can be recog-
nised, even though there is considerable variation within these and
some species may be assignable to more than one.

G_— Ground dwelling in open areas.

V — Ground dwelling and spending considerable time in situations
where movement may be restricted, such as dense grassy or twiggy
vegetation and the analogous interstices of scree etc.

M -— Climbing regularly in vegetation where the lizard tends to
progress through or over a matrix of twigs, leaves or grass.

C — Climbing regularly on more or less continuous largely open
surfaces, such as rock faces and tree boles.

The immediate outgroup of the Lacertidae, the Teiioidea, is
almost entirely ground dwelling and this appears to be the primitive
situation for the next most closely related outgroups, the
Scincomorpha and the Anguimorpha. However, while this suggests
the earliest lacertids may have been ground dwelling too, this is not
necessarily so for the immediate ancestor of surviving species.

Unfortunately, the overall history of structural niche within the
family is difficult to assess because basal relationships within the
primitive Palaearctic assemblage are not fully resolved. However
many of the component taxonomic units of this assemblage include
species that climb to some extent and often, taking these units on
their own and considering all evidence, it is more parsimonious to
regard some degree of climbing as the primitive situation relative to
a more ground-dwelling life mode. This is true for instance in
Takydromus, Podarcis and its relatives and the Gallotia-
Psammodromus clade.

Whether it is assumed ground dwelling or climbing is primitive
for the surviving members of the family, numerous transitions
between different kinds of structural habitats have to be postulated.
Even within Jakydromus there may have been a shift from climbing
to a more ground dwelling way of life and then two independent
shifts back to climbing (p. 66).

When some degree of climbing versus ground-dwelling is plotted
on the general pattern of relationships assumed here for the primitive
Palaearctic assemblage, it is more parsimonious to assume some
degree of climbing as the initial state, with multiple shift to life
mainly on the ground, either in and around dense vegetation or in
more open situations. However, this assumption is not very robust,
as assuming a ground-dwelling ancestry in ZJakydromus rather than
a climbing one makes the ancestral condition uncertain.

If a partially climbing ancestry is accepted, there must have been,
within the primitive Palaearctic assemblage, shifts to more special-
ised climbing on continuous surfaces (C) in such forms as Lacerta
oxycephala and L. perspicillata, and to specialised climbing in
vegetation matrices (M) in TJakydromus. L. vivipara would have
become ground-dwelling in dense vegetation (V) and this would
have occurred separately in L. derjugini and L. praticola within the
L. saxicola group. The L. parva-L. fraasii clade and L. brandtii
would have separately entered more open ground situations (G), and
the Psammodromus hispanicus clade occupied often intermediate
habitats (G and V).

The history of alteration of structural niche is clearer in the
Armatured clade where phylogenetic structure is more apparent.
Here, some climbing on continuous surfaces appears to have been
the primitive situation. In the Equatorial African group there was one
shift to specialised open surface climbing (C) in Holaspis, one to
matrix climbing (M) in canopy in Gastropholis and one to using

69

ground vegetation (V) in Adolfus alleni. In the main lineage of the
Armatured clade, parsimony supports a shift to more extensive
ground dwelling in the ancestor of the clade made up of Tropidosaura
and its advanced relatives with subsequent shift to more open
habitats. At the base of this clade there would have been partial shifts
to other modes: a reversion to a small degree of climbing in two
species of Tropidosaura, and to making some use of vegetable
matrixes in Poromera and perhaps Philochortus. Alternatively,
Tropidosaura, and Nucras and its advanced relatives may have
become ground-dwelling independently.

Overall there may have been a minimum of nine shifts to ground
dwelling although only about three were into really open situations
(G), five to climbing in vegetable matrixes and others to specialised
climbing on continuous surfaces. Among members of the Armatured
clade, there were multiple shifts on to soft sandy substrata: at least
one each in Pseuderemias, Meroles and Eremias and perhaps three
in Acanthodactylus.

Reversals in structural niche within the Lacertidae are less obvi-
ous, although morphology suggests this may have happened in
Takydromus, Acanthodactylus and Meroles.

MORPHOLOGY

Body proportions and vertebral number

Bodies of lacertids vary in their proportions, especially in the extent
of elongation, and change in number of presacral vertebrae is often
associated with this. The number shows some individual variation in
most species and females usually have more presacral vertebrae than
males (often about one on average but sometimes two). Typically
there are eight nuchal vertebrae and five sternal vertebrae with ribs
attached to the sternum, but the number of more posterior presacral
vertebrae varies considerably. There may be as few as ten in some
Pseuderemias and Acanthodactylus and as many as twenty in some
female Nucras lalandei, making the total presacral range for the
family 23 to 33 vertebrae.

Fairly elevated presacral counts also occur in Lacerta agilis,
Lacerta parva and L. fraasii, some members of the L. saxicola
group, L. andreanszkyi, L. graeca, Adolfus alleni and Gastropholis
(Arnold, 1973, 1989b). Females of these forms often have a total of
29 presacral vertebrae while Gastropholis frequently possesses 30.
Relatively low presacral counts of 24 to 26 in females are usual in the
more derived members of the Armatured clade including Philo-
chortus and its sister group; they also occur sporadically elsewhere.

Presacral vertebral count shows some correlation with habitat.
Forms where it is high include those that spend time in dense
vegetation, such as Lacerta agilis, Adolfus alleni, Gastropholis, and
Nucras lalandei while numbers are particularly low in species
regularly occurring in open situations. This may be related to the
amount of body flexibility necessary to negotiate habitats where
possible paths are often tortuous and ones which are unimpeded. L.
andreanszkyi which may spend considerable time in the interstices
of scree also has high counts. However any association between
vertebral number and the functional demands of habitat is imprecise,
as high counts also occur in forms that often live in open rocky
situations, such as Lacerta graeca and members of the L. saxicola
group.

Sexual variation in presacral vertebral count is absent in Gallotia,
and independently lost three times in Acanthodactylus: in A.
bedriagai, in A. schmidti populations in the United Arab Emirates,
and in the A. scutellatus group. All these cases appear to involve
reduction in female presacral number, except A. bedriagai where

70

there may have been an increase in male counts. In several ground
dwellers in dense vegetation, females have on average two more
presacral vertebrae than males. Included here are the Psammodromus
hispanicus group, Lacerta agilis, L. derjugini, L. praticola? and
Adolfus alleni. Number of abdominal vertebrae appears also to be
influenced by relative clutch mass (Bauwens, Barbadillo & Gonzalez,
1997).

Relative tail length

Because caudal autotomy and partial regeneration are frequent,
adequate data on the relative length of intact tails in adultlacertids are
not easy to collect. In most adult lacertids, intact tails vary in length
from about 1.7 to about 2.7 times the length of the head and body.
However, they are often over three times as long in many Takydromus,
Psammodromus algirus, Gastropholis, Philochortus neumanni and
P. hardeggeri, Latastia longicaudata, Pseuderemias mucronata and
P. striata. The longest tails occur in Takydromus sauteri, where they

E.N. ARNOLD

may be four times as long as the head and body, and in some T.
sexlineatus, where the tail is five times as long. Tails are particularly
short, being around 1.4 to 1.6 times the head plus body length, in
Holaspis, Eremias argus, E. przewalskii, E. quadrifrons, Acantho-
dactylus tristrami, A. robustus and Mesalina rubropunctata. In
Meroles anchietae and Eremias arguta the figure falls to about 1.
Very long and very short tails are both derived conditions within
the Lacertidae that have arisen several times. Very long tails are
frequent in forms that climb in vegetation matrixes, such as
Takydromus, Gastropholis, Psammodromus algirus and perhaps the
species of Philochortus mentioned. In at least the first two genera,
the tail is used to maintain position among stems and twigs (Arnold,
1989b, 1997) and, in general, appears to spread weight in flimsy
vegetation. This occurs in some Takydromus, such as T. sexlineatus,
when they run across the top of high grass, a situation where the tail
may perhaps also contribute thrust through lateral sinusoidal mo-
tion. In the two main clades of Takydromus (Arnold, 1997) there are

Fig. 3 Limb proportions of lacertid lizards based on data in Table 1; sexes pooled. Vertical axis: FL/HL — Forelimb span/hindlimb span. Horizontal axis:
HL/SV — Hindlimb span/snout-vent distance @ — More primitive ground dwellers; O — Ground dwellers of the clade consisting of Philochortus and its
sister group; e — forms that regularly climb to some extent. Ground dwellers using dense vegetation (upper box), also included is Lacerta andreanszkyi
which often occurs in the interstices of scree: A. Nucras lalandei, B. Lacerta vivipara, C. Lacerta andreanszkyi, D. Tropidosaura montana, E. Adolfus
alleni, F. Lacerta agilis, G. Mesalina ercolinii and H. Takydromus amurensis. Ground dwelling forms of generally open situations (lower box): K.
Psammodromus hispanicus, L. Eremias persica, M. Ichnotropis capensis, N. Philochortus intermedius, P. Latastia longicaudata, Q. Ophisops schluetert,
R. Pedioplanis lineoocellata, S. Acanthodactylus schmidti, T Acanthodactylus scutellatus, U. Heliobolus lugubris, V. Meroles reticulatus, W. Meroles
ctenodactylus, X. Meroles anchietae, Y. Pseuderemias mucronata, Z. Mesalina balfouri. Ground dwellers that probably fall between the above two
situations: I. Nucras boulengeri, J. Mesalina species A, SW Arabia (Arnold, 1986b). Forms known to climb on continuous surfaces and in vegetation
matrixes; overall, q—u appear to climb least: a. Holaspis guentheri, b. Takydromus septentrionalis, c. Gastropholis vittata, d. Gastropholis echinata, e.
Lacerta perspicillata, f. Lacerta pater, g. Lacerta oxycephala, h. Lacerta mosorensis, i. Lacerta jayakari, j. Algyroides nigropunctatus, k. Lacerta
bedriagae, |. Poromera fordi, m. Podarcis hispanica, n. Podarcis muralis, p. Lacerta viridis, q. Podarcis melisellensis, r. Podarcis sicula, s. Lacerta

laevis, t. Podarcis peloponnesiaca, u. Lacerta trilineata, y. Psammodromus algirus.

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

independent shifts to increased climbing in vegetation and this is
associated with greater tail length.

Apart from locomotory considerations, tail length in lacertids
may be influenced by different patterns of predation associated with
particular kinds of habitat. It has been suggested that long tails are
more likely to be effective in deflecting the attack of ambushing
predators and so would be expected in lizards that often hunt actively
in complex spatial habitats where such predators might hide; in
contrast it is predicted that more passively hunting lizards in open
situations would have short tails. Some indications of such an
association has been suggested for Southern African desert lacertids
(Huey & Pianka, 1981) and, taking the family as a whole, nearly all
species with very short tails are ground-dwellers in open situations.
The only exception is the aberrant tree-dwelling and gliding Holaspis.

The pattern of tail growth varies in lacertids. Relative tail length
often increases with body size, for instance in L. dugesii, L. vivipara
and L. jayakari, but decreases in Acanthodactylus scutellatus. In
Lacerta lepida relative tail length rises steeply at first but sub-
sequently levels out and eventually tends to fall and a similar growth
pattern appears to be present in L. trilineata

Limb proportions and structural niche

Limbs of lacertids are often measured individually (see for instance
Darevskii, 1967), but in intact animals it is difficult to determine a
reliable reference point for the base of the limb which is situated in
soft tissue. Because of this it is easiest to measure the total span of a
pair of limbs when fully outstretched, from the tip of the longest digit
on one side to that on the other. Fore and hind limb spans can then be
compared with each other and with the total length of the head and
body measured from the tip of the snout to the vent. The latter is of
course not an absolute criterion for comparison. As already noted,
presacral vertebral number varies between species and sexes, and
this is also true of the size of the head relative to the body; both these
factors affect body length.

Estimates of hind leg span in terms of head and body length, and
the ratio of foreleg and hind leg spans, are given for a wide variety of
lacertids in Table | and the relative distribution of selected species in
terms of these parameters is shown in Fig. 3. In the latter, the species
all fall in a restricted area of the diagram. Not only do no forms exist
where the forelimbs are longer than the hindlimbs but there is a
broad correlation between hindlimb length and the relative length of
the forelimbs: in cases where hindlimbs are comparatively short,
forelimbs tend to approach them in length, but where hindlimb span
is large, forelimb span is relatively much smaller. It follows from this
that the overall range of hindlimb span in terms of body length is
much greater than that of the forelimbs: for the former, the highest
ratio is about 2.8 times the lowest compared with less than 1.5 times
for the latter.

The kind of structural habitats species occupy correlates quite
clearly with limb proportions. Ground dwelling forms that often
occur in dense vegetation or litter have short, subequal limbs and this

_ is true of Lacerta andreanszkyi which appears to often spend time in

the confining interstices of scree. Climbing forms are similar in
proportion of the limb pairs although their legs are usually rather
longer and this pattern is found both in climbers on open surfaces
such as Holaspis and in forms from vegetation matrixes such as
Gastropholis and Takydromus. Limbs are longer still in climbing
forms that also utilise less steep surfaces quite extensively, such as
Lacerta oxycephala. Forms which climb considerably but also run in
more or less horizontal situations have even longer and less equal
limb pairs. Species that scarcely climb and occupy open ground
habitats all have very long hind legs and short front ones. This is best

71

Table 1 Limb proportions of lacertid lizards. HL/SV — Hindlimb span/
snout—vent distance; FL/HL — Forelimb span/hindlimb span; m — male, f

— female.
Species and sample size HL/SV FL/HL
Male Female Male Female
Takydromus amurensis (6m,4f) 1.02 1.03 78 Wy
Takydromus septentrionalis (11m,10f) 1.08 1.02 78 Tl
Gallotia atlantica (3m,3f) V2 ils .69 10
Gallotia g. caesaris (3m,3f) 1.34 1.26 .69 .69
Psammodromus algirus (6m,6f) 1.30 1.24 .65 64
Psammodromus hispanicus (7m, 10f) 1.30 1.23 .68 10
Lacerta vivipara (10m,10f) 0.99 0.81 82 78
Lacerta agilis bosnica (10m,10f) 1.01 0.88 .80 .80
Lacerta viridis (10m, 10f) 1.09 1.03 10 .69
Lacerta trilineata (9m,10f) 1.20 1.20 64+ .64
Lacerta lepida (5m,6f) 1.14 1.04 71 ol?)
Lacerta pater (7m,5f) 1.11 1.10 74 Jf
Lacerta andreanszkyi (1m,4f) 0.96 0.78 13) .86
Lacerta laevis (10m,10f) 1.26 NEWT .66 .67
Lacerta danfordi (7m,5f) 1.27 1.16 .67 .68
Lacerta bedriagae (8m, 13f) 1.23 1.16 Al 10
Lacerta mosorensis 10m,10f) 1.17 1.1 a7 74
Lacerta oxycephala (10m,10f) 1.17 Hite) 74 We)
Algyroides nigropunctatus (10m,7f) 1.25 Hey 71 14
Lacerta perspicillata (9m,11f) 1.13 1.00 me 714
Podarcis hispanica (9m,6f) 1.18 1.05 .69 al
Podarcis m. fiumana (10m, 10f) 1.14 0.99 65 .67
Podarcis muralis (10m, 10f) 1.12 1.03 71 sl
Podarcis s. campestris 10m, 10f) 1.20 eZ .66 65
Podarcis peloponnesiaca (19m,11f) 1.20 1.09 63 64
Lacerta jayakari (7m,9f) 1.20 1.18 AS) fl?)
Adolfus alleni (9m,7f) 0.94 0.87 alll 78
Holaspis guentheri (3m,4f) 1.01 1.01 85 .80
Gastropholis echinata (4m) 1.05 SL)
Gastropholis tropidopholis (1f) 1.16 74
Gastropholis vittata (1m,1f) 1.01 0.94 76 78
Gastropholis prasina (1m) 1.04 HT
Tropidosaura montana (3m) 0.88 8
Tropidosaura gularis (1m,1f) Weil) 0.97 52 Hil
Tropidosaura essexi (2m) 1.05 71
Tropidosaura cottrelli (1m) 1.06 aT,
Poromera fordi (3m,3f) eh) 1.28 aS) 74
Nucras boulengeri (7m,7f) 1.03 1.01 wie. 71
Nucras lalandei (4m,1f) 0.82 0.67 , Al)
Philochortus intermedius (S5m,4f) 1.34 1.16 .60 .66
Latastia longicaudata (10m,6f) 1.29 1.18 61 .63
Heliobolus lugubris (7m,4f) 1.58 Neo 13} 8)
Ichnotropis capensis (9m,5f) 1.38 1.29 64 .65
Pseuderemias mucronata (12m,6f) 1.81 1.68 il 5)
Meroles reticulatus (1m,4f) 1.73 1.58 .60 il

Meroles ctenodactylus (3m,1f) Ned Ey .60 58

Meroles cuneirostris (1f) 1.61 Si
Meroles anchietae (2m,1f) 1.74 1.66 .62 .62
Pedioplanis lineoocellata (4m,4f) 1.49 1.46 64 64
Eremias persica (3m,5f) 1.38 IES .68 .69
Acanthodactylus schmidti (12m,10f) 1.37 1.38 58 58
Acanthodactylus scutellatus (10m,3f) 1.42 1.41 58 oy)
Mesalina balfouri (6m,4f) 1.34 1.22 63 .64
Mesalina ‘A’, SW Arabia (2m,4f) 1.20 1.04 69 2
Mesalina ercolini (1f) 0.96 AY
Ophisops e. schlueteri (5m,6f) 1.51 3 .62 61

developed in Latastia and its sister group in the Armatured clade and
reaches its extreme in forms like Heliobolus lugubris, Pseuderemias
mucronata and the most derived species of Meroles. Among the
species investigated here, advanced armatured ground dwellers are
approached most closely in limb proportion within the primitive
Palaearctic assemblage by Psammodromus, the species of Podarcis
that climb least, and by Lacerta trilineata.

Because of their correlation with spatial niche, limb proportions

TZ

can be used to generate hypotheses about the habitats and locomo-
tory modes of species where these are uninvestigated or incompletely
so. Thus the one known specimen of Mesalina ercolinii occurs in the
area of Fig. 3 mainly occupied by ground dwelling forms using
dense vegetation, an exceptional habitat for an advanced armatured
lacertid. The African Poromera fordi has many morphological re-
semblances to the east Asian grass lizards, Takydromus, that seem to
be related to climbing in vegetation (Arnold, 1997) but, although the
limb pairs of Poromera are not very disparate in length, as expected
in a climber, they are distinctly longer than in Zakydromus and other
scansorial species. This suggests a locomotory difference between
the two genera and perhaps indicates that, although Poromera does
climb in vegetation, it is also frequently active in open situations, for
instance it may run on the ground more extensively than Zakydromus.

Sexual dimorphism in limb length

It will be seen from Table 1 that there is sexual variation in relative
length of the hindlimbs, which nearly always appear to be shorter in
females. In most cases the apparent difference is slight, but in a
number of taxa, it is substantial, the mean adult male hindlimb span
in terms of body length sometimes being as much as 12% more than
that of females. Marked sexual difference occurs in, among others,
Psammodromus hispanicus, Lacerta agilis, L. lepida, L. andreansz-
kyi, L. laevis, L. danfordi, Algyroides nigropunctatus, Lacerta
perspicillata, Adolfus alleni, Podarcis, Philochortus intermedius,
Latastia longicaudata, Pseuderemias mucronata, Mesalina and
Ophisops. In many cases, reduced hind limb span in females is
associated with raised forelimb/hindlimb ratio, so sexual differences

0.6

0.5

0.8 1.0 1.2

E.N. ARNOLD

within species follow the general trend among species (Fig. 4).
There appear however to be exceptions to this regularity, for instance
in Lacerta vivipara.

The sporadic distribution of marked sexual difference in limb
length indicates that it has arisen a number of times. There are also
phylogenetic indications that sexual dimorphism may have often
developed by change in limb proportions of the females rather than
the males.

The clear relationship among species between limb proportions
and the kind of spatial niche occupied suggests that intraspecific
sexual differences in limb length may reflect differences between
the sexes in microhabitat, although these do not seem to have been
systematically looked for. In some cases limb dimorphism is often
associated with differences in dorsal colouring and pattern that may
possibly be related to the problems of camouflage in different
environmental situations. Thus, in Podarcis, females not only have
shorter hind legs but are more obviously longitudinally striped than
males, a pattern that may be more cryptic in more vegetated situa-
tions.

Many forms with sexual dimorphism in limb length also show
dimorphism in head size which is probably associated with male
combat for territory and females, large heads presumably conferring
advantage in this situation. It might be thought that large limbs
would also be beneficial in this context, but the relationship between
head and limb size is not precise and some forms where the males
have large heads show little apparent limb difference between the
sexes, for instance Lacerta viridis and L. trilineata. The fact that
sexual dimorphism in limb proportions may be produced by devia

1.4 1.6

Fig. 4 Sexual differences in limb proportions in selected dimorphic species. Vertical axis: FL/HL — Forelimb span/hindlimb span. Horizontal axis: HL/SV
— Hindlimb span/snout—vent distance. Lines join means for the two sexes, females are always to the left. Letters refer to species as indicated in the
caption of Fig. 3. Sexual differences in hindlimb length are often large, compared with mean species differences; females often have more equal limb

pairs than males.

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

tion to shorter limbs in females rather than increase in limb size in
males also militates against this explanation.

It might be thought that the relatively low hindlimb/snout-vent
ratios of many female lacertids is a result of their usually higher
average number of presacral vertebrae than males (Arnold, 1973,
1989a), something that tends to produce a proportionally longer
body. However, while this may be a partial cause of low ratios, it is
not a total explanation. In Gallotia atlantica and G. galloti caesaris,
for instance, where virtually all individuals have 26 presacral verte-
brae without sexual difference, females still have relatively shorter
hind legs.

Relative proportions of femur and tibia

Measurements of the femur and tibia on dry skeletons and cleared
and stained preparations of single individuals of a wide range of
lacertid species show considerable variation. The approximate ratio
of tibia length to femur length is generally low in members of the
primitive Palaearctic assemblage and more basal members of the
Armatured clade where it ranges from about 0.73—0.87. The ratio is
particularly low, about 0.73—0.77, in such climbing forms as Lacerta
oxycephala, L. bedriagae, L. horvathi, L. perspicillata, L. mosorensis
and Holaspis guentheri.

Generally rather higher ratios, 0.76—-0.87 occur in Takydromus
septentrionalis, Lacerta agilis, L. vivipara, Psammodromus algirus,
Lacerta schreiberi, L. pater, L. chlorogaster, L. monticola, L. dugesii,
Podarcis bocagei, P. muralis, P. sicula, Adolfus jacksoni and Poromera
fordi.

Ratios are higher still, 0.88—1.00, in Psammodromus hispanicus,
Lacerta trilineata, Adolfus alleni and the clade containing more
advanced members of the Armatured group, namely Nucras and its
sister group, most of which are largely or entirely ground dwelling
in open places. Included here are Poromera fordi, Nucras boul-
engeri, N. lalandei, Philochortus spinalis, Latastia longicaudata,
Heliobolus lugubris, Ichnotropis squamulosa, Pseuderemias bren-
neri, Meroles knoxii, M. ctenodactylus, Eremias arguta, Acantho-
dactylus erythrurus, A. boskianus, Mesalina rubropunctata,
Ophisops elegans.

