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Full text of "Bulletin of the Natural History Museum Zoology"

ISSN 0968-0470 



Bulletin of 

The Natural History 

Museum 



THE NATURAL 
HISTORY MUSEUM 



PRESENTED 
GENERAL LIBRAP 



Zoology Series 




VOLUME 64 NUMBER 1 25 JUNE 1998 



The Bulletin of The Natural History Museum (formerly: Bulletin of the British Museum 
(Natural History) ), instituted in 1949, is issued in four scientific series, Botany, 
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Assistant Editor: Dr B.T Clarke 



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World List abbreviation: Bull. nat. Hist. Mus. Lond. (Zool.) 
© The Natural History Museum, 1998 



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

The Natural History Museum 

Cromwell Road 

London SW7 5BD Issued 25 June 1998 

Typeset by Ann Buchan (Typesetters). Middlesex 

Printed in Great Britain by Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset 



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



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



THE NATURAL 
HISTORY MUSEUM 

29 JUN 1998 

PRESENTED 
GENERAL L I BRARY 



MARINA J. ORLOVA-BIENKOWSKAJA / , 

A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninsky prosp. 33, Moscow 
11707 1 Russia 



CONTENTS 



Introduction 2 

Material and methods 3 

Morphology 3 

Variability 5 

Systematic Accounts 6 

Subgenus Simocephalus s. str 6 

S. vetulus (O.F. Mullen 1776) 7 

S. mixtus Sars. 1903 1 1 

S. vetuloides Sars, 1898 12 

S. punt ■tutus sp. nov 14 

S. gibbosus Sars, 1896 15 

S. elizabethae (King, 1853) 16 

Subgenus 5. (Echinocaudus) subgen. nov 20 

S. obtusatus (Thomson, 1878) 21 

S. daphnoides Herrick, 1883 21 

S. (exspinosus) species group 22 

S. exspinosus (De Geer, 