Patterns of limb growth

Like patterns of tail growth, the way in which the length of hind
limbs relative to that of the head and body changes during growth
from hatching to maturity is extremely varied. In such forms as
Takydromus septentrionalis and Lacerta oxycephala the hindlimbs
retain much the same relative size, while in Acanthodactylus
scutellatus andA. schmidti they show distinct reduction, for instance
growing only 90% as fast as the head and body length in A. schmidti.
In Podarcis hispanica and P. peloponnesiaca, the relative length of
the hindlimbs is retained in males but falls substantially in females.
Lacerta bedriagae, L. laevis, L. danfordi and L. perspicillata appear
to show some decline in relative rate of limb growth in both sexes,
perhaps after a slight initial rise, but the decline is more marked in
females. In cases where relative limb length changes with body size,
it is important to compare males and females of similar head and
body length when assessing sexual differences in limb proportions.

Evolutionary plasticity of limb proportions

It will be seen from Table | that hindlimb span often varies substan-
tially among closely related species, for instance within the genus
Mesalina and within the Lacerta agilis group (L. agilis, L. trilineata,
L. viridis etc.). This is also sometimes true of forms successively
derived from a lineage, such as the genera of the Armatured clade.
Such variation suggests that hind limb proportions relative to the
body length are quite plastic in evolutionary time, something cor-

qs

roborated by the varying amount of sexual dimorphism and the very
different growth patterns encountered. Lineage effects (Arnold,
1994b) in the form of phylogenetic, and specifically developmental,
constraint, consequently do not seem to be important in restricting
change in relative hind-limb length.

Although there is a clear tendency among species and sexes for
increase in relative hind-limb length to be associated with increased
difference between fore and hindlimbs, this is also unlikely to
represent a strong developmental constraint as the scatter of points in
Fig. 3 around the general trend is very substantial. Forms like
Poromera and Psammodromus algirus have similar relative hind
limb lengths but differ substantially in forelimb/hindlimb ratios.
Conversely Latastia longicaudata and Meroles anchietae possess a
similar forelimb/hindlimb ratio but differ greatly in relative hind
limb length. Again, although differences between sexes often follow
the general trend between species, there are cases where this is not
so.

It is noteworthy that the primitive Palaearctic assemblage and
more primitive members of the Armatured clade have quite short
legs but, given the general plasticity of limb proportions, this seems
unlikely to represent a developmental constraint and may simply
reflect the habitats they usually occupy. The limb proportions of
Psammodromus algirus, which belongs to the primitive Palaearctic
assemblage but often runs on the ground in open areas, as well as
climbing, approach those of advanced armatured forms that are
nearly all found in such situations.

Functional aspects of differences in limb proportions

Given the plasticity of limb proportions in lacertid lizards and their
correlation with kinds of habitats occupied, it would not be surpris-
ing if differences between species reflected the functional
problems of locomotion in particular environments and were pro-
duced by natural selection. A more detailed case for this is given in
the rest of this paper but likely advantages of different limb propor-
tions are briefly summarised here. Ground dwelling forms from
open habitats get most of their forward thrust when running from
the hind limbs. Such thrust is enhanced by greater general hind-
limb length relative to the forelimbs, and an extended crus reflected
in increased tibial length relative to the femur. The openness of the
habitat allows such long hind limbs to be used effectively and
probable increase in mass of the caudifemoralis longus muscle
increases the power of what is a high-gear system of locomotion
that delivers the high speeds necessary to evade predators in situ-
ations where cover is sparse.

In contrast, ground dwelling forms that spend considerable time
in dense vegetation benefit from generally short limbs which can be
deployed in the restricted spaces available. Speeds are lower but
concealment from predators is easier. Possibly the greater relative
length of the forelimbs reflects greater use in locomotion. Thrust
from the small hindlimbs may not be optimal for locomotion and the
flexibility of an often relatively long body may reduce its effective
transmission. In these circumstances some traction by the forelimbs
may be advantageous.

Climbers in vegetation matrixes have similar proportions to those
just discussed and are likely to encounter similar locomotory prob-
lems. Another factor favouring short limbs in climbers in general is
that they give low gearing which is likely to be beneficial when
moving upwards against the force of gravity. The relatively long
forelimbs in these forms may also allow them to contribute effec-
tively to upward locomotion and they are also important in securing
the foreparts, which are above the centre of gravity of the lizard as a
whole during vertical climbing and so liable to fall away from the
surface being climbed if unattached.

74
Differences in the caudifemoralis longus muscle

The caudifemoralis longus is the main muscle retracting the femur in
lizards and runs from the femoral trochanter posteriorly on to the
proximal caudal vertebrae to which it attaches by multiple heads
(see e.g. Russell & Bauer, 1992; Arnold, 1994a). The muscle is
roughly triangular in shape and its tapering posterior section extends
backwards to caudal vertebra 6—13 in lacertids, usually reaching
beyond the first autotomy plane discernable in radiographs. The
number of autotomic vertebrae to which the caudifemoralis attaches
ranges from one to six (L. Hartley, E. N. Arnold, pers. obs). The fact
that the muscle extends beyond the first autotomy plane means that
some of the most posterior part of the muscle may be lost as a result
of caudal autotomy if breakage occurs far proximally, a not uncom-
mon event in some species, for instance Lacerta vivipara (Barbadillo
et al., 1995). However the effect of such loss on limb function may
be relatively small, for the bulk of the muscle lies anterior to the first
autotomy plane and the fact that there are attachments to a number
of nonautotomic vertebrae means that loss of the posterior section
will not result in general loss of function.

There is a phylogenetic regularity in the position of the first caudal
autotomy plane discernible in radiographs. In more basal lacertids
this is usually on the fourth to seventh caudal vertebra but in most
Nucras and in its advanced sister group there is a posterior shift and
the first plane is usually no further forwards than the eighth vertebra.
This shift may mean that the bulk of the caudifemoralis longus is

~<«— head 4 ———<$$$$=——

forward
rotation
FEMUR
mesial lateral
protraction a retraction
abduction adduction
—_—— SP
CRUS
METATARSAL
SEGMENT

DIGITS

Fig.5 Skeleton of left hind limb of lacertid from above, showing main
elements and regions, orientation and directions of movement.

E.N. ARNOLD

increased in these lizards and the proportion that remains after
proximal autotomy is certainly larger. The number of non-autotomic
vertebrae tends to be higher in males than females which means the
former may possess a greater bulk of muscle to retract their rela-
tively longer hind legs.

General anatomy of the hind leg (Fig. 5)

In advanced ground dwellers of the Armatured clade, the more distal
elements of the hind limb are elongated and it is possible for the leg
to be extended until it is more or less straight. The knee is essentially
a ginglymus, that is a hinge joint moving mainly in a single plane,
but does not run perpendicular to the long axis of the femur instead
being angled mesially (Rewcastle, 1980). This results in a complex
flexure of the crus on the femur in three dimensions. The mesotarsal
joint between the crus and the metatarsal segment of the limb which
runs between the astragalo-calcaneum and the other tibial bones, is
also primarily a hinge joint and the foot can be extended in line with
the crus or flexed until it is more or less parallel with it. However,
these hinge joints in the hind leg do not have movement entirely
confined to one direction. The crus can twist or swing to a small
extent relative to the femur and the foot can flex inwards relative to
the crus, some additional motion taking place at the base of the
metatarsals, The foot can also twist on the crus to some extent. The
hind limb of climbing lizards like Lacerta oxycephala is similar, but
the distal segments are less elongated and the foot is usually in-
flected mesially.

Structure of the pes

In this and following descriptions feet are assumed to be placed sole-
down on a horizontal surface. The lacertid pes exhibits essentially
the primitive lizard structure with no loss or increase of elements in
the tarsus, metatarsus or phalanges, the phalangeal formula being
2,3,4,5,4. Digits articulate with the metatarsals via ball and cup
joints that allow considerable movement in all directions; in contrast
the joints between the distal claw-bearing phalanges and the penul-
timate ones are double-headed ginglymi that are tightly bound and
only permit the claw to move in the vertical plane.

Table 2 Characteristics of the pes in ground dwelling and climbing
lacertids (see Figs 7-10).

Ground dwelling
(e.g. Acanthodactylus)

Climbing
(e.g. L. oxycephala)

Relative length of
metatarsal bones

4 longer than 3 3 longer than 4

Digits 14 long shorter
Relative length of meta- 4 markedly 4 not much
tarsal + digits 3 and 4 longer than 3 longer than 3
Size of digit 5 short, often long
minaturised

Shape of digits 3-5
in lateral view

gently curved ventrally clearly kinked
or straight

Cross section rounded latero-mesially
of digits compressed

Shape of phalanges robust more slender

Prepenultimate phalanx of no yes

digits 24 markedly shorter
than contiguous ones

Claw long and shallow short and deep

Articulations double-headed simple
within digits
Mesial flexibility restricted substantial

of digits 14

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

Ss

Fig. 6 Lateral view of the bones of the distal part of the digit of a
climbing lacertid, showing dorsal and ventral tendons (black) attaching
to deep, claw-bearing distal phalanx. The sesamoid bone (s), which can
slide on the surface of the penultimate phalanx, displaces the dorsal
tendon away from the hinge-line of the articulation between the two
phalanges, increasing its moment arm around the centre of rotation and
its efficacy in raising the distal phalanx and its claw.

Fig. 7 Lateral and dorsal views of fourth hind digits. a., c. Ground-
dwelling lacertid, Lacerta agilis. b., d. Specialised climber, Lacerta
oxycephala.

75

The dorsal tendon of each digit which inserts on the final claw-
bearing phalanx encloses a small sesamoid bone that lies close to the
articulation of this phalanx with the penultimate one (Fig. 6). This
digital sesamoid acts like a more familiar one, the patella (knee cap)
of many mammals, in enhancing the efficacy of the tendon by
moving it away from the hinge-line of the articulation and increasing
its moment arm around the centre of rotation of the distal phalanx
(Curry, 1984).

There are considerable differences in proportions of the pes and in
shape and relative orientation of the phalanges and claws. The
extremes are found in strictly ground dwelling forms, especially the
more advanced members of the Armatured clade, and in those that
climb extensively on steep open continuous surfaces. Basic differ-
ences are summarised in Table 2.

The pes in ground dwelling lacertids from open situations (Figs
Ta,c, 8a, 9a, 10a ).

In advanced members of the Armatured clade, like Acanthodactylus,
the whole foot is large and metatarsal bones | to 4, and the digits
arising from these, are especially long and increase successively in
length. In some instances, such as Heliobolus lugubris the metatarsal
bones are more or less parallel and bound closely together. Digits 1—
4 are also elongated but digit 5, which arises from the highly modified
fifth metatarsal bone, is frequently short and may be miniaturised, its
phalanges and claw being much smaller than those of other toes. In
extreme cases like Heliobolus lugubris, the whole fifth toe only
extends as far as the distal end of metatarsal 4. Similar substantial
reduction also occurs in /chnotropis capensis. Toes are straight or
gently curved ventrally when at rest (Fig. 9a) and are rounded in cross
section (Fig. 10a). The phalanges themselves are robust (Fig. 9a) and
tend to become steadily shorter distally in each digit.Although the pre-
penultimate phalanx of toes 3 and 4, may sometimes be a little shorter
than contiguous ones this is not very marked. The terminal phalanx of
each digit and the claw that covers it is relatively long, shallow and
curves gently downwards. The prominence on the terminal phalanx,
to which the ventral tendon of the digit is attached, is relatively close
to the centre of rotation of the claw (Fig. 17c).

Articulations within the digits are double consisting of two hori-
zontally arranged protruberences on the distal end of each phalanx
that fit into two hollows on the proximal end of the adjoining one.
Although the articulations all appear at first sight to be ginglymi,
only the most distal one totally restricts movement to the vertical
plane. The others in digits 24 allow these toes to be flexed laterally
so they can curve quite easily in this direction, even though they are
rather stiff basally. However, mesial flexion of these digits is more
restricted and they can only form a gentle curve in this direction. The
different extents of lateral and of mesial movement within these
digits presumably depends on the degree of restriction produced by
the ligamentous connections on each side of the articulations and by
accessory tendons. Digit 5 swings easily around its base but joints
within it, while allowing some movement, are generally stiffer in the
horizontal plane than those in digits 24. All digits can be flexed
extensively downwards and upwards when the muscles controlling
them are relaxed.

Similar structure of the pes is found throughout the open-ground
forms that constitute the clade made up of Latastia and its advanced
sister group; it is also approached in many aspects in such ground-
dwelling primitive Palaearctic species as Lacerta agilis (Fig. 9a, 10a).

The pes in lacertids regularly climbing on steep open surfaces
(Figs 7b, d, 8b, 9b—-e, 10b).

In Lacerta oxycephala, a species that habitually climbs on precipi-
tous rock outcrops (Arnold, 1987), the foot is small and metatarsal

76

a

E.N. ARNOLD

b

Fig. 8 Dorsal views of right pes of lacertids (digit 1 to left). a. Ground dwelling Acanthodactylus erythrurus: metatarsal 4 longest, digit articulations
double headed, digit 5 miniaturised. b. Rock climbing Lacerta oxycephala: metatarsal 3 longest, digit articulations single, digit 5 large, phalanges
slender, intermediate ones in digits 3 and 4 relatively short. For other differences, see Table 2.

bones 1—4, and the digits that arise from them, are quite short. The
metatarsals and digits exhibit an increase in length from number | to
3 but metatarsal 4 is shorter than metatarsal 3 and, although digits 1—
4 increase in length, the shortness of metatarsal 4 results in digit 4
projecting only a comparatively short distance beyond digit 3. Digit
5 is relatively long and unminiaturised, the articulation of its second
and third phalanges being about level with the distal end of metatar-
sal 4. When at rest, digits 3-5 are distinctly kinked in the sagittal
plane with abrupt changes of direction along their length (Fig. 9b—
d). In digit 3, phalanx 2 is directed downwards, 3 upwards and 4
downwards. In digit 4, phalanx 2 is directed downwards, 3 ap-
proaches the horizontal, 4 is flexed upwards and-5 downwards. In
digit 5, phalanx 2 is directed upwards, 3 is roughly horizontal and 4
flexed downwards, but there is sometimes marked deviation from
this pattern (see p. 77). Kinking when digits are at rest appears to be
maintained partly by the form of the envelope of skin that surrounds
each digit and that of the ligamentous connexions that surround each
interphalangeal joint. If the digit of a live lizard is stretched by

pulling the claw, kinking disappears temporarily, but it is transiently
increased if the tension in the tendons lying dorsal and ventral to the
phalanges is raised by the action of the muscles that activate them.
Kinking is often especially marked in animals preserved in alcohol
or formalin because shrinkage of muscle tissue produces similar
tension in the tendons.

The digits are mesiolaterally compressed when transversely sec-
tioned through a phalanx (Fig. 10b), instead of having a more
rounded profile like ground dwellers. This difference results from
the relative thicknesses of the phalanges and the surrounding ten-
dons, especially the ventral ones. In ground dwellers the latter may
be considerably more slender than the robust phalanges above them,
while in climbers like Lacerta oxycephala, where the phalanges are
more delicate in build, the stout ventral tendons may be as thick as
thicker than these. The penultimate phalanx of each digit is long and
gently curved downwards while phalanx 2 in digit 3 and phalanges
2 and 3 in digit 4 are shorter than those proximal and distal to them.
The terminal phalanx of each digit and the claw that covers it is short,

_ NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

— =
oe. see
ae Beer fr

Fig. 9 Digits of pes of lacertids in lateral view. a. Ground dweller,
Lacerta agilis, digit 4. b—d. Climbing species, Lacerta oxycephala,
digits 3, 4 and 5. e. Climbing species, Lacerta perspicillata showing
alternative pattern of flexion in digit 5.

deep and strongly recurved. The prominence on the terminal pha-
lanx, to which the ventral tendon of the digit is attached, is situated
well away from the centre of rotation of the claw, conferring
considerable mechanical advantage (Fig. 17b). The tendon stands
well away from the articulation when the claw is ventriflected; it also
_ tends to do the same under the downflexed joint between phalanges
1 and 2 in digits 3 and 4 (Fig. 17b), and 2 and 3 in digit 5.

Articulations within the digit except for the most distal one are
simple, consisting of a single protruberance at the distal end of each
phalanx that fits into a cup on the adjoining one. These confer
| substantial mobility in both the vertical and horizontal planes. As in
ground dwellers, digits 2-4 can curve laterally and swing mesially
around their base until their proximal phalanges are in line with their
metatarsals. Unlike those of ground dwellers, the digits themselves
can bend quite abruptly in a mesial direction, as a result especially of
flexibility at their penultimate articulations but also, to some extent,
of that at the articulations between phalanges | and 2 in digits 3 and
4 and that between 2 and 3 in digit 5. Toe 5 is not only lateromesially
mobile at its base but also at other joints.

77

dorsal tendon

phalanx

ventral tendon

Fig. 10 Diagramatic transverse sections of toe 4 of a. Lacerta agilis and
b. Lacerta oxycephala, showing differences in relative cross sectional
area of phalanx and ventral tendon.

Variations in the direction of kinking in toe 5 of lacertids

Most climbing lacertids possess a pattern of kinking in toe 5 like that
found in Lacerta oxycephala and described above (Fig. 9d, called
here pattern A). However, a minority possess a condition where
phalanx 2 is directed downwards, 3 upwards and 4 downwards (Fig.
9e, called here pattern B). Pattern B is found in Lacerta I. laevis, L.
l. troodica, many L. kulzeri, L. chlorogaster, L. dugesii and L.
perspicillata, Algyroides, and the Equatorial African group (Fig. 2)
of the Armatured clade; it occurs in weaker form in Jakydromus and
Poromera. This variant has consequently evolved perhaps seven
times and, at least in Equatorial African group, in L. chlorogaster
and probably elsewhere, seems likely to have had developed in
ancestors that exhibited pattern A. In spite of pattern B originating
on several occasions, the details of kinking in toe 5 are often stable
across quite large and varied clades, for instance the Equatorial
African group. Interestingly, many of the lacertid taxa showing
pattern B are known to climb on vegetable structures, such as tree
boles and flimsy herbage, which might at first sight suggest that it
confers some performance advantage in these specialised situations
(but see below)

Patterns of digital kinking in climbers of other families

Many other lizards that climb habitually have kinked digits on the
pes and also often on the manus. Attention will be directed here to
forms with simple toes, without the complex adhesive pads that
occur in many geckoes and anoles. As in the digits of lacertids, the
distal part of toes consists of an upwardly directed arc which may
contain three phalanges (pattern A) or just two (pattern B).

These patterns occur in various combinations on digits 3, 4 and 5 of
the pes and a particular combination for these three toes can be
specified simply by a three letter code, for instance for lacertids this
would be most usually B.B.A but sometimes B.B.B. There is also
some variation in the orientation of the more proximal phalanges of
toes 3—5 but this will not be discussed further here. Observed patterns
in the distal parts of toes 3—5 in a range of lizards are given below.

A.A.A. Petrosaurus mearnsi (Phrynosomatidae); Plica plica#
(Tropiduridae); Gonocephalus modestus#, Draco blanfordii#
(Agamidae); Agamura persica, Cyrtodactylus consobrinus#
(Gekkonidae); Xantusia henshawi, Lepidophyma flavimaculata
(Xantusiidae); Platysaurus, Pseudocordylus (Cordylidae); Mabuya
quinquetaeniata (Scincidae).

A.B.A Tropidurus torquatus (Tropiduridae).

B.B.A Agama caudospinosa (Agamidae), most lacertids.

B.B.B. Varanus indicus#, V. mitchelli#, V. tristis# (Varanidae);
Cryptoblepharus boutoni (Scincidae); several lacertids# .

B.A.B. Cnemaspis africanus #(Gekkonidae).

78

When three toes are considered, there are eight possible combina-
tions of the two patterns of kinking. BBB* (3), BBA* (2), BAB* (1),
BAA, ABB, ABA* (1), AAB, AAA* (9). Five of these (asterisked)
have already been observed in the small sample of climbing lizards
examined; figures in parentheses indicate the number of cases
encountered of each.

As already noted, pattern B in toe 5 is most usual among lacertids
in forms that climb on vegetable structures (marked#), but when
members of other families are also considered it is clear there are
species with fifth toes exhibiting pattern A in this situation. Overall,
there is no obvious correlation of pattern B with climbing on
vegetable structures in any of toes 3-5.

The widespread occurrence of toe kinking in climbing lizards and
its repeated evolution suggests that it confers performance advan-
tage in this locomotory situation. However, the variety of patterns,
including differences in the more proximal parts of toes 3—5, and the
fact that they occur in various combinations in these toes, suggests
that the exact arrangement of phalanges may be rather arbitrary in
functional terms. Nonetheless, the existence of a particular pattern
across some clades within the Lacertidae indicates that, once a
pattern for a toe has become established, it may persist for long
periods, even though multiple shift from pattern A to pattern B in toe
5 has also occurred. If the pattern of kinking is more or less arbitrary
in functional terms, shift from one to the other might sometimes
occur after an intervening non-climbing phase when the initial
pattern was lost, but there is no overt evidence for such interludes.

The structure of the manus

As with the pes, the lacertid manus always possesses the primitive
lizard phalangeal formula, which in this case is 2,3,4,5,3. The manus
is also like the pes in the way the digits articulate with the metacarpals
via ball and cup joints and in having terminal articulations that are
tightly bound gynglymi with associated sesamoid bones. Metacar-
pal 3 is always the longest and numbers | and 5 the shortest, the
digits are more equal in length than those of the pes and are capable
of being broadly spread.

The manus in ground dwelling lacertids from open situations

(Fig. lla, Table 3)

In advanced members of the -Armatured clade, the manus is often
quite small compared with the pes although this differential is less
obvious in species from soft-sand habitats. The longest digit is
usually number 3 or this is subequal to 4. Toes are straight or gently
curved ventrally and are rounded in cross section. The phalanges are
often very robust, frequently more so than in the pes, and except for
the terminal ones, tend to be subequal within a digit. The relative
brevity of toe 4, which has most phalanges, means that these are
particularly short. The final phalanx of each digit and the claw that
covers it tends to be long, shallow and curves gently downwards.
Articulations within digits are double and, as in the pes, mesial
flexion of the toes is restricted.

The manus in lacertids regularly climbing on steep open surfaces
(Figs 11b,c, Table 3)

In forms like Lacerta oxycephala, the manus is smaller than the pes
but comparatively much larger than in many ground dwellers. The
longest digit is usually number 4 and digits are lateromesially
compressed; numbers 3 and 4 are flexed downwards at the articula-
tion of phalanges 1 and 2, and somewhat upwards at the penultimate
articulation, as in the other digits. Phalanges are slender, the penul-
timate ones being relatively long and slightly curved downwards;
phalanx number 2 of digits 3 and 4 and also number 3 of the latter are

E.N. ARNOLD

Table 3. Characteristics of the manus in ground dwelling and climbing
lacertids (see Fig. 11). Differences in transverse section of the digits, shape
of phalanges, claws and articulations within digits are similar to those in
the pes.

Ground Climbing
(e.g Acanthodactylus) (L. oxycephala)
Longest digit 3, or 3 and 4 subequal 4
Phalange 2 of digits 3 weakly strongly
and 4 and phalanx
3 of digit 4 shortened
Phalange 2 of toes 3 no yes
and 4 flexed downwards
Digits can be very no yes
very widely spread
Mesial flexibility of restricted substantial

digits

shorter than the ones bordering them. The final phalanx of each digit
and the claw that covers it is short deep and recurved. As in the pes,
the main ventral tendons are offset in the regions where digits are
flexed downwards. Articulations within the digits are simple involy-
ing a single cup and ball arrangement and the digits can be abruptly
flexed in the horizontal plane both mesially and laterally, especially
in the area of the penultimate articulation.

The manus of Holaspis guentheri (Fig. 11c) deviates consider-
ably from that characteristic of other lacertids climbing on continuous
open surfaces. Digits 2—5 are more subequal in length, and numbers
3 and 4 are conjoined for the length of their first phalanx, penult-
mate phalanges are extremely long and more curved ventrally than
in other lacertids and phalanx 2 of toe 3 and phalanges 2 and 3 of toe
4 are very short and flexed downwards. This degree of distinctive-
ness in the manus of Holaspis contrasts with that of the pes which,
although it has the features usually associated with climbing on open
surfaces better developed than in Lacerta oxycephala, does not
differ radically from this species in its general form.

Characteristics of the feet in other lacertids

The numerous primitive Palaearctic lacertids and more basal mem-
bers of the Armatured clade that climb to a significant extent on open
surfaces have at least less marked versions of the foot characters that
form a syndrome in a specialised climber like L. oxycephala,
although the foot tends to be longer. Thus, the claws are relatively
deep, the toes compressed and kinked, and metatarsal 3 is longer
than 4 in the pes. These features occur, for instance, in many
‘archaeolacertas’, some Podarcis such as P. hispanica, Algyroides
nigropunctatus and A. marchi, members of the Lacerta agilis group
but not L. agilis itself, Gallotia, Psammodromus algirus,
Australolacerta and most members of the Equatorial African group.
Independent shifts to the more marked version of the syndrome are
found in such frequent climbers as Lacerta perspicillata,
Omanosaura and especially Holaspis.

Forms that climb in vegetation matrixes, like Gastropholis, some
Takydromus and Poromera, tend to have relatively weak versions of
the climbing pattern but may also possess distinctive features for
instance, in the latter two genera, separation between the digits may
extend proximally between the distal parts of the metacarpals and
metatarsals, allowing wider spread of the digits.

The manus and pes features that characterise advanced ground-
dwelling members of the Armatured clade have developed in other
ground-dwelling lacertids, at least in restricted form. Thus metatar-
sal 4 is about equal to number 3 in Lacerta agilis, Psammodromus
hispanicus and Adolfus alleni and is longer in some Podarcis that run
extensively on the ground, such as P. sicula and P. taurica. Digit 5 of

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS 79

Cc

Fig. 11 Right manus of lacertids (digit 1 to left), a., b. dorsal, c. anterodorsal. a. Ground dwelling Acanthodactylus erythrurus: digit 3 longest, phalanges
robust. b. Rock climbing Lacerta oxycephala: digit 4 longest, phalanges slender. c. Holaspis guentheri: toe 5 long, toes 3 and 4 strongly kinked. See
Table 2 for other differences between a. and b.

80

the pes may be small in some of these forms and the digits are often
not strongly kinked and have robust subequal phalanges and rounded
cross sections. The syndrome is best developed as whole in
Psammodromus hispanicus and L. agilis.

In some cases, a mixture of features typical of ground-dwelling
and other activities occur. This may be a result of functional compro-
mises, for instance in forms that are substantially ground dwelling
but also occur in other situations. In Lacerta vivipara, a ground form
that spends substantial time in dense grassy vegetation, many features
associated with ground dwelling are present but metatarsal 4 is short
and toe 5 quite long. Possibly the way the feet of this species are used
in traversing vegetation has similarities to climbing. In Poromera,
the foot has some features associated with ground locomotion and
some with climbing quite strongly developed. However, in spite of
probably sometimes climbing in vegetation, the hands and feet of
Philochortus are essentially of the ground type.

Overall, direction of change in foot morphology appears to follow
closely that of structural niche in lacertids (p. 00).

The variations in the pes found in lacertids are paralleled quite
closely in some other families. For instance, within the sister group
of lacertids, the Teiioidea, the Tetidae which are mainly ground
dwelling in open situations have the pedal characteristics of lacertids
occupying similar structural habitats. As here, the fifth toe is usually
miniaturised and in Jeius disappears entirely, something that also
occurs in the ground running agamid Sitana (Russell and Rewcastle,
1979).

Special structures of the digits

In primitive Palaearctic lacertids and more basal members of the
Armatured clade including Nucras, the toes are covered above with
a single row of unkeeled scales along their length and below by a row
of scales or lamellae that correspond more or less to those above. The
lower row is often tubercular and each scale may be divided cen-
trally, although this feature varies considerably, sometimes even
among subdigital scales on the same toe. A number of modifications
of this primitive external toe structure occur.

Expanded subdigital lamellae

Takydromus kuehnei is unique among lacertids in having the more
proximal subdigital lamellae of the digits clearly expanded laterally
to form a narrow pad superficially similar to those of geckoes such
as Cyrtodactylus. This feature, towards which there is a slight
tendency in some other Takydromus, may possibly enhance adhe-
sion on the surfaces of the vegetation, among which these lizards are
often found, by increasing the lower surface of the toes. However,
SEM studies reveal no microornamentation of adhesive setae on the
subdigital lamellae of Takydromus kuehnei (pers. obs.), such as are
found in other pad bearing climbing forms including many geckoes
and anoles, and the skink, Prasinohaema virens (Williams & Peter-
son, 1982).

Keeling of subdigital scales
Instead of being tubercular, the scales beneath the digits of lacertids
may bear keels which, in ventral view, appear more or less parallel
to the axis of the digit. In these cases the free edge of each scale and
its keels are directed obliquely downwards, the latter ending in
projections. When a toe is put down on a smooth flat surface, contact
with this is largely limited to these points. Downwardly directed
scales with keels ending in projections also occur on the palms and
soles.

A tendency to keeling, often with considerable individual varia-
tion occurs in most Psammodromus species and in Philochortus.

E.N. ARNOLD

Fully developed and consistent keeling is found in the advanced
clade of ground dwellers in the Armatured clade that constitutes the
sister group of Philochortus. Full keeling has evolved independently
in Psammodromus hispanicus (presumably from the intermediate
condition in other members of the genus), in Omanosaura cyanura,
and in Lacerta cappadocica; there are thus four origins of the
condition within the Lacertidae.

The number of keels on subdigital lamellae varies: two is most
frequent but there are sometimes several, something which is com-
moner on the manus than the pes. Single keels also occur, in Lacerta
cappadocica and in dune dwelling species of Meroles,
Acanthodactylus and Eremias in which they are associated with less
downward projection of the edge of the scale and little development
of projections at the tips of the keels. In at least the first two genera,
the shift to single keels has happened more than once.

Keeling on subdigital scales may vary within a species, for
example there may be one to several in different populations of
Acanthodactylus grandis (Arnold, 1983). This suggests keeling is
quite labile in detailed form. Species that live exclusively on very
fine aeolian sand may lose keeling secondarily, something that has
developed independently in Meroles anchietae and Eremias
(Scapteira).

Evolutionary shift to keeling does not appear to be related to
changed locomotory requirements and instead may be more import-
ant in protecting the toes from high temperatures (Arnold, 1973).
Some desert lacertids are at least briefly active on surfaces as hot as
60°C (pers. obs.), even though their digits incorporate delicate blood
vessels and nerves. In this situation, limiting contact with the ground
largely to the projections at the end of keels is likely to reduce heat
intake, especially as keratin, of which the subdigital lamellae are
formed, is a good insulator. If this is so, keeling may not be important
as such but only as a means of providing support for the projections
that actually contact the ground. Similar support of projections by
keels is found in the belly scales of many Takydromus species,
although here the projections appear more important in increasing
frictional contact rather than in insulation (Arnold, 1997).

In the Armatured clade, the shift to keeling is associated with
movement into hot open ground habitats and the same is true in
Psammodromus. The Lacerta and Omanosaura with keeled digits
are rock-dwellers but in particularly warm areas.

It is not clear why aeolian sand species often exhibit reduction
from double or multiple to single keels with less downward inflexion
of the free edges of the subdigital scales, and sometimes totally lose
these features. One possibility is that the keeling and the associated
projections will not be able to keep the digits substantially out of
contact with the ground, because the toes of running lizards usually
sink into soft sand, at least to some extent, so projections supported
by keels will not restrict contact. In fact, the sinking may also reduce
the problem of heat load since the digits are only briefly in contact
with the very hot uppermost layer of sand and pass rapidly through
it into the rather cooler layers below.

Outside the Lacertidae, digital keeling occurs in many other lizard
families and is usually associated with hot substrata. It is found in
many iguanians, scincids and cordylids that occur in sunny situa-
tions, but is absent in largely nocturnal or mesic clades such as
gekkotans, xantusiids and anguids. The development of full keeling
is probably associated with modest body size, a situation in which
the problems of overheating of the extremities are likely to be
particularly acute.

Digital fringes
Lateral and often mesial fringes of pointed scales on the digits have
developed in at least five separate clades of the Lacertidae: in

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

Acanthodactylus, Meroles, Eremias, Holaspis and, in restricted
form, in Pseuderemias. In Acanthodactylus a lateral scale row is
present on the digits of manus and pes of all species, but an
additional mesial row has developed on the manus perhaps three or
more times in groups living mainly on soft sand (Arnold, 1983;
Harris, Arnold & Thomas, submitted b). Meroles is similar in that all
species have a lateral scale row on all digits, and a mesial row on
those of the manus in a clade found on soft sand, consisting of the
subgenus Saurites and Meroles anchietae. A mesial row occurs on
the pes as well in Meroles anchietae which is found in the most
extreme of such habitats (Arnold, 1991). Lateral and mesial scale
rows have also evolved on all feet in the aeolian sand species of
Eremias (Scapteira). Holaspis is distinctive in exhibiting additional
scale rows only on some of the digits of the pes: digits 3 and 4
possess lateral and mesial rows, while digit 5 has a lateral row which
is continuous with similar scales on the trailing edge of the hind leg
and the sides of the tail.

In sand dwelling forms, the additional scale rows on the digits,
which are often elongated and projecting, act rather like snow shoes
during locomotion, reducing the tendency of the feet to sink into the
yielding substratum (Carothers, 1986; Luke, 1986) and thus increas-
ing effective thrust when running. However, it is notable that,
although ground dwelling lizards obtain most locomotory thrust
from the hind legs (p. 000), additional mesial rows of scales develop
first on the manus. This may be because the forefeet especially are
used in digging for food and to construct burrows and in this
situation the fringes increase the efficacy of digging by broadening
the toes so they shift more sand. Possibly, where sand is not
especially soft, the functional advantage of an additional scale row is
more critical in digging than running.

Although lateral expansion of the digits appears to confer advan-
tage when running and digging in soft sand situations, it is less clear
why expansion should be achieved by separate additional scale rows
in lacertids, since some sand-dwelling lizards in other families
merely have the usual dorsal and ventral scale rows on the digits
extended horizontally to form fringes (Luke, 1986). Indeed in sand
lacertids without a mesial row, the dorsal scale row may project in
this way. Possibly, separate rows of scales on the sides of the digits
do not actually give better function, in impeding the toes when they
are pressed into the substratum, than fringes produced from dorsal
and ventral rows. They may however be advantageous in environ-
ments where sand is very soft because fringes made up of independent
scale rows can flex more easily ventrally, reducing impedence when
digits are withdrawn from the sand.

In contrast to their function in sand dwellers, the additional
digital scale rows of Holaspis probably provide extra lift when this
unique lacertid glides through the air (Arnold, 1989b). In some
iguanians such fringes permit the lizards to run across the surface
of water (Luke, 1986). Although fringes made up of additional
scale rows on the digits thus occur in three superficially quite
different situations, in all of them they slow or prevent passage of
the feet through fluids.

Not only have digital fringes in lacertids been elaborated by
subsequent addition of separate lateral scale rows, but the length
of the scales forming these also varies, often showing considerable
correlation within a genus with the softness of the substratum
usually occupied (Arnold, 1983). However, although some mem-
bers of primarily sand dwelling clades appear to have reverted to
firmer substrata, for instance Meroles suborbitalis, there are no
certain cases where additional digital scale rows have been subse-
quently lost even though their degree of projection may be
reduced.

81
LOCOMOTION AND FUNCTION

Some aspects of locomotion in habitual open ground lizards and in
climbers are contrasted in Table 4

Locomotion in ground dwellers of the Armatured
clade (Figs 12—13)

The following observations are based on Heliobolus lugubris,
Meroles cuneirostris, M. reticulatus, M. anchietae, Eremias arguta,
Acanthodactylus boskianus and A. pardalis. These were either
videoed dorsally and laterally at 25 fields/sec and an exposure of
1/1000 sec., or filmed at 16-48 frames/sec. Meroles cuneirostris was
also videoed at 200 fields/sec. Most runs were conducted on a flat
cork surface but animals were also allowed to sprint across soft sand
and the footprints produced used to to check stride length and
relative thrust of the fore and hind feet, as indicated by pressure
waves in the sand produced at the trailing edge of the prints.

Lacertid lizards use all four legs when running. The gait is
sprawling, that is the humeri and femora project from the body
roughly in the horizontal plane, and the steps of individual limbs can
be divided into two phases: the power stroke when the limb is
retracted and actually delivers thrust, and the recovery stroke when
it is is brought rapidly forwards in preparation for the next step.
Typically the fore and hind limbs work in diagonal pairs, for
instance, the right foreleg and left hindleg are brought forwards in
the recovery stroke at about the same time and are retracted more or
less together in the power stroke; there may however be a slight lag,
so that a hindlimb starts to move forwards after the contralateral
forelimb.

At extreme phases of the locomotory cycle, the forelimb on one
side of the body is directed backwards and the hindlimb forwards, so
they approach each other or overlap, while on the other side of the
body the limbs are directed diametrically away from each other. In
general, strictly ground-dwelling lizards of the Armatured clade
carry the body well away from the substratum when running. At the
end of the power stroke of a hind limb, the lizard may be balanced on
the toes of a single foot and this is followed by a gliding phase when
the animal ‘floats’ forwards with all limbs off the ground.

Because of this floating phase, the total stride of each limb pair,
that is distance between ground contact of left and right feet, may be
substantially greater than the anatomical stride which is the distance
between the feet of a limb pair when they are maximally spread
forwards and backwards. As forelimb span is much less than hindlimb
span in ground dwellers, the difference between total and anatomi-
cal strides is much greater for the forelimbs and they are both off the
ground for much longer periods than the hindlimbs.

The posterior body flexes laterally to some extent during rapid
locomotion towards the side on which the hindlimb is moving

Table 4 Some characteristics of open ground and climbing locomotion in
lacertids specialised to these activities.

Fast ground Vertical
Body close to substratum no yes
Anatomical stride of forelimbs short long
Hind leg delay some more
Crus extended right forwards yes no
Hind step length/snout-vent distance often >21 often < 1
Floating phase yes no
3 legs often in contact not usually yes
Toe 5 makes positive grip no often
Rise on toe tips at end of stride yes no

82

E.N. ARNOLD

Fig. 12 Movements of hind leg of ground dwelling lacertid when running (left — lateral views, right — dorsal views). a. Beginning of power stroke: limb
extended anterolaterally with toes 1-4 directed forwards and spread with claws inserted in substratum. b. Crus flexes on femur. c. Femur begins to retract,
crus becomes more horizontal as femur rotates forwards and the metatarsal segment rises and is turned laterally bending the toes. d. Femur continues to

retract, crus and metatarsal segment extends backwards and lizard rises on tips of toes 2-4.

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

forwards. This increases the length of the hind limb step which in
the more long-legged species may be substantially longer than the
body. Wild Meroles anchietae about 60mm from snout to vent had
step lengths of 80-150mm (measured from tracks at Gobabeb,
Central Namibia in April, 1994). As might be expected from the
greater relative lengths of time they are in contact with the ground,
hind limbs are far more important in fast ground locomotion than
forelimbs. That they deliver more thrust can be seen from tracks in
sand where hind limbs produce footprints with a strong posterior
pressure wave caused by their powerful backward extension,
whereas forelimbs tend to produce simple shallow pocks, indicat-
ing that their main role is to provide intermittent support to the
foreparts.

Movements of the hind limb (Fig. 12)

When animals are running fast, the hind leg is brought forwards so
that it is extended in generally anterolateral direction with the main
axis of the metatarsal segment often lying approximately para-
sagittally or somewhat anterolaterally and digits 1-4 directed
forwards and spread (Fig. 12a). The femur lies roughly in the
horizontal plane, while the crus is directed obliquely downwards and
the foot is placed flat on the ground with the claws of toes 14 flexed
downwards and inserted into the substratum. Toe 5 often projects
more laterally.

In the first phase of the power stroke, the crus flexes on the femur
(Fig. 12b). This results in the femur moving forwards but, as the line
of flexion of the knee is offset mesially, its distal extremity passes
over the crus which changes orientation so that, from being directed
anterolaterally, the crus swings until it is directed ventroposteriorly
in a parasagittal plane.

At this stage, the femur begins to be retracted, its distal end
descends somewhat and it also rotates forwards (when viewed from
above) about its long axis (Fig. 12c). The crus also again becomes
less flexed relative to the femur and these various movements
change its orientation, so that it becomes more or less horizontal but
still lies in a parasagittal plane. As this occurs, the metatarsal
segment rises proximally, beginning with its lateral edge, so that it is
now directed downwards and outwards. In firm substrata, the claws
maintain their position so that this reorientation of the metatarsus
then results in some mesial bending of the toes in the horizontal
plane to accommodate it; however flexing is limited by the stiffness
of the toes in this direction.

The femur continues to be retracted until it is directed
anteroposteriorly (12d).At the same time the crus unflexes further so
that it maintains its parasagittal orientation. By now, the metatarsal
segment is completely lifted from the ground and this raises the base
of the toes which, as well as being bent mesially, become flexed
downwards and the lizard rises on to the tips of toes 14 and then just
2-4 so that, at this stage, it is hyperdigitigrade. Final thrust in the step
is thus delivered entirely through the claws which act like the spikes
on an athlete’s running shoes. During this phase the whole leg
extends and the upper surface of the metatarsal segment may even be
directed anteroventally.

During a step, the lizard thus uses extension of all parts of the
hindleg to provide thrust: femur, crus, metatarsals and digits. After
this the muscles controlling the ventral tendons of toes 24 may
relax so these digits dorsiflex and the claws are pulled free. Toe 5
plays very little part in fast locomotion in specialised ground dwell-
ers and leaves the ground at an early stage.

In the rapid recovery stroke, where the hind limb is brought
forwards before the next step, it is raised high, partly flexed and then
extended forwards. During this process, the femur is protracted and
its forward rotation is maintained, so that forward flexion and

83

extension of the leg takes place more or less in the horizontal plane
and the foot is oriented with its mesial edge downwards. This allows
the distal portions of the limb to be kept well clear of the ground, so
that it is less likely to be impeded by any irregularities in the
substratum or by projecting plants. It also means that when the foot
does make contact with the substratum at the beginning of the power
stroke, it may still be orientated with its mesial edge downwards,
although it is then immediately placed flat on the ground as a result
of backward rotation of the femur. If the toes do encounter an object
that hinders their forward motion during the recovery stroke, the fact
that the upper surface of the foot is directed forwards means that they
can simply be passively ventriflected and brushed aside, so the leg
can still progress anteriorly. The toes are also capable of passive
lateral movement around their joints with the metatarsals, especially
when the foot is in the process of being placed sole-downwards on
the ground.

There is some variation in fast hind leg motion in armatured
ground-dwellers, which may partly result from the nature of the
substratum and its irregularities. Thus the foot may be clearly
directed anterolaterally at the beginning of the power stroke and the
claws may slip in loose soils so that the foot tends to rotate outwards
more at the end of a step. Some species also have characteristic
features during fast ground locomotion; for instance, in Acantho-
dactylus boskianus the foreparts are carried particularly high.

Rotation of the femur and supposed restrictions on its movement
Rotation of the femur about its long axis is a very significant feature
of hind leg movement during locomotion (Rewcastle, 1983). It
enables the path of extension of the crus during the power stroke to
be different from that of its flexion, allows the leg to be brought
forwards orientated more or less in the horizontal plane well above
the ground, and explains why the foot may be initially put down
mesial edge first.

It has sometimes been assumed that the femur in lizards cannot be
adducted far posteriorly because its trochanter was believed to jam
against the ventral rim of the acetabulum (Rewcastle, 1983). How-
ever, in all the lacertids studied, substantial posterior adduction is
regularly observed and no restriction of the kind envisaged is
observable in skeletal material.

The supposed problem of crural rotation

There has been considerable discussion of a supposed problem of
rotation within the distal hind limb (see for instance Rewcastle,
1983). If the foot is assumed to maintain its position during the
power stroke, while the angle of the femur in the horizontal plane
changes relative to it during adduction, there would have to be a
rotational twist within the intervening crural area, to accommodate
the change in relative position of these elements. The screw-like
nature of the mesotarsal joint between the crus and foot actually
permits some twisting (Rewcastle, 1980) and various other factors
reduce the amount that is actually required: 1) The angle of the knee
joint allows the crus to swing, from being in line with the femur at
the beginning of the power stroke to being directed backwards,
without disturbing the foot; 2) forward rotation of the femur and
descent of its distal extremity also helps minimise twisting of the
lower limb; this is also true of 3) reorientation of the metatarsal
segment, 4) bending of the toes, and 5) the general mobility of the
tarsal area. These factors, involving changes in orientation of the
distal femur and of the proximal foot preclude any substantial
problem of crural rotation.

A partial model of hind limb movement
The movements of the hind leg of lizards during locomotion take

84

place in three dimensions and are not always easy to envisage from
a written description and diagrams. However a clearer idea of some
of the main aspects can be obtained by making a simple model out of
a strip of card with folds inserted to represent articulations between
the main elements (Fig. 13). The model can be be used to demon-
strate the pattern of flexion between the femur and crus, the
subsequent reorientation of the latter element in the parasagittal
plane and associated lifting of the metatarsal segment brought about
by partial retraction and rotation of the femur, the benefits of femoral
rotation in allowing the limb to be partially retracted and extended in
the horizontal plane as it is brought forwards in the recovery stroke,
and the restricted nature of the problem of rotation in the crural
region. It should however be born in mind that there is more play in
the actual joints than the model indicates. Such a model is also useful
in appreciating the rather different motions of the hind leg in
climbing species.

Other hind limb gaits in ground-dwelling lizards — continuous
gearing
Although lizards are often stated to have only a single gait, in
contrast to many mammals, the hind limbs are used in a range of
ways that are largely correlated with speed. Stationary lacertids may
commence movement by thrusting with both hind legs, especially if
startled, so accelerating before a step pattern is established. In slow
walking, the excursion of the femur may be restricted and, instead of
being brought forwards, the crus may be kept largely flexed, so that
it is never directed forwards and the soles of the feet may be
orientated rather laterally, a result of forward rotation of the femur.
At increasing speeds, femoral excursion is greater and the crus
may be brought forwards until it is roughly perpendicular to the
body with the foot directed anteroposteriorly. Finally, the crus is
extended fully forwards and the femur rotated backwards at the
beginning of the power stroke, as described above. These substantial
changes in the way the hindlegs are used act like continuously
variable gears. As might be expected, the body is held closer to the
ground in the slower gaits as forward rotation of the femur during
these permits a more lateral use of the whole limb.

Movements of the foreleg in ground-dwellers

At the beginning of the power stroke, the humerus is directed antero-
laterally and the lower limb and digits point forwards. During
retraction the forelimb turns over until its underside is uppermost. At
first the manus is placed palm-down, but the lizard rises on the distal
toes as the lower limb becomes more or less vertical. However, the toes
usually dorsiflex at the end of the stride. As with the hind leg, the fore-
leg is raised high when it is brought forwards in the recovery stroke.

Functional aspects of the limbs and feet of ground-dwelling
lacertids

It is now possible to assess the functional importance of limb
morphology in ground dwelling lacertids. The long legs, in which
the more distal elements — crus, metatarsal segment and digits — are
differentially elongated, are responsible for the extended stride of
these species, and the way the metatarsal bones are bound closely
together in some forms increases the rigidity of the metatarsal

E.N. ARNOLD

segment. The way the main adductor muscles, especially the
caudifemoralis, are attached proximally to the femur confers high
mechanical advantage on the locomotory system, which in this
respect and the elongation of its distal elements parallels those of
other fast amniote runners such as horses.

The regular downward curve of the toes, maintained by joint
capsules and tension in the dorsal and especially ventral tendons at
the end of the stride, and the restriction on medial flexion, ensure
that thrust is delivered to the ground efficiently. The robust phalanges
with joints of restricted flexibility are clearly suitable for resisting
the compressive and shearing forces produced at this time, when the
lizard may sometimes be balanced on the tips of very few toes.
Steady increase in length from the first toe and its metatarsal to the
fourth means that the claws of these digits can be well-spaced when
inserted in the ground, ensuring a wide area of contact with the
substratum so a good grip is more likely, even on shifting surfaces;
the generally large size of the foot also contributes to this spread and
the long lightly curved claws are more likely to gain effective
purchase in earth or sand than short recurved ones. Reduction of the
fifth toe is comprehensible in as much as it is virtually unused in fast
locomotion.

The very robust phalanges of the manus may not be specifically
associated with locomotion but could be important in digging,
something advanced ground lacertids accomplish largely (or en-
tirely in the case of Heliobolus lugubris, personal observations) with
their forelegs. Possibly the relatively large manus of soft-sand
dwellers is also functionally associated with digging.

Ground locomotion in climbing species

Lizards that habitually climb, like Lacerta oxycephala, L. perspi-
cillata and to a lesser extent, L. nairensis, run quite efficiently on the
ground and often extend the crus fully forwards. However, they tend
to carry the body less high than specialised ground-dwellers, partly
because their limbs are generally shorter and the crus especially so,
and these features also limit stride length. Habitual climbers do not
rise on to the tips of their toes at the end of the stride and, instead of
the digits flexing downwards, they flex dorsally, toes 24 bending at
the penultimate articulation between the phalanges, so the pes
rotates over the inserted claws (Fig. 17b). This shortens effective
stride length still further. Climbing species also tend to keep the hind
limb closer to the substratum during the recovery stroke.

The distinctive features of ground locomotion in habitually climb-
ing forms all have functional advantages during climbing (p. 000).A
similar but more extensive carry over of features advantageous in
climbing to horizontal locomotion occurs in the gecko, Gekko gecko
(Zaaf, Aerts et al., 1997).

Locomotion in climbers on steep open surfaces
(Figs 13-17)

Most detailed observations were made of Lacerta oxycephala,
which was filmed dorsally and laterally when climbing on a near
vertical rock slab. L. perspicillata, Algyroides nigropunctatus and A.
marchi were also examined by film or video; in most cases, speeds
and exposures were the same as for many ground dwelling lizards
but Algyroides nigropunctatus was also videoed at 200 fields/sec.

\

digits

1
1 \
metatarsal
;

1

segment \

\

Fig. 13 Simple model of right hind limb of lacertid. A strip of card cut and folded as indicated by broken lines can be used to demonstrate the main

movements of the hind leg elements in a running lizard.

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

85

c d

Fig. 14 Views of specialised climbing lacertid ascending vertical surface; a, b dorsal; c, d lateral. Crus and foot are not extended far forwards and hind
digits flex mesially at end of power stroke, the body is kept very close to the surface being climbed.

Many lacertids climb on open continuous surfaces such as rocks
and tree boles and branches. These vary in steepness, from gentle
slopes to vertical and even overhanging surfaces, and lizards may
run directly up them, or descend, or travel laterally or obliquely.
Locomotion in specialised lacertid climbers often has many simi-
larities to that of ground dwellers, but there are marked differences,
especially when ascending perpendicular and near-vertical faces.

In this situation, a lizard like Lacerta oxycephala climbs with its
body very close to the surface and the limbs spread laterally so the
distal extremity of the femur does not pass dorsal to the crus during
the power stroke (Fig. 14). As in ground dwellers, the limbs work in
diagonal pairs. Each hind foot is placed lateral and posterior to the
ipsilateral forefoot and the hind leg in each diagonal limb pair is
delayed relative to the foreleg so that, as the recovery phase is brief,
the proportion of time when two feet are out of contact with the
substratum is small. In observed sequences of climbing in Lacerta
oxycephala, the recovery phase took between an eighth and a quarter
as long as the power phase, the smaller proportion being during slow

climbing. Counts of the number of frames of cine film in which four,
three and two feet gripped the rock suggest that four legs may be in
contact for over half, and three legs for over three-quarters of the total
time; there is consequently no floating phase. This pattern contrasts
strongly with fast locomotion in specialised ground dwellers where
two legs are usually out of contact with the substratum and sometimes
all four. The distance between the consecutive foot holds is more or
less equal for both fore and hind limbs, being about half to threequarters
of the snout-vent distance in the locomotory sequences studied.

Movements of the hind limb

The excursion of the hind limbs is relatively restricted and although
the femur is directed anterolaterally at the beginning of the power
stroke (right hind limb, Fig. 14a,c), the crus is not brought fully
forwards at this time and is usually, directed approximately normal
to the body axis. The metatarsal segment, which is mesially in-
flected, is then directed anterolaterally and is placed flat on the
substratum.

Fig. 15 Flexing in the hind toes of a climbing Lacerta oxycephala at the end of the step. a. oblique lateral view showing flexion in the sagittal plane of the

toes. b. dorsal view, showing mesial flexion of toes 1-4.

86

Often the digits are spread radially with all the claws inserted in
minor irregularities in the substratum and the well developed toe 5
contributing positively to the grip of the hind foot. Toes 1—3 are
often directed more or less anteriorly, 4 laterally or somewhat
posteriorly and 5 posteriorly. Sometimes, instead, toes 3 and 4 may
both be directed obliquely backwards, or toes 1-4 are all directed
forwards.

As the crus flexes on the femur and the body of the lizard moves
forward, it becomes directed posterolaterally, changing its orienta-
tion to the foot. This results in the metatarsal segment being
directed more laterally and its posterior edge rising; because the
claws are firmly inserted, digits 1-4 flex mesially to accommodate
this change in orientation of the metatarsal segment (right hind leg,
Fig. 14b; Fig. 15). There is also a tendency for the crus to thrust
diagonally backwards at this stage which accentuates the bending
of the toes. At the same time, the proximal parts of toes 14 flex
upwards in the vertical plane mainly at the following phalangeal
articulations toe 1 —0/1, toe 2 — 1/2, toe 3 — 2/3, toe 4 — 2/3 and 3/4.

The femur is then retracted and the crus is extended posteriorly
relative to it, thrusting the body of the lizard upwards (right hind
leg, Fig. 14b). The metatarsal segment does not rise much as a
whole but its hind edge continues to do so and, as this happens, the
claw of toe 5 becomes detached, followed by that of toe 4 (if this
digit is not directed forwards), and then those of the remaining toes
as the foot moves rapidly forwards to gain a new grip further up the
rock face. This recovery stroke takes place with the foot close to the
substratum.

In contrast to ground locomotion, the femur of specialised
climbers seems to be rotated forwards around its long axis for most
of the step cycle, allowing the limb to work largely in a plane more
or less parallel to that of the substratum.

Movements of the fore limb

After its recovery stroke, the forelimb is extended forwards with the
humerus directed roughly anterolaterally, the lower limb forwards
and the digits broadly spread (right limb, Fig. 14b,d) As the
humerus

retracts and the lower limb flexes on it, the latter rotates in a
parasagittal plane, becoming orientated first normal to the substra-
tum and then directed posteroventrally as the limb thrusts backwards
(right limb, Fig. 14a, c). After this the digits flex dorsally and the
claws are then released from their contact with the rock face, as the
next recovery stroke begins.

Other patterns of locomotion in specialised climbing lacertids
On less steep surfaces a climbing lizard like Lacerta oxycephala
shifts to a locomotory pattern essentially similar to that which
specialist climbers use on the ground (p. 85). When running down
a very steep slope, upward motion is presumably powered substan-
tially by gravity, but descent is controlled by the lizard taking short
steps in which the hindlimbs are turned back with toes 4 and 5 and
often 3 directed posteriorly (Fig. 16). At the end of a step, in which
the femur is not moved much, the ventral tendons of these digits are
relaxed, loosening the grip of the claws. The foot is then brought
forwards, still directed posteriorly, and the claws flexed and in-
serted again; after this the leg extends backwards and the cycle is
repeated.

Problems of upward vertical locomotion

The problems encountered by a lizard climbing a vertical face are
quite different from those of an animal running on relatively level
ground. 1. There is a need to keep upward thrust parallel with the
surface being climbed. Although the oblique thrust delivered to the

E.N. ARNOLD

Fig. 16 Position of toes of right hind foot in Lacerta oxycephala
descending a rock face; 3,4 and 5 are turned posteriorly.

substratum by the hind limbs of arunning lizard tends to push it a way
from the ground into a floating phase, gravity returns it rapidly. There
is no such automatic restoration of contact on a vertical face and
oblique thrust would push the lizard right off the substratum. Thrust
must consequently be applied in a direction parallel to the face. 2.
There is a constant danger of falling from the face being climbed. In
particular, were there no foreleg contact, a lizard would tend to fall
outwards because it is then in a position of unstable equilibrium with
its centre of gravity above the remaining hindleg contact. The con-
verse condition, with both hind legs free, is less precarious as the
posterior part of the body tends to rotate towards the rock. 3. As
gravity acts in a direction diametrically opposite to that of locomo-
tion, momentum will be lost very quickly once upward thrust ceases;
this must therefore be regular and continuous.

Many characteristics of locomotion, in lacertids that climb vertical
faces regularly, appear to ameliorate these problems. Keeping the
body and limbs close and parallel to the surface being climbed
ensures that backward thrust delivered through the claws is also more
or less parallel to it. The danger of falling off the face is minimised by
the way the number of feet in contact with it is maximised including
those of the particularly important forelegs. This positive engage-
ment of all feet in upward locomotion maximises thrust and makes it
available throughout the cycle. Thrust is also maximised by the way
flexion of the toes enables the claws to be kept in place as long as
possible. Bringing the crus forwards until it is not much more than
normal to the body axis is equivalent to moving in a relatively low
gear, compared with the anterolateral extension found in ground
runners travelling at speed, something that is also appropriate when
moving against gravity. Keeping the body and limbs close to the
substratum also maximises stride and restricts the downward lever-
age that the body would exert if it was held away from the substratum.
The tail also plays a part in ensuring the foreparts of the lizard do not
fall away from the face. It is held very close to the substratum and, if
the front legs cannot get a grip (for instance if a piece of smooth card
is interposed), the lizard can hold its upright position by stiffening its
body and tail and pressing the latter against the surface.

Functional aspects of the limbs and feet of specialised climbing
lacertids

The greater equality of fore and hind limb pairs in habitual climbers,
when compared with open ground dwellers, is important in allowing
the stride lengths of the two pairs to be matched and for the fore feet

NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS

to play a positive role in upward locomotion, presumably contribut-
ing thrust as well as attaching the foreparts. This contrasts with
ground runners where the forelimbs have at most a minor role in
delivering thrust. The fact that the hind limbs of habitual climbers
are relatively short overall is partly responsible for the low gear
nature of upward locomotion, as is the shortness of the crus com-
pared with the femur; when the crus is flexed towards the substratum
at some phases of the step cycle, its shortness permits the upper
limbs and body to remain close to the substratum.

The short sharp recurved claws on the feet of climbing forms
allow a firm grip on substrata like rock that do not permit much
penetration. The insertion of the ventral tendon on the distal phalanx
of each digit well away from the actual articulation (Fig. 17a, b)
means that it has high mechanical advantage and can flex the claw
effectively against the weight of the body, ensuring its grip is
maintained.

At the end of the recovery stroke, when the hind foot is reattached
to the substratum, the long third metatarsal allows the third toe to be
deployed easily forwards, laterally or backwards, depending on
where its claw can be inserted. The mobility of this toe and of
numbers 4 and 5 means that some or all of them can be opposed to
the remaining toes to give a positive grip on the substrate. The fact
that toe 3 can be turned backwards is also important in allowing its
claw to join those of digits 4 and 5 in acting as an intermittent brake
when the lizard runs rapidly down steep slopes. When the digits of
the hind foot are spread with their claws flexed and in the process of
insertion in the rock face, the dorsal and ventral digital tendons
contract emphasising the kinking of the phalanges in toes 3—S and so
shortening these digits. This shortening ensures a positive grip by
the opposed claws.

Shortness of the hind toes in specialist climbers helps to reduce
lateral foot displacement produced by outward thrust of the crus. In
the later stages of the power stroke, mesial flexibility of toes 2-4
permits the claws to remain in place. As the metatarsal segment turns
more laterally, these toes often become quite sharply bent in a plane
parallel to the substratum. This permits the claws to remain in place
and upward thrust to be generated for as long as possible. As the back
of the metatarsal segment lifts, downward flexion of the second
phalanges of toes 3 and especially 4 (Fig. 15a) enable the claws of
these often backwardly or outwardly directed digits to remain in
place longer, prolonging a positive grip.

Not only do forwardly directed toes flex mesially but, as the
metatarsal segment lifts and turns over, hind toes 3 and 4 bend
dorsally in the parasagittal plane if they are directed forwards (Fig.
17b). This flexion is concentrated at particular joints which enables
it to be more acute than if it were distributed throughout most of the
articulations of the toe; the shortness of some intermediate phalanges
also contributes to this. Such acute flexion means that the metatarsal
segment can stop closer to the rock face instead of being displaced
outwards.

Concentration of dorsal flexion is combined with the simultane-
ous ventral flexion of the claw, necessary to maintain its grip and, in
toes 3 and 4 and when backwardly directed, additional ventral
flexion of phalanx 2 on phalanx |. The areas of ventral flexion are
produced by tension in the main ventral tendon. Although tension is
likely to be more or less the same throughout the length of the
tendon, ventriflexion is combined with the intervening area of the
toe flexing dorsally. This differential action is an additional result of
toe kinking, coupled with the varied positioning of the tendon
relative to different articulations in the toe (Fig. 17a, b). Essentially
under the joints where the more distal phalanges flex downwards,
for instance in toe 4 at the articulation of phalanges | and 2 and 4 and
5, the tendon is displaced away from the joint. This differential

87

Fig. 17 Effects of digit kinking and tendon position. a. Fourth hind toe of
Lacerta oxycephala with claw newly inserted in rock face. b. Same toe
towards end of stride when metatarsal segment is lifting. Because the
ventral tendon (black) is displaced well away from from joints A and D
and consequently has greater mechanical advantage at them, the
articulations can be kept ventriflexed while joints B and C, where the
tendon is closer and mechanical advantage less, can simultaneously
dorsiflect in response to the movement of the metatarsal segment. Claw
grip can consequently be maintained right to the end of the stride. c.
Fourth hind toe of Lacerta agilis; because there is no inbuilt kinking or
marked differential tendon displacement, the toe simply bows upwards
when the ventral tendon is under tension

positioning means that the mechanical advantage of the tendon
varies with the particular articulation to which it is applying a
turning moment; thus advantage is great at the two articulations
where it is displaced downwards but weaker in between where, in toe
4, phalanx 2 articulates with phalanx 3 and 3 with 4. Consequently
the latter area can flex dorsally in response to lifting and forward
movement of the metatarsal segment, while those bordering it retain
their ventral flexion, maintaining the lowering of the toe below the
level of the metatarsal segment and the grip of the claw. The way the
toes of habitual climbers can flex simultaneously in two directions in
a plane perpendicular to the substratum and also bend mesially
contrasts with the situation in specialised ground dwellers. In these,
because joints are double headed and because there is no kinking and
the main ventral tendons do not show variation in degree of separa-
tion from particular joints, the digits simply curve upwards into a
regular arc (Fig. 17c); this places substantial restrictions on the
possibility of vertical climbing in these forms (see below).

88

Kinking of the hind toes of climbing lizards then is a very simple
feature that has profound effects on foot function: toes 3-5 can be
shortened to provide a positive grip; when directed backwards or
outwards, they can be displaced downwards so that they maintain
their claw contact with the substratum, even though the posterior
part of the metatarsal segment to which they are attached is rising;
simultaneous flexing in different directions in the parasagittal plane
is possible. Not surprisingly, such a simple but elegant and produc-
tive mechanism has arisen many times in climbing lizards (see
p. 77). As noted, it seems probable that the numerous variants in the
exact pattern of kinking within the foot that are found in lizards as a
whole (p. 77) are to a large extent functional alternatives rather than
adaptations to different situations.

The forefoot shows some functional similarities to the hind one.
The digits are spread very widely when the claws are first inserted
and possibly contraction within the palm draws the metacarpals
closer, tensioning the fingers. As in the hind limb, the shortness of
intermediate phalanges in digits 3 and 4 probably concentrate dorsal
flexion allowing it to be sharper and letting the forelimb be turned
over without being displaced much outwards. The peculiarities in
Holaspis have not been investigated in a living animal but they may
allow the limb to act even more effectively in a parasagittal plane.

In general the digits of climbing lacertids act differently from
those of habitual ground dwellers. Instead of the weight of the
animal being balanced on columns of phalanges at times, it is
supported by tension in the ventral tendons. The phalanges are
subjected to a compressive force by this but, because the tendons are
firmly attached by ligamentous sheaths at each joint, such force is
along the length of the phalanx and consequently exerts little shear.
Also, as the tendon insertion on the claw is offset from the pivot for
this on the penultimate phalanx, thus increasing its mechanical
advantage, compressive forces along the axes of the toes will be
reduced. The largely tensile role of the toes in climbers is reflected
in their slender phalanges and robust ventral tendons and the net
lateromesial compression of the toe this produces compared with the
toes of ground dwellers (Figs. 9b, 10).

Climbing in specialised ground dwelling lacertids

Members of the ground dwelling clade consisting of Latastia and its
sister group are incompetent climbers. In trials using single lizards
of each species, Meroles reticulatus could not climb a concrete slab
that was at a much steeper than 60°from the horizontal; the max1-
mum angle for Acanthodactylus erythrurus and A. scutellatus was
70°, and for A. boskianus 80°. In these species and other ground
dwellers such as Lacerta agilis, the hind toes cannot flex mesially or
dorsiflect as they do in specialised climbers; as already noted they
simply bow upwards instead. In contrast, specialised climbers like
Lacerta oxycephala and L. perspicillata could climb the slab with
ease when it was vertical or even overhanging by 10° or 20°.

CONCLUDING REMARKS

Limb proportions and foot morphology of lacertid lizards are obvi-
ously evolutionarily plastic and numerous changes in these features
have taken place within the family, often in different directions.
However, although extreme variants are quite different, virtually no
anatomical changes are obviously likely to be irreversible, in the
way that loss of phalanges or claws that occur in many gekkotans
seem to be. (Development of extra rows of scales on the sides of the
toes may be a possible exception).

Across the family, changes in limb proportions and foot structure
correlate quite closely with shifts in structural niche and the different

E.N. ARNOLD

locomotory problems that these entail. It is possible to interpret the
different morphologies in functional terms as conferring perform-
ance advantage in these situations. Clearly, locomotion in different
habitats requires different morphological features, in particular,
running on open ground, climbing on open surfaces and traversing
vegetation matrixes. Adaptation to any one of these reduces locomo-
tory effectiveness in the others. For instance, the robust, stiff digits
that allow ground dwellers to run partly on their toe tips restrict
climbing ability, while the flexible toes advantageous to climbers are
inappropriate for the most effective kind of ground locomotion.
Species which occur in a range of structural habitats consequently
must compromise in locomotory terms and are probably not
maximally effective in any one situation. Whether they always
converge on a functionally intermediate morphology or whether it is
sometimes more effective to be efficient in one area but accept
penalties in another is not yet clear. However, Podarcis pelopon-
nesiaca at Stymphalea, S. Greece, runs effectively on the ground and
also climbs readily on rock outcrops but it is very clumsy in the latter
situation compared with rock specialists. (Arnold, 1987).

The conflicting mechanical demands of locomotion in different
environmental situations and the fact that they are largely unresolvable
is one of the main reasons why mechanical aspects of habitat
comprise such an important parameter in the structure of lizard
communities (Arnold, 1984, 1987). Actually, it is not habitat per se
that causes the conflict but the fact that really efficient physical
compromises seem impossible.

Overall there is great homoplasy among lacertids not only in
structural niche but also in the locomotory mechanisms associated
with these.

ACKNOWLEDGEMENTS. N. P. B. Arnold helped with the video work, and
P. Crabb and G. Summons (Ministry of Defence, Woolwich Arsenal) pro-
vided some high-speed video facilities. J. Vindum, W. R. Branch, R. Arnold
and C. J. P. Arnold were active in field collection and observation. H. in den
Bosch donated essential specimens and, with W. R. Branch, M. Largen and J.
Vindum, provided information about habitat and behaviour. L. Hartley
collected data on the caudifemoralis muscle. C. J. McCarthy helped in a
variety of ways. N. Tinbergen and A. J. Cain supervised some of the earlier
parts of this study. I am grateful to all of them.

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Issued 25 June 1998

Hetereleotris georgegilli, a new species of
gobiid fish, with notes on other Mauritian

Hetereleotris species

ANTHONY C. GILL

Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 SBD, UK.

Synopsis. Hetereleotris georgegilli, described from six specimens, 19.7—22.5 mm SL, is distinguished from congeners by the
following combination of characters: second dorsal-fin rays I,10—11, usually I,10; anal-fin rays 1,9; scales ctenoid, restricted to
posterior part of body and caudal peduncle (behind segmented dorsal-fin ray 5—7); and head pores present (posterior nasal, median
anterior interorbital, posterior interorbital, infraorbital, postorbital and terminal lateral canal pores). Four additional Hetereleotris
species are recorded from Mauritius: H. apora, H. poecila, H. vinsoni andH. zanzibarensis. The first-named two species represent
new records for Mauritius. Limited data suggest that Mauritian Hetereleotris assort into different habitats.

INTRODUCTION

In 1995 the author participated in a six-week expedition.to survey
shorefishes of Mauritius, Indian Ocean, along with associates from
the Smithsonian Institution, J.L.B. Smith Institute of Ichthyology
and Port Elizabeth Museum. Among the fishes collected were six
specimens of a new species of the genus Hetereleotris Bleeker,
1874. The new species is herein described and compared with
congeners; other Mauritian Hetereleotris species are also dis-
cussed.

Hetereleotris species are distinguished from other gobiids by the
following combination of characters: half or more of lower part of
first gill slit closed by membrane; distinct, single-lobed mental
frenum; distinctive superficial neuromast arrangement below eye
(see Figs 1,2); first dorsal fin with six spines and pterygiophore
formula of 3-22110; and vertebrae 10 + 17 (Akihito & Meguro,
1981; Hoese, 1986).

The genus is most diverse in the western Indian Ocean, with 13
species (revised by Hoese, 1986); the present study brings the total
to 14. Only one described species [H. poecila (Fowler)] is known
from the Pacific Ocean, but it also occurs in the Western Indian
Ocean. However, Hoese (1986) noted that three undescribed species
occur in the Pacific (one from the West Pacific, one from Rapa and
one from Easter Island), and Gill & Reader (1992) recorded an
additional undescribed species from Middleton and Elizabeth reefs,
southern Coral Sea.

MATERIALS AND METHODS

Measurements to the snout tip were made to the midanterior tip of
the upper jaw; standard length (SL) from the snout tip to the
midposterior part of the hypural plate; head length from the snout
tip to the posterior (vertical), fleshy edge of the operculum. Eye
diameter was measured horizontally where greatest. Preanal,
predorsal and prepelvic lengths were measured from the snout tip
to the anterior edge of the first spine base of the relevant fin.

© The Natural History Museum, 1998

Distance between first and second dorsal-fin origins was meas-
ured between the anterior edges of the first spine base of each fin.
Caudal peduncle depth was the shallowest depth of the peduncle.
Caudal peduncle length was measured from the posterior edge of
the last anal-fin ray base to the ventral edge of the caudal pedun-
cle at the vertical through the posterior edge of the hypural plate.
Fin ray lengths were measured from the bases of the rays to their
tips. Caudal fin length was the length of the lowermost ray articu-
lating with the upper hypural plate (i.e., hypurals 3 + 4). Pectoral
fin length was the length of the longest ray. Pelvic fin length was
measured from the base of the spine to the distal tip of the fourth
segmented ray. The pattern of interdigitation of first dorsal-fin
pterygiophores with neural spines is given as a first dorsal
pterygiophore formula following the methods of Birdsong ef al.
(1988). Terminology of head pores and other methods of counting
and measuring follow Hoese (1986) or are self explanatory. Os-
teological details were determined from radiographs and from a
paratype that was cleared and stained for cartilage and bone
(Potthoff, 1984). Meristic and morphometric values are given first
for the holotype, followed where different by value ranges or
frequency distributions for the paratypes. Frequency distributions
are presented in the form ‘x fy,’ where ‘x’ is the count and ‘f’
indicates that the following value, ‘y, is its frequency. Where
counts were recorded bilaterally from the holotype, both values
are presented and separated by a slash; the first value given is the
left count.

Comparisons of H. georgegilli with congeners were based on
published data (particularly those provided by Akihito & Meguro,
1981, and Hoese, 1986), specimens obtained in Mauritius by
the author and colleagues (see below; museum codes follow
Leviton ef al., 1985), and the following specimens in The Natural
History Museum: H. bipunctata Tortonese, 1976, Yemen, Aden,
BMNH 1985.7.29.3-6 (3); H. diademata (Riippell, 1830), Gulf of
Suez, BMNH 1925.12.31.51 (1; holotype of Lioteres (Pseudo-
lioteres) simulans Smith, 1958); H. vulgare (Klunzinger, 1871),
Red Sea, BMNH 1979.6.20.40-43 (4); H. zonata (Fowler, 1934),
South Africa, Durban, BMNH 1919.4.1.21—22 (2), Persian
Gulf, BMNH 1900.5.8.93 (2), Mekran Coast, BMNH 1899.5.8.93
(1).

92

Fig. 1 Hetereleotris apora, diagram of head in lateral view showing
positions of superficial neuromasts of lateraosensory system (composite
based on several specimens from Mauritius).

SYSTEMATIC ACCOUNT

Hetereleotris georgegilli sp. nov.
Figs 2-6

HOLOTYPE. USNM 344315, 19.7 mm SL female, Mauritius, Flic
en Flac, 30 m north of entrance to lagoon, 20°16'S 057°22'E, around
small coral bommie on coral, coral-rock, sand and silt bottom, 4-10
m, A.C. Gill, D.G. Smith, M.J. Smale, W. Holleman, P. Clark and B.
Galil, OS May 1995 (field no. PCH 95-M20).

PARATYPES. Mauritius: BMNH 1997.10.24.1, 1: 20.3 mm SL
female (subsequently cleared and stained), BMNH 1997.10.24.2, 1:
22.5 mm SL male, RUSI 56870, 1: 19.8 mm SL female, collected
with holotype; USNM 344316, 1: 20.7 mm SL male, Albion, off
Pointe Petite Riviere at end of Avenue Victory, surge area and
adjacent gutters with sand, pebble and rock bottoms, 0-5 m, A.C.
Gill, M.J. Smale and W. Holleman, 15 May 1995 (field no. PCH 95-
M23): USNM 344317, 1: 22.3 mm SL male, Passe de L Ambulante,
off Le Morne, outside lagoon, 20°26°10"S 057°17’40"E, spur and
groove with surge, 6-8 m, P.C. Heemstra, A.C. Gill, D.G. Smith,

TLCP

Fig. 2 Hetereleotris georgegilli, diagram of head in lateral view showing
positions of laterosensory pores and superficial neuromasts (composite,
based primarily on holotype, USNM 344315, and cleared and stained
paratype, BMNH 1997.10.24.1). Abbreviations: AIOP, anterior
interorbital pore; AN, anterior nostril; IFP, infraorbital pore; PIO,
posterior interorbital pore; PN, posterior nostril; PNP, posterior nasal
pore; POP, postorbital pore; TLCP, terminal lateral canal pore.

A.C. GILL

Fig.3 Hetereleotris georgegilli, holotype, USNM 344315, 19.7 mm SL,
Flic en Flac, Mauritius.

M.J. Smale, W. Holleman, P. Clark, et al., 18 May 1995 (field no.
PCH 95-M30).

DIAGNOSIS. Hetereleotris georgegilliis distinguished from conge-
ners by the following combination of characters: second dorsal-fin
rays I,10—11, usually I,10; anal-fin rays I,9; scales ctenoid, restricted
to posterior part of body and caudal peduncle (behind segmented
dorsal-fin ray 5—7); and head pores present (posterior nasal, median
anterior interorbital, posterior interorbital, infraorbital, postorbital
and terminal lateral canal pores).

DESCRIPTION. Dorsal-fin rays VI + J,10 (1,10 £4; 1,11 f1); anal-fin
rays I,9; pectoral-fin pointed with 18/18 (16 f1; 17 £2; 18 f7) rays, the
lower | (0 f8; 1 £2) ray unbranched, remaining rays branched; upper
3-5 pectoral-fin rays with free tips; lower pectoral-fin rays slightly
thickened, more robust than upper rays; pelvic-fin rays I,5; branches
on first segmented pelvic-fin ray 5/4 (4 f10); branches on second
pelvic-fin ray 5/5 (4 £4; 5 £5; 6 f1); branches on third pelvic-fin rays
6/6 (4 f1; 5 f6; 6 f3); branches on fourth segmented pelvic-fin ray 5/
5 (3 f3; 4 f4; 5 £3); fifth “segmented’ pelvic-fin ray unbranched, with
few or no segments, much shorter than other segmented rays
(subequal to or shorter than spine) and inconspicuous (clearly
visible only after dissection; Fig. 4); pelvic fins fully separate,
without connecting membrane or fraenum (Fig. 5); segmented
caudal-fin rays 9 + 8; branched caudal-fin rays 8+ 8 (7+ 7 f1;8+7
f4); upper unsegmented caudal-fin rays 5 (4 fl; 5 £4); lower
unsegmented caudal-fin rays 4 (4 f2; 5 f3); vertebrae 10 + 17; first
dorsal pterygiophore formula 3-22110; anal pterygiophores preced-
ing first haemal spine 2; epurals 1.

Scales ctenoid, restricted to posterior part of body and caudal
peduncle, extending anteriorly as narrow midlateral wedge or band
to vertical through second dorsal-fin segmented ray 6/5 (5 5; 6 4;
7 f1; Fig. 6); lateral scale rows 11/11 (10 f2; 11 £5; 12 f1; 13 £2).

First gill arch broadly joined to suspensorium by membrane; gill
opening restricted to pectoral-fin base; branchiostegal rays 5.

Premaxilla with 3 or 4 irregular rows of conical teeth anteriorly,

——7 7 Tr
(pe SSG0RBenccc—a=:

SRS oO Se
a

SR1I+4

el

Fig.4 Hetereleotris georgegilli, cleared-and-stained paratype, BMNH
1997.10.24.1, 20.3 mm SL, ventral view of right pelvic fin and
basipterygium. Abbreviations: B, basipterygium; SP, spine; SR I—5,
segmented rays 1-5. Large stipple indicates blue-stained material (see
text); small stipple indicates interradial membranes. Arrow points
anteriorly. Scale = 1 mm.

MAURITIAN HETERELEOTRIS

reducing to | or 2 rows posteriorly, the teeth of outer row largest and
caniniform; inner row of teeth across front of premaxilla slightly
curved and enlarged; dentary with 3 or 4 irregular rows of conical
teeth anteriorly, reducing to a single row posteriorly, the outer row of
teeth largest and caniniform; inner row of teeth across front of
dentary slightly curved and enlarged; palatine and vomer edentate;
tongue edentate and weakly rounded to truncate, sometimes with
weak indentation anteriorly.

Cephalic sensory pores (see Fig. 2): posterior nasal 1/1; anterior
interorbital |; posterior interorbital 1; infraorbital 1/1; postorbital 1/
1; lateral canal 0/0; terminal lateral canal 1/1. Distribution of super-
ficial neuromasts (cutaneous papillae) on head as shown in Fig. 2.
Male urogenital papilla pointed posteriorly, with inconpicuous lobe
on either side of narrow gonopore, the posterior edge of papilla
papillose; female urogenital papilla subrectangular, truncate, with
weak lobe on each side of wide gonopore, the gonopore rim papil-
lose. Epaxial musculature extending anteriorly to posterior
interorbital pore.

As percentages of SL: head length 32.0 (30.7—32.4); eye diameter
9.6 (9.0-10.1); head width at posterior preopercular margin 24.9
(23.3—28.0); head depth at posterior preopercular margin 18.8 (17.5—
19.7); body depth at pelvic-fin origin 20.3 (18.4—20.2); body depth
at anal-fin origin 16.8 (16.2—17.2); caudal peduncle depth 11.2
(10.2-11.1); caudal peduncle length 19.3 (17.9-19.6); predorsal
length 40.1 (38.1—39.4); prepelvic length 30.5 (28.9-31.3); preanal
length 58.9 (58.6—60.0); distance between first and second dorsal-
fin origins 19.3 (17.9-20.7); second dorsal-fin base length 27.4
(27.6—28.8); third dorsal-fin spine length 10.7 (11.6—14.3); third
from last segmented dorsal-fin ray length 14.7 (14.5—16.1); anal-fin
base length 23.9 (21.7—23.3); third from last segmented anal-fin ray
length 14.7 (14.6-15.7); pectoral fin length 29.4 (27.1—30.5); pelvic
fin length 22.8 (19.6-23.2); caudal fin length 24.9 (24.4-26.3).

COLOUR OF PRESERVED SPECIMENS. Head and body pale brown
with dusky brown to grey-brown reticulate mottling, this darkest
dorsally; mottling forming about eight weak bars, the first through
upper base of pectoral fin, the last through base of caudal fin; last bar
dark grey, distinctly darker than all other bars; dusky grey bar
extending from anteroventral edge of eye to middle of upper lip,
contiguous ventrally with dusky grey bar or spots on lower lip and

Fig.5 Hetereleotris georgegilli, holotype, USNM 344315, 19.7 mm SL,
outline of pelvic fins in ventral view.

Fig.6 Hetereleotris georgegilli, holotype, USNM 344315, 19.7 mm SL,
diagram of posterior part of body and caudal peduncle showing
scalation. Arrow indicates vertical through posterior edge of hypural
plate.

chin; dark grey spot on upper part of pectoral-fin base, this extending
on to basal third of upper few rays; dorsal fins pale to hyaline with
diffuse dusky bars extending obliquely from each body bar; dorsal
fin sometimes with dark grey distal margin (observed only in two of
three males); anal fin pale to hyaline, sometimes with two or three
irregular dusky grey stripes; caudal fin pale to hyaline, with dark
grey basal bar (see above) and about five to eight irregular dusky
bars; pectoral fins pale to hyaline with dark grey spot dorsally (see
above) and irregular dusky bars; large white spot immediately below
and behind dark spot on upper part of pectoral fin, the white spot
edged posteriorly in dusky to dark grey; pelvic fins pale, sometimes
with scattered melanophores basally.

COLOUR IN LIFE. Not recorded.

ETYMOLOGY. ‘The specific epithet is in memory of my father,
George Burton Gill (1925-1994).

COMPARISONS WITH OTHER HETERELEOTRIS SPECIES. Hoese’s
(1986) key to western Indian Ocean Hetereleotris identifies speci-
mens of H. georgegilli as H. nebulofasciata (Smith, 1958), a species
currently known only from east Africa (Kenya to Mozambique) and
the Comores (R. Winterbottom, pers. comm.). Hetereleotris
georgegilli and H. nebulofasciata differ from congeners in having
the following character combination: scales confined to posterior
part of body and caudal peduncle; head pores present; and
preopercular pores absent. The two species also have a similar
preserved colour pattern. However, H. georgegilli differs from H.
nebulofasciata in having: fewer segmented rays in the second dorsal
fin (10-11, usually 10 versus 11); fewer segmented anal-fin rays (9
versus 9-10, usually 10); more pectoral-fin rays (16-18, usually 18
versus 15-16); ctenoid scales (versus cycloid); fifth segmented
pelvic-fin ray unbranched and short (versus relatively well-devel-
oped, slightly shorter than fourth segmented ray, unbranched or
branched once); and a prominent dark spot on the dorsal part of the
pectoral fin (lacking in H. nebulofasciata).

Hetereleotris georgegilli resembles H. apora (Hoese & Winter-
bottom, 1979) from Mauritius (see below), South Africa, Saint
Brandon Shoals, the Comores and the Chagos Archipelago in hav-
ing: scales ctenoid and confined to caudal peduncle; and fifth
segmented pelvic-fin ray reduced (usually absent in H. apora).
Hetereleotris apora differs fron H. georgegilli in having: two
prominent opercular spines (versus spines lacking); fewer lateral
scales (4-6 versus 10—13); no head pores (versus head pores present);
fewer pectoral-fin rays (15-16 versus 16-18, usually 18); more
segmented second dorsal-fin rays (10-11, usually 11 versus 10-11,

94

usually 10); and more segmented anal-fin rays (9-10, usually 10
versus 9).

REMARKS. ‘Two of the three collections that yielded specimens of
H. georgegilli, were in surge areas (PCH 95-M23 and PCH 95-
M30), and the remaining collection was in an area exposed to tidal
currents (PCH 95-M20); all collections were in 4-10 m. Thus, H.
georgegilli appears to be restricted to shallow subtidal, high-energy
habitat.

The tip of the pelvic-fin spine of the cleared and stained paratype
of H. georgegilli took up alcian blue stain (Fig. 4). Birdsong et al.
(1988: 197) noted similar blue-staining in Awaous and sicydiine
gobiids and interpreted ‘a fleshy (cartilaginous) tip on each pelvic
spine’ as a potential synapomorphy of these taxa. However, histo-
logical studies in progress by L.R. Parenti and the present author
indicate that fin spines of many acanthomorphs stain with alcian
blue, but that the blue-staining material is keratin not cartilage.

COMMENTS ON OTHER MAURITIAN
HETERELEOTRIS

ECOLOGICAL NOTES. Hoese (1986) recorded two species of
Hetereleotris from Mauritius, H. vinsoni Hoese, 1986 and H.
zanzibarensis (Smith, 1958). The 1995 collections yielded both of
these species and three others: H. apora (Hoese & Winterbottom,
1979), H. georgegilli, and H. poecila (Fowler, 1946). Specimens of
Hetereleotris were collected at thirteen stations (Table 1). Details for
three of the stations (PCH 95-M20, PCH 95-M23 and PCH 95-M30)
are provided above in the list of type materials for H. georgegilli.
Locality and habitat details for the remaining ten stations are as
follows:

PCH 95-M1: Bai de la Petite Riviere, off Albion Fisheries Re-
search Centre, around coral bommies on sand and rubble bottom,
0.3-1.9 m.

PCH 95-M5: Bai de la Petite Riviere, just south of Pointe Petite
Riviere at north end of Albion public beach, around rocks and
patch reefs on sand, rock and rubble bottom, 0—1.5 m.

PCH 95-M9: Albion, Pointe Petite Riviere at end of Avenue
Victory, rock pools, 0-1 m.

PCH 95-M10: Bai de la Petite Riviere, off Albion Fisheries
Research Centre, 20°12’30"S 57°23'E, boulders on sand and
gravel bottom, 10—12 m.

PCH 95-M11: Bai de la Petite Riviere, off Albion Fisheries
Research Centre, 20°12’00"S 57°23'E, around coral bommie and
adjacent coral, rubble and sand, 9-11 m.

PCH 95-M13: Bai de la Petite Riviere, southwest of Albion
Fisheries Research Centre, around coral bommie, 10—11 m.
PCH 95-M18: Bai de la Petite Riviere, off Albion Fisheries
Research Centre, just outside reef crest, 20°12’30"S 057°23’30"E,
around caves and along 2—3 m dropoff in front of reef platform, 4—
8 m.

PCH 95-M22: Trou aux Biches lagoon near boating channel,
around coral bommies and patch reefs (mainly Acropora) and
adjacent sand and rubble, 4-5 m.

PCH 95-M27: Albion, off Pointe Petite Riviere at end of Avenue
Victory, 10-11 m.

PCH 95-M32: rocky shore at Bel Air, 20°30’30"S 57°34’30"E,
rock pools, 0-1 m.

Despite the limited data, there is some indication of ecological
separation of the species (Table 1). Of the 13 stations that yielded
specimens of the genus, one had three species, seven had two

A/G GIEE

Table 1 Number of specimens of Hetereleotris collected by the author
and associates in Mauritius in 1995. See text for locality and habitat data
for each station.

PCH 95-M station number
1S) SOO" 1 AS ss 20022) 23 ies Ose

H. apora = Se Tee: 2S. 34. 8 ee
H. georgegilli ee ee eee en |

H. poecila = <= 5. 0 =

H. vinsoni Saii?? = ears I
Ei zanzibarensis’ (Sey a2 | 1 Ses Aa

species, and five had only one species. Overlap can be largely
attributed to a single species, H. zanzibarensis; it was collected from
a variety of habitats ranging from rock pools to reefs in 0-12 m, and
was present at each of the stations that yielded more than one
Hetereleotris species. The remaining species were collected from
more restricted habitats: H. apora from around bommies, reef and
boulders in 4-12 m;H. georgegilli from surge and tidal-current areas
in 4-10 m;H. poecila from rock pools in 0-1 m; and H. vinsoni from
around coral bommies and patch reefs in 0.3—1.9 m.

TAXONOMIC NOTES. Hetereleotris apora. Hoese & Winterbottom
(1979) described H. apora (as Lioteres aporus) from four specimens
from Sodwana Bay, South Africa. Winterbottom & Emery (1985)
recorded the species from the Chagos Archipelago, and Hoese
(1986) recorded it from Saint Brandon Shoals. R. Winterbottom
(pers. comm.) has also collected it recently from the Comores.
Sixteen specimens collected by the author and associates represent
a new record for Mauritius: PCH 95-M10 [USNM 344319 (1
spec.)]; PCH 95-M13 [USNM 344320 (2)]; PCH 95-M18 [BMNH
1997.10.24.3 (1), RUSI 56871 (1), USNM 348368 (1)]; PCH 95-
M20 [BMNH 1997.10.24.4—S (2), RUSI 56872 (2), USNM 344321
(4)]; PCH 95-M27 [BMNH 1997.10.24.6 (1), USNM 344322 (1)].
The Mauritian specimens agree well with the descriptions given by
Hoese (1986) and Hoese & Winterbottom (1979), except that the
superficial neuromasts are more extensive (cf. their Fig. 2 with Fig.
1). However, this apparent difference is probably not real as superfi-
cial neuromasts are easily abraded and often difficult to see.
Hetereleotris poecila. Fowler (1946) described H. poecila (in his
new monotypic genus Riukiua) based on a specimen from Aguni
Shima, Ryukyu Islands. Akihito & Meguro (1981) reported on
additional specimens from Japan, and Hoese (1986: 14) extended
the range to include Taiwan (two specimens), Grand Comore Island
(one specimen) and Sri Lanka (23 specimens). Its range is further
extended here to Mauritius based on ten specimens collected by the
author and associates: PCH 95-M9 [BMNH 1997.10.24.7-8 (2
specs), RUSI 56873 (1), USNM 344333 (2)] and PCH 95-M32
[BMNH 1997.10.24.9 (1), RUSI 56874 (1), USNM 344334 (3)].
Hoese (1986) noted slight differences in pectoral-fin ray number
between the Pacific and Indian Ocean specimens: 16-18 with a
strong mode of 17 for Indian Ocean specimens versus 16 or 17 with
a weak mode of 16 for Pacific Ocean specimens. The following
counts were observed in the Mauritian specimens (adult specimens
checked only; bilateral counts included): 17 fl; 18 f13. More
materials are needed to determine the systematic significance of the
relatively high numbers of pectoral-fin rays in the Mauritian speci-
mens. The specimens agree in all other respects with the descriptions
provided by Akihito & Meguro (1981) and Hoese (1986).
Hetereleotris vinsoni. Hoese (1986) described H. vinsoni from the
holotype and 14 paratypes from Mauritius, and from two paratypes
from Saint Brandon Shoals; he also listed a non-type specimen from
Mozambique. Seven specimens were collected by the author and
associates in Mauritius in station PCH 95-M1 [BMNH 1997.10.24.10

MAURITIAN HETERELEOTRIS

—11 (2 specs), RUSI 56875 (1), USNM 344318, (2)] and PCH 95-
MS [USNM 348369 (2 specs)]. The specimens agree well with
Hoese’s original description and figures of the species. (Note that
Hoese’s Fig. 5 of the cephalic laterosensory system of this species
has been inadvertently swapped with his Fig. 3 for H. margaretae.)

Hetereleotris zanzibarensis. Smith (1958) described H. zanzibar-
ensis from a specimen from Zanzibar (as a new genus and species of
eleotrid(id), Satulinus zanzibarensis); later (Smith, 1959) he
described the species a second time (as a new species of gobiid,
Monishia oculata) from specimens from Mahé, Seychelles (type
locality), Kenya and Mozambique. Hoese (1986) extended its range
to include the Agelega Islands, Saint Brandon Shoals and Mauritius,
and R. Winterbottom (pers. comm.) has recently collected it at the
Comores. Thirty-eight specimens were collected by the author and
associates in Mauritius: PCH 95-M1 [BMNH 1997.10.24.12—13 (2
specs), RUSI 56876 (1), USNM 344323 (2)]; PCH 95-M5 [USNM
344324 (1)]; PCH 95-M9 [USNM 344325 (2)]; PCH 95-M10
[USNM 344326 (1)]; PCH 95-M11 [USNM 344327 (1)]; PCH 95-
M18 [BMNH 1997.10.24.14—18 (5), RUSI56877 (4), USNM 344328
(9)]; PCH 95-M20 [BMNH 1997.10.24.19 (1), USNM 344329 (1)];
PCH 95-M22 [BMNH 1997.10.24.20 (1), RUSI 56878 (1), USNM
344330 (2)]; PCH 95-M23 [USNM 344331 (2)]; PCH 95-M30
[USNM 344332 (2)].

Hoese (1986) noted that H. zanzibarensis varies considerably in
the development of the pelvic-fin disc, with some specimens pos-
sessing a complete disc (i.e., with a low fraenum connecting the
spine bases and a membrane connecting the fifth segemented rays)
and others possessing barely united pelvic fins (i.e., no apparent
fraenum between spine bases and fifth segmented rays connected
only at their bases). This variation led Smith (1958, 1959) to place
Satulinus zanzibarensis and Monishia oculata in separate families;
until recently, development of the pelvic-fin disc was the primary
basis for separation of the Gobiidae from the Eleotrididae. The
Mauritian specimens examined here agree well with the pelvic-fin
variation noted by Hoese (1986); approximately half of the speci-
mens have a completely developed disc and the remainder have
incompletely united fins.

Hoese (1986) noted highly variable pectoral-fin-ray counts for H.
zanzibarensis. Similar highly variable counts were noted for the
Mauritian specimens examined here. Bilateral counts recorded from
a subsample of the specimens were: 16 f7; 17 £19; 18 f6.

95

ACKNOWLEDGEMENTS. I am grateful to the other members of the 1995
Mauritius expedition: P. Clark, B. Galil, P.C. Heemstra, W. Holleman, M.J.
Smale and D.G. Smith. I am particularly indepted to D.G. Smith for his
efforts and company during the sorting and identification of specimens at the
Smithsonian Institution. The success of the expedition owes much to the kind
assistance of D. Pelicier and of Mauritian Fisheries officials, particularly staff
of the Albion Fisheries Research Centre. Hetereleotris specimens were
radiographed by S. Davidson, and P. Hurst photographed the holotype of H.
georgegilli. Drafts of the manuscript were read and improved from comments
by D.F. Hoese, N.R. Merrett, R.D. Mooi and R. Winterbottom.

REFERENCES

Akihito, P. & Meguro, K. 1981. A gobiid fish belonging to the genus Hetereleotris
collected in Japan. Japanese Journal of Ichthyology 28(3): 329-339.

Birdsong, R., Murdy, E.O. & Pezold, F.L. 1988. A study of the vertebral column and
median fin osteology in gobioid fishes with comments on gobioid relationships.
Bulletin of Marine Science 42(2): 174-214.

Fowler, H.W. 1946. A collection of fishes obtained in the Riu Kiu Islands by Captain
Ermest R. Tinkham, A.U.S. Proceedings of the Academy of Natural Sciences of
Philadelphia 98: 123-218.

Gill, A.C. & Reader, S.E. 1992. Fishes. pp. 90-93, 193-228. In: Reef biology: a survey
of Elizabeth and Middleton Reefs, South Pacific. Kowari 3: i—xviii, 1-230.

Hoese, D.F. 1986. Descriptions of two new species of Hetereleotris (Pisces: Gobiidae)
from the Western Indian Ocean, with discussions of related species. J.L.B. Smith
Institute of Ichthyology, Special Publication 41: 1-25.

Hoese, D.F. & Winterbottom, R. 1979. A new species of Lioteres (Pisces, Gobiidae)
from Kwazulu, with a revised checklist of SouthAfrican gobies and comments on the
generic relationships and endemism of western Indian Ocean gobioids. Royal
Ontario Museum, Life Sciences Occasional Paper 31: \—13.

Leviton, A.E., Gibbs Jr, R.H., Heal, E. & Dawson, C.E. 1985. Standards in herpetology
and ichthyology: Part 1. Standard symbolic codes for institutional resource collec-
tions in herpetology and ichthyology. Copeia, 1985(3): 802-832.

Potthoff, T. 1984. Clearing and staining techniques. pp. 35-37, in Moser, H.G.,
Richards, W.J., Cohen, D.M., Fahay, M.F., Kendall Jr, A.W. & Richardson, S.L. (eds),
Ontogeny and systematics of fishes. American Society of Ichthyologists and
Herpetologists Special Publication 1.

Smith, J.L.B. 1958. The fishes of the family Eleotridae in the western Indian Ocean.
Rhodes University Ichthyological Bulletin 11: 137-163, pls 1-3.

1959. Gobioid fishes of the families Gobiidae, Periophthalmidae, Trypauchenidae,
Taenioididae, and Kraemeriidae of the western Indian Ocean. Rhodes University
Ichthyological Bulletin 13: 185-225, pls 9-13.

Winterbottom, R. & Emery, A. 1985. Review of the gobioid fishes of the Chagos
Archipelago, central Indian Ocean. Royal Ontario Museum, Life Sciences Contribu-
tions 142: 1-82.

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Bull. nat. Hist. Mus. Lond. (Zool.) 64(1): 97-109

Issued 25 June 1998

Revision of Schismatorhynchos Bleeker, 1855
(Teleostei, Cyprinidae), with the description of
two new species from Borneo

DARRELL J. SIEBERT

Department of Zoology, Natural History Museum, Cromwell Road, London SW7 S5BD, UK

AGUS H. TJAKRAWIDJAJA

Balitbang Zoologi, Pusat Penelitian dan Pengembangan Biologi - LIPI, Jl. Juanda No 9, Bogor 16122, Jawa

Barat, Indonesia

CONTENTS

| af RCO(S (OYCLEN(O101, crates sian sha coReE Ee eb ty PERC re eococe eee o ee CEE eee

Materials and Methods .....................

GSE LIC PATE ONE ert corer cece cere eta nan Te Mecca cee den eaaws

SGHISIMATOMINTLENOS WSCC ROTM OOS Meat ics notes sandesrertreaver tecetet es ds uuasts vsaceubiaeahosae savuadyoe ceUpassd ditch Tunana cons twice oi stvesiesusasscovaiascoseacesesss 98
SIE CIES NEC OES ee etn gm enn. en er ASE LI POO, ono coersa sven ia cceagnyiaxencwepueecussiscinnct srnanssasesceittaseunencensenensdtenensneces 100
Key OM NE SPECIES ONS GNI ALO I MIIGHOS eee ie, nee taeda. Maken sata sinansus.tavecessincasctaegdttnarere an tuna tenets rtrseniN esr sneionearipextvasesCastcgiees 100
SCHISINALOMMYNGHO SEL TOMA CHO SN DICEKEN. GIS Ns. itinensssttecnsuecsott csadsantesssevsescanasssancoosass<aessnsesvoassrstlacsecadassseeevadhésaxesede 100

SC HISIIALOTMNMGHOS- NOLO MYM CHOSYSP MLO Vents: dices eatae aie -aa-suxesncesecx-seseessecesoscccc-sente tt atrewviacsccessaccuevecesocetuicaneterszcseoreessees 104
SCMISINAT GR DUNG Ost ENC AGATNGDUSNS [ikl O Von asmsws cvs Saeed va acvasueaaavdseesatssssdesassuidvesasvciascussicdesaeascacedtereuseacttvstiivassecausvststts 105
HEA BLE ILGIC OM AULSO US| metemeeatiemeant decmcvat soOMNtae< ca0s- chee sb orcsscececactes cWardnassterew-ntarivacseocPsneereecerrcecsecrsnceorarescedesurersaresderceecesere 107
WSIS TTS S1O Ue ene cee ea a poe cera chs Reto ea anu se spy nenes Sct ath tsacapabovaarieesersestavees sateonveretvee Mrumgereesenateastocteheressstedseessieescncteetectanetesttesacee 107
AMNOta ONS hKeyS Ome ph MIC e nena Of Te meet Onan. ccsux.ccosesecensecenee-cetncrctecesterecessacetes seen fesatssuncscsasesareasusetaeseasascaetenaetace 108
NEL ERCOWALSLE TENTS IS ceeaeer cole) Ae PORE eee CREEP EPEC apy Glo r r ROT ERR PRR on a ecEiy a oP oe Ri a rei St ea eo a een EE 108
GEGEN CGS scranase segs ax snes «vated ag sous fo xhi up ssnap as cas cananveticas favacaivadenesi'esanaa feces sterte rive aera us ct aetans sevtewea te scatecetoces tua tavectabeseabietreduevetet east 108

SYNOPSIS. Schismatorhynchos Bleeker, 1855 is revised: the genus is enlarged to accommodate two new species from Borneo,
Schismatorhynchos endecarhapis n. sp. is described from the Kapuas and Barito rivers, Kalimantan Barat and Kalimantan Tengah
and Schismatorhynchos holorhynchos n. sp. is described from the Rejang and Kinabatangan rivers Sarawak and Sabah, Malaysia.
Schismatorhynchos is characterised by oro-labial features, namely the upper lip not continuous with the lower lip around the
corner of the mouth, a wide crescentic lower jaw, the lower jaw lightly armoured with a thin, flexible, keratinous cutting edge and
a lower labial frenulum in which the mandibular laterosensory canal is located. Only S. heterorhynchos (Bleeker, 1853), the type
species, possesses the eponymous rostral cleft. Nukta Hora, 1942 is excluded from Schismatorhynchos on the grounds it lacks the
specialisations of the three Sundaland species.A key to species in the genus is provided and annotations to currently used regional

keys to cyprinid genera are suggested in order to accommodate an enlarged Schismatorhynchos.

INTRODUCTION

The cyprinid genus Schismatorhynchos Bleeker, 1855, with a dis-
junct distribution in Sumatra—Borneo and India, is known by a
strange rostral modification, a heavily tuberculate snout with a deep
horizontal cleft (Bleeker, 1853; Weber & de Beaufort, 1916; Hora,
1942). Two species, each in separate subgenera, are currently included
in Schismatorhynchos, S. (Schismatorhynchos) heterorhynchos
(Bleeker, 1853) from Sumatra and Borneo and S. (Nukta) nukta
(Sykes, 1841) from India. In addition to its unusual snout the
nominate subgenus is also known for unusual oro-labial morphol-
ogy which includes: 1) a frenulum connecting the lower lip to the
anterior gular region; and 2) a lower jaw with an elongated cutting
edge which separates the upper lip from the lower lip at the corners
of the mouth — the lips are not continuous around the corner of the
mouth (Weber & de Beaufort, 1916). Since the description of the
subgenus Nukta by Hora (1942) Schismatorhynchos has received
little attention except for listing in faunal reviews.

© The Natural History Museum, 1998

Schismatorhynchos heterorhynchos was described from Sumatra
(Bleeker, 1853) and Weber & de Beaufort (1916) reported it else-
where only from the Kapuas River, western Borneo. More recently,
Inger & Chin (1962) identified juvenile specimens from the
Kinabatangan River, Sabah, Malaysia (northeastern Borneo) as S.
heterorhynchos (Bleeker, 1853) even though this northeastern Bor-
neo material lacks a cleft snout. Since the Sabah specimens lack
tubercles on the snout in the region of the cleft in the snout of S.
heterorhynchos, and since S. heterorhynchos was known only from
larger specimens, Inger & Chin implied that the cleft in the snout
might not develop until maturity. Roberts (1989; Fig. 58) also
identified some juvenile material without a cleft snout, but from the
Kapuas River, western Borneo, as S. heterorhynchos. The oro-labial
morphology of the subgenus Schismatorhynchos is apparently so
distinctive that both Inger & Chin (1962) and Roberts (1989) were
able to identify material as belonging to it even in the absence of the
eponymous rostral cleft.

We collected juveniles of an unusual fish with a distinctive colour

98

pattern from the upper part of the Barito River basin, Kalimantan
Tengah, Indonesia (central Borneo) in Jan—Feb 1991, and a larger
specimen was taken subsequently in July 1992, again from the upper
part of the basin. The species proved difficult to identify to genus,
with a dorsal fin branched ray count of 11, a modal count of 33
lateral-line scales, the upper and lower lips not continuous around
the corner of the mouth, and an undivided, moderately tuberculate
snout. This Barito River material appeared identical to the illustra-
tion of a specimen from the Kapuas River identified as S.
heterorhynchos by Roberts (1989; Fig. 58). Examination of Kapuas
materials deposited by Roberts in the Museum Zoologicum
Bogoriense confirmed that the Barito materials are conspecific with
the Kapuas specimen Roberts illustrated. However, the disparity in
the counts of branched rays of the dorsal fin between the Barito—
Kapuas materials and that of S. heterorhynchos (eight branched rays
in the dorsal fin), and differences in colour pattern, led us to
conclude the Barito-—Kapuas materials in question are not S.
heterorhynchos, but instead are from a previously unrecognised
species of Schismatorhynchos.

In order to investigate the development of the snout cleft in S.
heterorhynchos, we examined small specimens from northeastern
Borneo identified as S. heterorhynchos (see Inger & Chin, 1962),
along with additional material collected in 1991 in Sarawak, Malay-
sia. Differences in snout tubercle structure and colour pattern led us
to conclude that the Sabah and Sarawak materials do not conform to
S. heterorhynchos either, but instead belong to yet another unrecog-
nised species.

More material has become available recently from the Kapuas
River, western Borneo (Sungei Sibau, an upper basin tributary of the
Kapuas River). This material possesses, even as juveniles of small
size, the oro-labial features of S. (Schismatorhynchos), a deeply cleft
heavily tuberculate snout and a colour pattern like that described for
S. heterorhynchos. Thus, at least two species of Schismatorhynchos
live within the Kapuas River basin, one species with a cleft snout and
another with an undivided snout.

To summarise our observations and clarify the status of material
identified in the literature as S. heterorhynchos, we revise the genus
Schismatorhynchos, describing two new species.

MATERIALS AND METHODS

Methods of measuring and counting follow Hubbs and Lagler
(1949). Vertebral (following Siebert & Guiry, 1996) and fin-ray
counts were taken from radiographs. Statistical analyses were car-
ried out using SYSTAT for WINDOWS, version 6.0 (SPSS, Inc.
1994), Institutional abbreviations are as follows: BMNH — The
Natural History Museum, London; FMNH — The Field Museum of
Natural History, Chicago; MZB —Museum Zoologicum Bogoriense,
Bogor; USNM — United States National Museum of Natural History,
Washington, D.C.; ZMA — Zoological Museum, Amsterdam.

The systematics and generic taxonomy of cyprinid fishes related
to Labeo Cuvier, 1817, i.e. those with a vomero-palatine organ, is in
a state of flux and is likely to remain so for some time to come. There
is considerable disagreement in the modern analytical literature as to
what subgroups should be recognised, just what their limits ought to
be, and at what rank they should be recognised (compare Reid
(1985; Table 1, p. 15) with Rainboth (1996; p. vii) to see conflict at
all the levels just mentioned). As regards this revision of
Schismatorhynchos, we adopt Rainboth’s rank of tribe for the entire
group of cyprinids with a vomero-palatine organ, and use the
informal name labeonin when referring to them in a general way. We

D.J. SIEBERT AND A.H. TJAKRAWIDJAJA

accept Reid’s restriction of Labeo, and, for the most part, his notions
of relationships within labeonins when discussing the limits of
Schismatorhynchos, because his groupings have been laid out fol-
lowing cladistic principles. We use Tylognathus Heckel (sensu
Bleeker, 1863; Reid, 1985, p. 277) when discussing our exclusion of
Nukta Hora from Schismatorhynchos because we are not sure of the
limits of Bangana Hamilton. Cyprinus nukta Sykes, 1838 may
belong in Bangana, but that assessment is beyond the scope of this
study.

GENERIC ACCOUNT
Schismatorhynchos Bleeker, 1855

Schismatorhynchus Bleeker, 1863; unjustified emendation.
Type species Lobocheilos heterorhynchos Bleeker, 1853; type by
monotypy.

DIAGNOsIS. Labeonins (sensu Reid, 1982, 1985; 1. vomero-pala-
tine organ present, 2. neural complex of the Weberian apparatus in
direct contact with supraoccipital region, 3. terete process of the
basioccipital, 4. superficial labial fold developed posterior to the
lower jaw) with a large, fleshy, sub-conical, rostral cap (=rostral fold
of Weber & de Beaufort, 1916); two pairs of barbels, posterior pair
in a deep recess at the corner of the mouth (largely to completely
hidden in large material); mouth inferior, wide, C-shaped; lower jaw
with an extremely long, thin, flexible, horny, cutting edge (Fig. 1A—
C); no superficial labial fold in advance of the upper jaw; upper lip
separated from rostral cap, moderately fleshy, adnate to upper jaw;
upper lip and lower lip not continuous around corner of mouth
(separated by extensions of the cutting edge of lower jaw); lower lip
reflected from lower jaw, thick, very fleshy, fringed, with a distinct,
elongate, longitudinally oriented, fleshy, lateral lobe in which the
mandibular laterosensory canal is located (=frenulum of Weber & de
Beaufort, 1916; Fig. 1A—C); no transverse postlabial groove sepa-
rating lower lip from gular region.

REMARKS. ‘The present diagnosis makes use of many oro-labial
features and excludes the subgenus Nukta from Schismatorhynchos.
Additional information on the oro-labial features is presented below,
with an explanation of our exclusion of Nukta.

Good series of small individuals are available for both new
species, making possible study of certain aspects of the late ontog-
eny of the mouth. Schismatorhynchos is a labeonin, as delimited by
Reid (1982, 1985). It appears to lack the superficial labial fold
anterior to the upper jaw that characterises a large subgroup of these
fishes, such as Garra, Epalzeorhynchos, Osteochilus, and Labeo. At
small size (< 30 mm SI) the upper lip is distinguishable as a ridge of
papillate tissue closely associated with the upper jaw. This ridge
thickens and becomes fully adnate to the upper jaw with growth, so
that by a size of 50 mm SI no distinction between the upper jaw and
upper lip is apparent, unlike members of the subgroup of labeonins,
such as Epalzeoprhynchos, with a scarcely developed, or regressed,
but nevertheless distinguishable superficial labial fold anterior to the
upper jaw. Thus, Schismatorhynchos appears to reside within a
relatively primitive assemblage of labeonin genera, which includes
Tylognathus (sensu Bleeker, 1963; Reid, 1985; p. 287) and Lobo-
cheilus, but for which relationships have yet to be worked out.

More clear is that the extremely elongate cutting edge of the lower
jaw, which results in the separation of the upper and lower lips
around the corner of the mouth, and the development of a lateral
frenulum are distinct specialisations within labeonins and unique
among cyprinids. These oro-labial specialisations of Schismato-

SCHISMATORHYNCHOS REVISION

99

Fig. 1 Outline drawings of oro-labial structure of: A. S. heterorhynchos, MZB unregistered, mm SI; B. S. holorhynchos, USNM 325389, 101.7 mm SI; C.
S. endecarhapis, MZB 6092, 179.0 mm SI; D. Lobocheilos bo, BMNH 1993.5.19:1, 87.0 mm SI; E. Tylognathus diplostomus, BMNH 1932.2.20:7, 215.0
mm SI. ELJ=edge of lower jaw; F=frenulum; LL=lower lip; M=mouth; MLL=median lobe lower lip; PG=postlabial grove; RC=rostral cap; UL=upper

lip.

rhynchos develop from structure general for labeonin cyprinids,
exemplified by Tylognathus diplostoma (Heckel, 1838)(Fig. 1E )
and similar to that of Tylognatus nukta (Hora, 1942: Fig. 9b; see
Reid, 1985:p. 287 for the assignment of Labeo nukta to Tylognathus).
At < 30 mm S| oro-labial structure of individuals of Schismato-
rhynchos is like that of T: diplostoma or T. nukta. At about 30 mm SL
the cutting edge of the lower jaw elongates, eventually interrupting
the connection between the upper and lower lips around the corner
of the mouth. At about the same time the fold in the skin which
separates the region of the mandibular laterosensory canal from the
rest lower labial tissue deepens, eventually forming the structure
Weber & de Beaufort (1916) referred to as the frenulum. Rather than
connecting the lower lip to the gular region, this frenulum houses the
mandibular laterosensory canal. As the cutting edge of the lower jaw
elongates, the portion of the lower lip between the lateral edge of the
lower lip and the principle lobe of the lower lip regresses, completely
in the two new species, nearly so in S. heterorhynchos.

Elongation of the cutting edge of the lower jaw progresses farther
in S. holorhynchos and S. heterorhynchos and their mouths are more
crescentic than that of S. endecarhapis; they are probably each
other’s closest relative.

Nukta Hora 1s considered by some recent authors to be a synonym
of Schismatorhynchos (Jayaram, 1981; Eschmeyer & Bailey, 1990;
Talwar & Jhingran, 1991). We do not agree with this assessment.
Instead we follow Reid (1985), insofar as his exclusion of Nukta from
Schismatorhynchos, and our diagnosis excludesNukta fro mSchismato-
rhynchos. Our reasons for supporting Reid are elaborated below.

Hora (1942) erected Nukta as a subgenus of Schismatorhynchos
for T. nukta (Sykes, 1841) in order to call attention to ‘the great
similarity in the form of [S. heterorhynchos and T. nukta]’, by which
he meant that both possess a deeply incised, heavily tuberculate
snout, the upper lobe of which forms a projection from between the
eyes. However, the outcome of the comparison between S.
heterorhynchos and T. nukta was not straitforward.

Whilst wishing to stress the similarity in the form of the snout
between the two species, Hora also recognised that they differ so
greatly in oro-labial structure that he also wrote ‘differences .. . in
the structure of the lips and associated structures are of sufficient
value to separate the two species generically’. Hora resolved the
dilemma between the similarity in the form of the snout and the
difference in oro-labial structure by subordinating Nukta under
Schismatorhynchos.

100

At the time Nukta was erected only S. heterorhynchos was known
and a direct comparison between it and T. nukta was logical. The
discovery of additional species with the oro-labial specialisations of
S. heterorhynchos complicates the issue. Hora’s phyletic association
focused on the remarkably modified snout found in each species but
the discovery of species of Schismatorhynchos with unmodified
snouts renders the association untenable because either the new
Schismatorhynchos species would have had to regress to an unmodi-
fied snout condition from the modified condition of S. heterorhynchos
and TZ. nukta or T. nukta would have had to regress to an unspecialised
oro-labial condition from the specialised condition of Schismato-
rhynchos. Either possibility is more complex, and therefore deemed
less likely, than the explanation required when justS. heterorhynchos
and T: nukta were known.

Hora, in making the comparison between S. heterorhynchos and
T. nukta, was, in part, acting on the suggestion by Weber & de
Beaufort (1916) that Schismatorhynchos might also be present on
the Indian subcontinent, though they presented no evidence to
support this suggestion. Hora’s comprehensive knowledge of the
Indian fish fauna led him to conclude that the only species Weber &
de Beaufort could possibly have been referring to was 7: nukta.
However, they may have been simply following Bleeker (1853,
1855), who noted in his description of S$. heterorhynchos that two
Indian species illustrated in Gray (1830, 1832) appeared to have
snouts similar in structure to the species he was describing. Bleeker
listed Cyprinus gotyla Gray, 1830 (=Garra gotyla) and Cyprinus
falcata Gray, 1832 (= ?Tylognathus falcatus; not Tylognathus
diplostomus (Heckel, 1838) nor T: dycocheilus (McClelland, 1839)).
The conclusion by Hora (1942:11) that Weber & de Beaufort could
only have been referring to 7? nukta may well have been mistaken,
and may have led to a comparison they, nor Bleeker, ever intended.

The discovery of two additional labeonin species with oro-labial
morphology like that of S. heterorhynchos demonstrates T. nukta is
not the closest relative of S. heterorhynchos. This and Bleeker’s
reference to the snout of species other than 7: nukta brings the
character of a divided snout into sharp focus.

A heavily tuberculate snout commonly occurs among labeonins,
as does the separation of the ethmoidal region from the premaxil-
lary—maxillary region by creases, folds, and indentations in the skin.
In some cases these are deep enough to ‘divide’ the snout. Since the
condition occurs widely, and sporadically among labeonins its status
as a synapomorphy in any particular case must be confirmed by
congruence with other characters. In the case of S$. heterorhynchos
and T. nukta the requirement of corroboration from additional
characters is not met. Rather, the oro-labial specialisations common
to all species of Schismatorhynchos suggest any resemblance between
the divided snout of S. heterorhynchos and T. nukta is one of
convergence, and therefore without taxonomic significance.

In summary, we support Reid’s exclusion of Nukta from
Schismatorhynchos for three reasons: the oro-labial specialisations
of Schismatorhynchos are unique among cyprinids; the ‘divided’
snout of S. heterorhynchos and T. nukta is not corroborated as a
useful indicator of relationship; and Hora was probably mistaken
when he assumed Bleeker and Weber & de Beaufort were suggesting
a comparison between S. heterorhynchos and T. nukta. Subordinat-
ing Nukta within Schismatorhynchos renders Schismatorhynchos
polyphyletic. Restricting Schismatorhynchos to Bleeker’s and We-
ber & de Beaufort’s concept of a group of labeonins with an elongate
lower jaw cutting edge which separates the upper lip from the lower
lips at the corner of the mouth, and also with a lower labial frenulum
which houses the mandubular laterosensory canal, exactly matches
Hora’s concept (1942:12—13) for the nominate subgenus Schismato-
rhynchos.

D.J. SIEBERT AND A.H. TIAKRAWIDJAJA
SPECIES ACCOUNTS

An account of each species of Schismatorhynchos is presented
below, and a comparative account for all three is given at the end of
the section.

Key to the species of Schismatorhynchos.

la. Snout with horizontal cleft, dark lateral band extends to the distal tips of
muddiercatidaltim=nay's---eeeracs eens cease eee S. heterorhynchos

1b. Snout without horizontal cleft, middle caudal fin-rays not pigmented

sncdurneventavefondenied toeeinvcasecursnaetaneersetuctesertrdstrcet nes tence =n eee Go to 2
2a. Dorsal fin branched ray count > 9 ................. S. endecarhapis sp. nov.
2b. Dorsal fin branched ray count < 10............. S. holorhynchos sp. nov.

Schismatorhynchos heterorhynchos (Bleeker, 1853)
(Figs 1A,2,3A,5)

Lobocheilos heterorhynchos Bleeker, 1853: 524.
Schismatorhynchos lobocheiloides Bleeker, 1855: 259.
Schismatorhynchus heterorhynchus Bleeker, 1863: 193.
Tylognathus heterorhynchos Gunther, 1867: 67.

SYNTYPE. BMNH 1866.5.2.82 (143.3 mm Sl), [Indonesia],
Sumatra, Solok, H.C. Schwanenfeld.

NON-TYPE MATERIALS. Sumatra—ZMA 115.911 (5, 175-228 mm
S]); [Indonesia]; Sumatra, Penetai, E. Jacobson, VII-1915. MZB
4818 (2, 119.6-156.6 mm Sl); Indonesia; Sumatra, Jambi Province;
Batang Hari basin, Sungai Meringin at Muaraimat; col. Suroto and
M. Siluba; 16-VIII-1982.

Borneo (Kapuas River basin, Kalimantan Barat, Indonesia) —
MZB 5456 (2; 67.9-71.2 mm SI), Sungai Kapuas at Putussibau, col.
Munandar, 26-IV-1983. Upper part of Sungai Sibau, col. Ike
Ratchmatica and Haryono, 25 June—7 July 1996: 1) MZB 8600,
Station IV (1, 98.8 mm S1); 2) MZB 8601, Station IV, Habitat 2 (1,
110.4 mm S1); 3) MZB 8602, Station VI.2 (2, 86.9-97.6 mm Sl); 4)
MZB 8603, Station IX, at Muara Suluk (1, 134.0 mm SI); 5) MZB
8604, Station XIII (5, 85.4-93.8 mm S]); and 6) MZB 8605, Station
XIV, at Muara Apeang (1, 101.7 mm Sl). Sungai Putan, an upper
basin tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono;
22-26 Jun 1996: 1) MZB 8606, Station III (2, 91.7—93.3 mm SI); 2)
MZB 8607, Station IV (1, 106.6 mm S]); 3) MZB 8608, Station V (1,
107.3 mm SI); 4) MZB 869, Station VIII (2, 89.4-96.0 mm S]); and
5) MZB 8610, Station VI (1; 92.2 mm S1). Sungai Apeang, an upper
basin tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono;
30 Jun 1996: 1) MZB 8611, Station X.2 (2, 98.6—128.2 mm Sl); and
2) MZB 8612, Station X.4 (2, 104.8-136.9 mm SI). SungaiAring, an
upper basin tributray of Sungai Sibau; col. Ike Ratchmatica and
Haryono; 7 Jul 1996: 1) MZB 8613, Station XVI (1, 96.2 mm Sl);
and 2) MZB 8614, Station XVI.2 (3, 97.2-131.0 mm Sl). Sungai
Menjakan, an upper basin tributary of Sungai Sibau; col. Ike
Ratchmatica and Haryono, | Jul 1996: 1) MZB 8615, Station XI.1
(1, 132.6 mm SI); and 2) MZB 8616, Station X1.3 (1, 81.4 mm Sl).
Sungai Sekedam Besar, an upper basin triburaty of Sungai Sibau:
col. Ike Ratchmatica and Haryono; 25 June 1996, MZB 8617,
Station II (3, 09.1-97.6 mm Sl). Sungai Berarap, an upper basin
tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 3 Jul
1996; MZB 8618, (1, 95.0 mm Sl).

DIAGNOSIS. A species of Schismatorhynchos with a deep horizon-
tal cleft in snout (S. holorhynchos and S. endecarhapis without cleft
in snout); snout, including cleft, heavily tuberculate, tubercles pyra-

SCHISMATORHYNCHOS REVISION

_ ae
Me ee i

be

Fig. 2 Photograph of a large (A. ZMA 115.911, 224 mm SI), medium (B. syntype, BMNH 1866.5.2.82, 143.3 mm SI), and small (C. MZB 5456, 68.8

mm SI) specimens of S. heterorhynchos.

midal, large, unicuspid (S. holorhynchos with coni
date tubercles; S$. endecarhapis

dorsal fin with eight branched fin-ray
ple fin-rays very elongate in larger individuals (S$. endecarhapis with
11 branched rays in dorsal fin); distinct, dark lateral band extending
to distal tips of middle rays of caudal fin (lateral band of S. holo-

al, multi-cuspi-
simple, conical tubercles);
falcate, anterior two princi-

rhynchos and S. endecarhapis not extending onto caudal fin-rays).

DESCRIPTION. Material in a 70-225 mm S] size range was avail-
able for study. No material was available below 68 mm Sl] and the
five largest specimens are not in good condition. They are old,
poorly preserved, and flattened, limiting study of shape change in

102

D.J. SIEBERT AND A.H. TJAKRAWIDJAJA

Fig. 3 Snout tubercles of: A. S. heterorhynchos, MZB 8612, 136.4 mm Sl]; B. S. holorhynchos, FANH 68550, 77.6 mm Sl; C. S. endecarhapis, MZB

6092, 179.0 mm SI.

this species, which appears considerable. A photograph of a small,
medium and large specimen is presented in Figure 2. Selected
morphometric ratios, meristic information, and vertebral counts are
reported in Tables 1-3.

Head relatively long, with a comparatively small eye, increased
head length due to an elongate, pointed snout with a well developed
rostral fold (=rostral cap of Roberts, 1989) which is hypertrophied in
support of heavy tuberculation. Snout divided by a deep horizontal
cleft above Ist infraorbital bone (Io 1). Upper (ethmoidal) lobe
consists of connective tissue outgrowth from front edge of
mesethmoid, supports large tubercles; in dorsal view its anterior
edge indented in midline to form left and right anterior lobes.
Anterior extension of rostral cap also consists of a connective mass
which supports anterior tubercles of snout. Two pairs of barbels
present, anterior pair small, posterior pair longer, but hidden in a
deep recess at corner of mouth.

Mouth inferior, broad, C-shaped, usually a little wider than long
(mean Mw:MI1 = 1.3; range = 0.9-1.6., SE= 0.05, n=32). Lower jaw
equipped with an emergent, thin, flexible, extremely long cornified
cutting edge which is much longer than posterior extent of upper and
lower lips. Posterior tips of cutting edge of lower jaw extend behind
a vertical line from middle of eye.

Large, unicuspid, pyramidal tubercles, with 3—5 sides, present in
and around rostral cleft (Fig. 3A). Tubercles also present around
dorsal edges of upper lobe of snout formed by rostral cleft, on upper
and lower interior surfaces of rostral cleft, between eye and nares, on
upper half of Io 1, and over dorsal and anterior aspects of rostral cap.
Large tubercles absent from dorsal surface of head except for those
found at dorsal edges of upper lobe of snout.

Shape of S. heterorhynchos changes with size (Fig. 2). Smallest

specimens examined have a relatively round body. Between 100 mm
Sl and 150 mm S] body depth and compression increases. Above 170
mm Sl] body shape is deep and decidedly compressed.

Dorsal fin falcate, with first two principal fin-rays greatly elon-
gated in large individuals, when depressed extending beyond anal-fin
origin to more than mid-way along caudal peduncle. Dorsal fin
height nearly 50% of SL in largest individuals examined. Increase in
length of first two principal dorsal-fin rays strongly allometric with
respect to Sl, with allometric coefficient much greater than unity
(Fig. 4). Pectoral fin of large individuals slightly longer than head
length, but in small individuals much shorter than head length.
Pelvic fin inserted behind dorsal-fin origin, at 4th branched ray of
dorsal fin.

Lateral line usually with 31 or 32 scales (Table 2) to end of
hypural plate, slightly curved, running in middle of caudal peduncle
posteriorly; 5% scales above lateral line to dorsal origin; 4% scales
below lateral line. All specimens examined with 31 vertebrae,
usually with 15 precaudal vertebrae and 16 caudal vertebrae (Table
3). Number of pairs of pleural ribs usually 12.

In alcohol dorsum dark, with ventral half of body creamy. A wide,
dark lateral band present, centred on lateral line, beginning at
operculum and extending to distal tips of middle rays of caudal fin.
Upper anterior corner of lateral stripe, where it meets hind edge of
operculum, intensified to form a dark mark, prominent in smaller
individuals but less so in larger individuals. Lateral band two scale
rows wide, includes lower % of scale row above lateral line scale row
and upper % of scale row below lateral line scale row. Lateral band
may be evident only on the posterior half of the body on large
individuals. Dorsal, pectoral, pelvic, anal, and upper and lower lobes
of caudal fin clear.

Table 1 Selected morphometric variables for species of Schismatorhynchos;, the mean is followed (+) by the standard deviation; the range is reported as
the minimum and maximum observation; sample size is reported in column headings.

S. heterorhynchos n=38

S. holorhynchos n=8 1 S. endecarhapis n=19

Head length
Snout length

Eye length (%HL)
Eye length
Predorsal length
Body depth

Caudal peduncle depth
Dorsal-fin base length

26.6+1.4 22.6-28.9
12.5+1.1 10.8-14.2
18.6+1.8 13.5—20.8
4.9+0.6 3.4— 6.0
47.6+1.5 43.6-50.4
27.0+2.9 21.9-35.6
12.4+1.0 11.0-15.4
17.7+1.6 12.4—22.3

25.4+1.2 21.5—27.7
9.6+1.0 6.9-11.2
22.3+2.8 17.7-28.8
5.940.8 4.4— 7.4
47.8+2.2 39.2-52.8
27.5+1.7 23.0-30.5
12.8+0.6 11.2-13.8
16.141.1 12.4-18.9

24.5+1.4 20.5-27.0

8.740.9 6.9-10.2
23.1+3.4 18.3-30.8

5.741.0 4.1- 7.7
47.7+1.4 45.5-5S0.2
25.0+1.9 21.4-28.6
11.1+0.5 10.2-12.2
24.6+1.8 22.4-29.3

SCHISMATORHYNCHOS REVISION

Table 2 Lateral line scale count frequencies for species of
Schismatorhynchos.

30 31 32 33 34
S. heterorhynchos 4 12 18 4
S. holorhynchos 4 50 2) 3

S. endecarhapis 3 13 3

DISTRIBUTION. Studied material of S. heterorhynchos originates
from three localities on Sumatra and from the Kapuas River basin,
Kalimantan Barat, Borneo (Fig. 5). We consider only the two most
recent reported Sumatra localities to be verifiable. Solok is reported
as the type locality of the species (Bleeker, 1853), but we are not
confident the types actually originate from there. Solok is located in
the very upper reaches of the Indragir River basin Sumatera Barat
Province, just north of the Batang Hari basin and on the overland
route between the cities of Jambi, Jambi Province and Padan,
Sumatera Barat Provence. Much of this route is in the Batang Hari
basin and it is quite possible the material Bleeker listed as coming
from Solok was actually collected along the route to Solok and
within the Batang Hari basin. Within the Kapuas River basin verified
localities at which S. heterorhynchos has been captured are all
within the Sungai Sibau basin. Schismatorhynchos heterorhynchos
has been collected only from the upper parts of river basins, near to
or in foothill regions, both on Sumatra and Borneo. These parts of
river basins are among the least well collected and further explora-
tion of these habitats may reveal the species to be quite widespread.

4a
ot

Qt
94

°

103

* LNSL °

Fig. 4 Log-log plot (natural logarithms) of the relationship between
height of the dorsal fin and standard length; # = S. heterorhynchos,
LnDFI = -3.2 + 1.44LnSI, SE of coefficient = 0.05, R* = 0.96, n = 36;
A = S. endecarhapis, LnDfl = —-1.7 + 1.09LnSI, SE of coefficient =
0.07, R? = 0.92, n = 25; and @ = S. holorhynchos, LnDfl = -1.9 +
1.12LnSIl, SE of coefficient = 0.04, R* = 0.99, n= 13.

121°
+9°

Fig. 5 Localities from which Schismatorhychos material was examined in this study; # = S. heterorhynchos, & = S. endecarhapis, and

@ = S. holorhynchos; target symbols = type localities.

104

REMARKS. Sumatra materials appear to have a more rounded head,
deeper body, and longer fins than specimens from Borneo. We
attribute this to larger size of the Sumatra specimens studied, but
further materials in the appropriate size range (smaller specimens
from Sumatra and larger specimens from Borneo) may reveal the
two populations to be different species. If so, a new name will be
required for the Kapuas River species.

Schismatorhynchos holorhynchos sp. nov. (Figs 1B,3,5,6)
Schismatorhynchus heterorhynchus; Inger & Chin, 1962: 86

HOLOTYPE. USNM 325389 (101.7 mm Sl); Malaysia; Sarawak;
confluence of Batang Balui and Batang Kerumo; O2°22'N 113°45'E;
col. L. Parenti, K. Luhat, and A. Among; 3-VII-1991; field no. LRP
91-28.

PARATYPES. USNM 346637 (12 including | cleared and counter
stained, 39.5—78.8 mm Sl); data as for holotype.

NON-TYPE MATERIALS. Borneo (Kinabatangan River basin, Sabah,
Malaysia) - FMMN 68548 (28, 28.3—34.8 mm Sl); small stream 1
mi. above Sungei Tabalin Besar, Sta. 1; col. R. Inger and P.K. Chin;
21 April 1956. FMNH 68549 (1, 49.3 mm SI); Deramakot Camp, hill

D.J. SIEBERT AND A.H. TJAKRAWIDJAJA

stream; col. R. Inger; 2 May 1956. FMNH 68550 (5, 42.7-79.3 mm
S1); Deramakot Camp, hill stream below waterfall; col. R. Inger and
P.K. Chin; 2 May 1956. FMNH 68551 (1, 47.8 mm SI); Deramakot
Camp, stream below water fall; col. R. Inger; 3 May 1956. FMNH
68552 (30 of 147, 30.3-49.4 mm Sl); Deramakot Camp; col. R.
Inger and P.K. Chin; 8 May 1956. FMNH 94183 (1, 55.8 mm SI);
Deramakot Camp, hill stream; col. R. Inger; 2 May 1956.

Borneo (Rejang River basin, Sarawrak, Malaysia) - USNM
325359 (2, 21.8-55.8 mm Sl); Baleh River, creek entering northern
bank approx 5 km E of Sut River; 2°2'N 113°07'E; col. L. Parenti et
al.; 25 Jul 1991. USNM 324978 (2, 33.5—35.5 mm S]); Baleh River,
stream entering river opposite Sekolah Negara Bawai; 2°0'N
113°03'E; col. L. Parenti et al.; 24 Jul 1991. USNM 325387 (2, 59.2—
59.5 mm S]); Baleh River, creek entering southern bank approx. 20
km E of Sut River; 2°01'N 113°06'E; col. L. Parenti et al.; 24 Jul
1991. USNM 325388 (2, 67.6-68.7 mm S1); Batang Balui, Batang
Tamn were it enters Bantan Balui; 02°22'N 113°47'E; col. L. Parenti
et al.; 6 Aug 1991. USNM 325390 (18, 36.2—77.2); Batang Balui,
Batang Lut at Batang Balui; 2°22N 113°46'E; col. L. Parenti et al.; 3
Aug 1991. USNM 325411 (28, 38.7-77.6 mm Sl); Batang Balui,
stream near mouth; 2°20'N 113°49'E; L. Parenti et al.; 6 Aug 1991.

DIAGNOSIS.

A species of Schismatorhynchos with eight branched

Fig. 6 Photographs of the holotype (A. USNM 325389, 101.7 mm Sl) and a small (B. USNM 325890, 43.6 mm SL) specimen of S. holorhynchos.

SCHISMATORHYNCHOS REVISION

105

Table 3 Vertebrae, branched rays in dorsal fin, and pairs of pleural ribs counts for species of Schismatorhynchos; the mean is followed (+) by the standard
deviation; the range is reported as the minimum and maximum observations; sample size is reported in the column heading.

S. heterorhynchos n=38

S. holorhynchos n=99 S. endecarhapis n=45

Vertebrae 31+0.0

Precaudal vertebrae 15.94+0.23 15-16
Caudal vertebrae 15.1+0.23 15-16
Peduncular vertebrae 5.4+0.50 5— 6
Dorsal fin position 8.0+0.23 7- 9

18.9+0.23 18-19

32.0+0.10 31-32

33.040.15 32-33

Anal fin position
Branched dorsal-fin rays 8+0.0
Ribs 12.3+0.47 12-13

rays in dorsal fin (S. endecarhapis with 11 branched rays in dorsal
fin); snout pointed, without cleft (S. heterorhynchos with deep cleft
in snout), tuberculate, tubercles conical, becoming multicuspid to
stellate in individuals about 60 mm SL and greater (S. heterorhynchos
with pyramidal tubercles; S$. endecarhapis with simple, conical
tubercles); a round blotch on caudal peduncle (S. heterorhynchos
and S. endecarhapis without round blotch on caudal peduncle).

DESCRIPTION. The largest specimen available for study is about
102 mm SI, however the species grows considerably larger in Sungai
Sebangu (K.Martin-Smith, pers. comm.) The overall form of the
body is shown in Figure 6. Selected morphometric ratios, meristic
information, and vertebral counts are reported in Tables 1-3.

Snout pointed, tuberculate, tubercles moderate in size, absent
from region of the cleft in snout of S. heterorhynchos. Two pairs of
barbels, anterior pair small and fitting in grove, posterior pair hidden
in deep recess at mouth corner.

Mouth C-shaped, usually distinctly wider than long (mean Mw:MI
= 1.8. range 1.3—2.2, SE 0.07, n=10). Cutting edge of lower jaw
emergent, its tips extend posteriorly to vertical line from anterior
margin of pupil. Lateral lobe of lower lip thick.

Snout and dorsal surface of head posterior to nares and body
anterior to dorsal fin tuberculate. Snout heavily tuberculate. Tuber-
cles in region of snout well-developed, conical, multicuspidate in
larger specimens (Fig. 3B) but simple in specimens less than about
60 mm SL. Rostral tubercles present laterally on first infraorbital (Lo
1), around tip of snout, over dorsal surface of tip of snout, between
nares, and between nares and eye. Tubercles absent from a patch
between front edge of ethmoid and anterior part of snout that
corresponds in position to the deep cleft in snout of S. heterorhynchos
(Inger and Chin, 1962). Region between dorsal fin and nares covered
by numerous fine tubercles.

Dorsal fin origin in advance of pelvic fin, margin slightly convex.
Pelvic fin origin at 3rd branched ray of dorsal fin. Pectoral fin less
than head length. Caudal fin forked.

Lateral line complete, slightly curved, running in the middle of
caudal peduncle posteriorly, usually with 31 scales to end of hypural
plate (Table 2), 5% scales above lateral line to dorsal origin; 44%
scales below lateral line. Vertebrae usually 32, usually with 16
precaudal and caudal vertebrae. Number pairs of pleural ribs usually
10 or 11.

In alcohol dark from above, creamy below. Indistinct, dark, lateral
band present, its origin before origin of dorsal fin. Band width
equivalent to width of one scale row, anteriorly lateral band lies
above lateral line, posteriorly lateral band lies over lateral line.
Precaudal spot present, very distinct in small individuals, larger but
may be obscure in larger individuals. Side of body above middle of
pectoral fin with a few scales darkly marked.

ETYMOLOGY. The name holorhynchos is from the Greek words
holos, meaning whole or entire, and rhynchos, meaning snout. It is

16.0+0.17 15-16 16.9+0.32 16-17
16.0+0.14 16-17 16.1+0.36 15-17
5.8+40.48 5-7 5.8+0.44 5-6
7.9+0.30 7— 8 8.0+0.0

19.0+0.46 19-20 20.1+0.32 20-21
8.0+0.10 7- 8 11.0+0.40 10-12
10.3+0.51 9-11 12.7+0.45 12-13

in reference to the new species’ snout, which lacks the deep cleft
found in the snout of its sister species, S. heterorhynchos.

DISTRIBUTION. Materials of S. holorhynchos originate from within
the Rejang River basin, Sarawak, Malaysia and the Kinabatangan
River basin, Sabah (North Borneo), Malaysia (Fig. 5). The species
has also been collected to the south of the Kinabatangan River, in the
Segama River basin in Sabah (K.Martin-Smith pers. com.). The
Sarawak and Sabah localities from which S. holorhynchos has been
taken are distant from one another and the Rejang and Kinabantangan
rivers which it is know to inhabit flow off Borneo in different
directions and into different seas. It would be remarkable if S.
holorhynchos was discovered not to inhabit some of the many river
basins lying between the two rivers from which it has been collected.

Schismatorhynchos endecarhapis sp. nov. (Figs 1C,3,5,7)
Schismatorhynchos heterorhynchos, Roberts, 1989: 79, Fig. 58.

HOLOTYPE. MZB 6092 (179.0 mm SL): Indonesia; Kalimantan
Tengah; Barito River drainage; Sungai Laung at Desa Maruwei
(0°21.986'S 114°44.103'E); hook and line; col. D.J. Siebert, A.H.
Tjakrawidjaja and O. Crimmen; 15-18 Jul 1992; field no. DS-12-
L992:

PARATYPES. BMNH 1993.5.12:1-19 (19, 61.9-41.8 mm S); Indo-
nesia; Kalimantan Tengah; Barito River basin; mouth of small
stream at Project Barito Ulu base camp on Sungai Busang; seine;
col. D.J. Siebert, A.H. Tjakrawidjaja and O. Crimmen; 27-28 Jan
1991; field no. 3-DJS-1991. MZB 3434 (1, 88 mm Sl); Indonesia;
Kalimantan Barat; Kapuas River basin; rocky channel in main-
stream of Sungai Pinoh at Naga Saian, 45 km S of Nagapinoh;
0°43'S 111°38.5'E); rotenone; col.T.R. Roberts and S. Wirjoatmodjo;
26 Jul 1976; field no. Kapuas 1976-29.

NON-TYPE MATERIALS. Borneo (Barito River basin, Kalimantan
Tengah, Indonesia) - BMNH 1993.5.12:52—61 (10, 43.3—22.3 mm
Sl); sand bars of Sungai Joloi above its confluence with Sungai
Busang; seine; col. D.J. Siebert, A.H. Tjakrawidjaja and O. Crimmen;
8 Feb 1991; field no. 13-DJS-1991. BMNH 1993.5.12:62-74 (13,
48.0-26.5 mm Sl); sand bars of Sungai Murung around Project
Barito Ulu base camp on Murung River; seine; col. D.J. Siebert,
A.H. Tjakrawidjaja and O. Crimmen; 12 Feb 1991; field no. 16-
DJS-1991. BMNH 1993.5.31-51 (21, 48.2-19.4 mm Sl); Barito
River at Desa Muara Laung; 0°34.576'S 114° 44.205'E; seine; D.J.
Siebert, A.H. Tjakrawidjaja and O. Crimmen; 20-22 Feb 1991; field
no. 22-DJS-1991. BMNH 1993.5.12:20-30 (11, 46.7-34.4 mm S);
sand bars of Sungai Busang at Project Barito Ulu base camp on
Sungai Busang; seine; D.J. Siebert, A.H. Tjakrawidjaja, O. Crimmen;
14-15 Feb 1991; field no. 18-DJS-1991.

Borneo (Kapuas River basin, Kalimantan Barat, Indonesia) —
MZB 3434 (1, 88 mm SI); Sungai Pinoh at Naga Saian; O°43'S

106

D.J. SIEBERT AND A.H. TJAKRAWIDJAJA

Fig. 7 Schismatorhynchos endecarhapis: A. MZB 6092, holotype, 179.0 mm SI; B. S. endecarhapis, BMNH 1993.5.12:1—19, paratype, juvenile, 59.4 mm

SI.

111°38.5'E; rotenone; T.R. Roberts; 26 July 1976; field no. Kapuas
1976-29. MZB 3433 (2); Sungai Pinoh 37 km S of Nagapinoh;
0°39.5'S 111°40'E; rotenone; T.R. Roberts; 24 July 1976; field no.
Kapuas 1976-27.

DIAGNOSIS. A species of Schismatorhynchos with 11 branched rays
in dorsal fin (S. heterorhynchos and S. holorhynchos with eight
branched rays in dorsal fin); snout entire (S. heterorhynchos with
cleft snout); tubercles conical, simple (S. heterorhynchos with py-
ramidal tubercles, S$. holorhynchos with multicuspid tubercles);
gape not reaching vertical from anterior margin of eye (S.
heterorhynchos and S. holorhynchos with gape reaching to beyond
anterior margin of eye); modally 33 pored lateral line scales (S.
heterorhynchos usually with 31—32 pored lateral line scales, S.
holorhynchos usually with 31 pored lateral line scales).

DESCRIPTION. Material available for study consists of small speci-
mens and one larger individual (holotype). The gap in size between
the largest of the smaller material and the holotype is so large that
study of allometry and shape change with size is not feasible. The
overall form of Schismatorhynchos endecarhapis is shown in Figure
7. Selected meristic, morphometric, and vertebral data are presented
in Tables 1-3.

Head length moderate (Table 1); gape reaching to a little before
anterior margin of eye; snout with well developed rostral cap. Two
pairs of barbels, anterior barbel in grove on snout, shorter than
posterior barbel; posterior barbel about equal to eye diameter.

Mouth crescentic, more than twice as wide as long (mean Mw:M1
= 2.4; range 2.2—2.8; SE 0.08; n=9). Upper lip well separated from
rostral cap, not continuous with lower lip around corner of mouth.
Lower jaw with a sharp horny covering. Median lobe of lower lip
wide, covering most of lower jaw, continuous with isthmus, sepa-
rated from well developed lateral lobes of lower lip by a deep post
labial grove.

Only a single large specimen of this species is known; observa-
tions of the extent of tuberculation are thus limited in scope. Small
individuals with a few small tubercles, large individual with many
small tubercles. Snout tuberculate, a small patch of large, unicuspid,
conical tubercles present just above and before rostral barbel (Fig.
3C). Smaller tubercles present around anterior face of rostral cap.
No large tubercles on Jo | nor in space between nares and eyes. Fine
tubercles present over dorsal surface of head but appear to be absent
between nape and dorsal fin.

Dorsal fin long, with 11 branched fin-rays (1 individual with 10,
1 individual with 12), origin well in advance of pelvic fins. Margin

SCHISMATORHYNCHOS REVISION

of dorsal fin falciform, first few anterior principal rays long. Caudal
fin forked.

Lateral line nearly straight, with 33 scales to end of hypural plate;
5 Yascales above lateral line to dorsal origin; 4/2 scales below lateral
line. Vertebrae usually 33 (2 of 35 individuals with 32), usually with
17 precaudal vertebrae and 16 caudal vertebrae. Number of pairs of
pleural ribs usually 13.

Colour in alcohol dark above, lighter below (Fig. 7). Scale
pockets of scale rows to at least 2 scales rows below lateral line with
a distinct, dark crescent. A dark lateral stripe evident, terminating in
a distinctly triangular precaudal spot. In larger individuals stripe
consists of coloration centred over 3 scale rows; stripe on lateral line
scale row begins below posterior end of dorsal fin, on Ist scale row
above lateral line stripe beings at dorsal origin and ends at precaudal
spot, on 2nd scale row above lateral line stripe begins midway
between occiput and dorsal origin and ends midway along peduncle;
in small individuals stripe evident on lateral line scale row only.
Small individuals with a prominent mark on side at 5th or 6th scale
along lateral line (Fig. 1b), usually a scale above and below lateral
line darkened along with | or 2 scales on lateral line. Dorsal and
caudal fins dusky, interradial membranes heavily marked with
melanophores. Interradial membranes of pectoral and pelvic fins
lightly marked with melanophores.

ETYMOLOGY. The species name endecarhapis is formed from the
Greek words endeka (eleven) and rhapis (rod), referring to the
modal number (11) of branched rays in dorsal fin. It is proposed as
a noun in apposition.

DISTRIBUTION. Schismatorhynchos endecarhapis is known from
the Barito River above Muara Teweh and from Sungai Pinoh of the
Kapuas River system (Fig. 5). Whether or not the species occurs in
the lower reaches of these watersheds where streams are larger is not
yet known. In the Barito small individuals were seined at creek
mouths and on sand bars along the mainstream.

REMARKS. The largest individual was taken by hook and line,
baited with beetle larvae, below floating houses at Desa Maruwei,
indicating that the species is an opportunistic feeder even though the
length of its intestine would indicate it is predominately a herbivore.

Intrageneric comparisons

Species of Schismatorhynchos are easily distinguished from one
another and gross differences are employed in the key to species.
The meristic information of Table 3 is summarised graphically in
Figure 8. Axis 1, which can be interpreted as an axis of dorsal fin
branched ray and caudal vertebrae counts, provides a dimension
along which S. endecarhapis is clearly separable from S. hetero-
rhynchos and S. holorhynchos. Axis 2, interpreted as an axis of
overall vertebral pattern and rib count, separates S. hetero-
rhynchos and S. holorhynchos. Figure 9 summarises the morpho-
metric information of Table 1. Complete separation of the three
species is achieved in the two dimensions of Axis | and Axis 2.
Axis | is interpreted as a head length/dorsal-fin base length axis.
Axis 2 is a contrast of dorsal-fin base length and caudal peduncle
depth.

TUBERCULATION PATTERNS. Species specific tubercle distribution
patterns in Schismatorhynchos are evident at small size. The regions
of the snout which will eventually contain large tubercles are
apparent at sizes smaller than 30 mm SL in S. endecarhapis. and
S. holorhynchos, well before the tubercles undergo obvious enlarge-
ment.

107

-14 -9 1 6

-4
AXIS 1
Fig. 8 Graphical joint summary of the meristic information for species of
Schismatorhynchos with 0.95 confidence ellipses of samples
(S. heterorhynchos = ; S. holorhynchos = @; S. endecarhapis = A).
Standardised discriminant function for: Axis | = 0.03 x anal fin position
+ 0.26 x peduncular vertebrae count — 1.68 x caudal vertebrae count —
1.49 x precaudal vertebrae count — 0.09 x rib count — 0.04 dorsal fin
position — 0.75 x number of branched rays in dorsal fin; Axis 2 = 0.01 x
anal fin position + 1.32 x caudal vertebrae count + 0.05 x peduncular
vertebrae count + 1.23 x precaudal vertebrae count — 0.57 x rib count —

0.03 x dorsal fin position — 0.49 x number of branched rays in dorsal
fin; Wilk’s lambda = 0.001, df 7,2,173, p < 0.0001.

5.

2.4

AXIS 2

“8.050

-2.8
AXIS 1

-5.4 -0.2 2.4 5.0

Fig.9 Graphical joint summary of the selected morphometrics of species
of Schismatorhynchos with 0.75 confidence ellipses of samples
(S. heterorhynchos = @; S. holorhynchos = @; S. endecarhapis = A).
Standardised discriminant function for: Axis 1 = 2.39 x body depth + 2.01
x dorsal base + 1.55 x predorsal length — 1.21 caudal peduncle depth —
0.49 x eye length — 3.77 x head length — 0.88 x snout length; Axis 2 = 0.98
x body depth + 4.90 x caudal peduncle depth + 0.85 x eye length + 0.74 x
predorsal length — 5.28 x dorsal base — 1.40 x head length — 0.91 x snout
length; Wilk’s lambda = 0.04, df 7,2,229, p < 0.0001.

108

DISCUSSION

Including Schismatorhynchos endecarhapis and S. holorhynchos in
the genus Schismatorhynchos raises a number of theoretical and
practical problems, as would including them in the obvious alternat-
ive, Lobocheilos. Bleeker’s (1863) diagnosis of Schismatorhynchos
includes, among other things, mention of a deep, transverse cleft of
the snout and the upper and lower lips not continuous around the
corner of the mouth. Weber & de Beaufort (1916; Fig. 86) described
an additional oro-labial structure of Schismatorhynchos, a frenulum
between the lateral lobe of the lower lip and the isthmus (Fig. 2A).
Hindsight shows that the cleft snout is characteristic, so far as is
known, of a single species (S$. hetero-rhynchos) while the oro-labial
features are found in at least two additional species. Our decision to
include the new species in Schismatorhynchos rests on these oro-
labial features, which we consider derived for Southeast Asian
labeonins (we recognise them as synapomorphies of the genus
Schismatorhynchos).

The problem, and it is nothing more than that of including
additional species in any monotypic genus with a very specific,
highly descriptive name, of including the two new species in
Schismatorhynchos 1s that both lack a cleft in the snout. However,
the problem is not so much that the two new species lack a cleft snout
but that the highly descriptive generic name Schismatorhynchos is
apt for only one species of the genus. Generic names serve two
functions in modern classification: 1) the first element of a unique
binomen; and 2) the name of a group of species that are close
phylogenetic relatives of each other. The first function is a matter of
nomenclature. The second function lies within the realm of the
science of Systematics and we believe it to be of greater importance.
Since there is good evidence (the oro-labial features) that the two
new species are close relatives of S. heterorhynchos we include them
in Schismatorhynchos even though they lack a cleft snout. This
leaves the name Schismatorhynchos apt for only one of the three
species in the genus but we do not see this as reason enough to
propose a new generic name for the other two, especially since S.
holorhynchos 1s probably more closely related to S$. heterorhynchos
than it is to §. endecarhapis.

Lobocheilos is herein recognised as that group of Southeast Asian
cyprinids possessing a very wide median lobe of the lower lip and
with the lower and upper lips continuous around the corner of the
mouth (Fig. 1D). This definition conforms to that of Smith (1945),
who followed de Beaufort’s (1927) comment on an Indo-Australian
subgroup of Tylognathus Heckel. The two new species of
Schismatorhynchos could have been assigned to Lobocheilos, as lip
structure (generally) and scale and vertebral counts of the new
species of Schismatorhynchos do conform to those of species of
Lobocheilos. Some may prefer such an assignment, especially since
the new species lack a rostral cleft, but to do so on the basis of the
absence of a rostral cleft ignores the two derived oro-labial charac-
ters which all species of Schismatorhynchos share. As we pointed
out above, we choose to focus on the evidence that the two new
species are closely related to S$. heterorhynchos rather than their lack
of a cleft in the snout.

A more practical problem is that Schismatorhynchos
endecarhapis will not key to genus using any regional key in
general use of which we are aware (Weber and de Beaufort, 1916;
Smith, 1945; Inger and Chin, 1962; Kottelat et al., 1993). The
initial problem encountered in these keys is the count of branched
rays in the dorsal fin. Schismatorhynchos heterorhynchos Bleeker,
S. holorhynchos, and members of the closely related genus
Lobocheilos possess fewer than 10, usually only eight, branched

D.J. SIEBERT AND A.H. TJAKRAWIDJAJA

rays in the dorsal fin. Schismatorhynchos endecarhapis, with 11
branched rays in the dorsal fin, fails this distinction, instead fall-
ing into Tylognathus, Labeo, or Cirrhinus (depending on which
key is used).

The second problem is that a deep rostral cleft is used to separate
Schismatorhynchos andLobocheilos. Both new species of Schismato-
rhynchos fail this distinction. However, to our. knowledge, the
characters of upper and lower lips not continuous around the corner
of the mouth and presence of a frenulum between the lower lip and
the isthmus always separates Lobocheilos and Schismatorhynchos
correctly.

Annotations to keys to cyprinid genera of the
region.

We suggest the following annotation to the Cyprininae key of Weber
& de Beaufort (1916; p. 94):

1. Suborbital bone covering greatest part of cheek; lower jaw with sym-
physial tubercle; the broadly reflected lower lip not separated from jaw
Hose Soon sty az vntis sus ose REE ataa taeda? au Coa aoe o oO cae Barbichthys

2. Ring of suborbital bones not enlarged, lower jaw without symphysial
tubercle; lower lip distinct from lower jaw.

a. lower and upper lips not continuous around the corner of the jaw

wei aries Sie once cPuswenaazen tent tadsancenes omen aad Schismatorhynchos
b. lower and upper lips continuous around corner of lower jaw.

aa. Dorsal with 10-18 branched ray .............--.2sccesccereeeeeeeeees Labeo

bb. Dorsal with 8—9 branched rayS .............:ceceeeeereees Lobocheilos

The key to genera of Cyprinidae of Kottelat, et al (1993;p. 29) can
accommodate an expanded Schismatorhynchos with the following
modifications (which make couplet 30 unnecessary).

27a. Suborbital bones enlarged and covering most of cheek (Fig. 109); lower
jaw with a symphysal knob; lower lip reflected backwards,but not
Separated MOMa AW: ccs: c.ccssece eset sanewarsm sens coon voese eee Barbichthys

27b. Suborbital bones not enlarged; no symphysial knob on lower jaw; lower
lip distinctly separated from loWer Jaw ............-csscecesceereeeeeseees go to *

*a. lower and upper lips not continuous around corner of lower jaw
sbaie ad dates dbeasv tee tec degen eit Re Schismatorhynchos

adele sade Salea Peat ds oate deeb awa aysoee eaten aaiaees saxtcrepeee tN eats sare go to 28
28a. 10-18 % branched dorsal rays ................::c+0s00+ go to 29
28b. 8-9 ¥2 branched dorsal rays .........-..::eseeeeee Lobocheilos

ACKNOWLEDGEMENTS. Many institutions and individuals contributed to
make our survey efforts in the Barito River possible. The Indonesian Insti-
tute of Sciences (LIPI) granted permission to conduct research in
Kalimantan; the Natural History Museum and the Research and Develop-
ment Centre for Biology (PPPB), Bogor allowed the authors to make this
effort The Worshipful Fishmongers Co., London provided a generous
grant to fund the second expedition; the Royal Society, London, the
Godman Fund for Exploration, London, the Natural History Museum,
London, and the National Museum of Natural History, Washington, D.C.
all contributed toward the first expedition. Project Barito Ulu provided
invaluable logistic and other support for the first expedition. The Sumanti
family of Desa Maruwei, Kalimantan Tengah provided gracious hospital-
ity, without which the holotype would never have been obtained. Rony
Huys is thanked for translation of old Dutch.

SCHISMATORHYNCHOS REVISION

REFERENCES

de Beaufort, L.F. 1927. Description of a new cyprinoid fish from Siam. Journal of the
Siam Society, Natural History Supplement 7: 5-6.

Bleeker, P. 1853. Nieuwe tientallen diagnostische beschrijvingen van niewuse of
weinig bekende vischsoorten van Sumatra Natuurkundig Tijdschrift voor
Nederlandsch Indie 5: 495-534.

1855. Nalezigen op de vischfauna van Sumatra. Visschen van Lahat en Sibogha.

Natuurkundig Tijdschrift voor Nederlandsch Indie 9: 257-280.

1863. Systema Cyprinoideorum revisum. Nederlandsch Tijdschrifr voor de

Dierkunde 5: 187-218.

1863. Atlas Ichthyologique des Indes Orientales Neerlandaises. Tome III. 150 pp.
+ Tab. CII-CXLIV. de De Breuk & Smits, Amsterdam.

Hora, S.L. 1942. Notes on Fishes in the Indian Museum. XLII. On the Sytematic
Position of the Indian Species of Scaphiodon Heckel. XLII. On the Systematic
Position of Cyprinus nukta Sykes. Records of the Indian Museum (Calcutta) 44: |—
14.

Eschmeyer, W.N. & Bailey R.M. 1990. Part I. Genera of Recent Fishes. pp. 7-433. Jn:
Eschmeyer, W.N. (ed.) Catalog of the genera of recent fishes. California Academy of
Sciences, San Francisco.

Hubbs, C.L. & Lagler, K.F. 1949. Fishes of the Great Lakes Region. Bulletin.
Cranbrook Institute of Science Bulletin 26: xi + 186 pp.

Inger, R.F. & Chin, P.K. 1962. The Fresh-Water Fishes of North Borneo. Fieldiana:

109

Zoology 45: 1-268.

Jayaram, D.C. 1981. The Freshware Fishes of India, Pakistan, Bangladesh, Burma,
and Sri Lanka — a handbook. xxii + 475 pp., 13 pls. Zoological Survey of India,
Calcutta.

Kottelat, M., Whitten, A.J., Kartikasari, S.N. & Wirjoatmodjo, S. 1993. Freshwater
Fishes of Western Indonesia and Sulawesi. Xxxviii + 221 pp., 84 pls. Periplus,
Singapore.

Rainboth, W.J. 1996. FAO species identification field guide for fishery purposes.
Fishes of the Cambodian Mekong. 265 pp., 27 pls. FAO, Rome.

Reid, G. McG. 1982. The form, function and phylogenetic significance of the vomero-
palatine organ in cyprinid fishes, Journal of Natural History 16: 497-510.

1985. A Revision of African Species of Labeo. 322 pp. J. Cramer, Hirschberg.

Roberts, T.R. 1989. The Freshwater fishes of Western Borneo (Kalimantan Barat,
Indonesia), Memoirs of the Calfornia Academy of Sciences 14: xii + 210 pp.

Siebert, D.J & Guiry, S. 1996. Rasbora johannae (Teleostei: Cyprinidae), a new
species of the R. trifasciata-complex from Kalimantan, Indonesia. Cybium 20: 395—
404.

Smith, H.M. 1945. The Fresh-Water Fishes of Siam, or Thailand. United States
National Museum Bulletin 188: xi + 622 pp.

Talwar, P.K. & Jhingran, A.G. 1991. Inland Fishes of India and Adjacent Countries.
Vol. I. xix + 541 pp. Oxford & IBH Publishing Co., New Delhi.

Weber, M. & de Beaufort, L.F. 1916. The fishes of the Indo—Australian Archipelago.
III. Ostariophysi: II Cyprinoidea, Apodes, Synbranchi. xv + 455 pp. E.J. Brill Ltd.,
Leiden.

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Ciliophora) from Europe and Japan. H. Berger & W. Foissner.
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Ten new taxa of chiropteran myobiids of the genus
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Indian Ocean echinoderms collected during the Sindbad
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CONTENTS

1 Arevision of the cladoceran genus Simocephalus (Crustacea, Daphniidae)

Marina J. Orlova-Bienkowskaja

63 Structural niche, limb morphology and locomotion in lacertid lizards (Squamata,
Lacertidae); a preliminary survey
E.N. Arnold

91 Hetereleotris georgegilli, a new species of gobiid fish, with notes on other Mauritian
Hetereleotris species
Anthony C. Gill

97 Revision of Schismatorhynchos Bleeker, 1855 (Teleostei, Cyprinidae), with the description of
two new species from Borneo
Darrell J. Siebert and Agus H. Tjakrawidjaja

Bulletin of The Natural History Museum

ZOOLOGY SERIES
Vol. 64, No. 1, June 1998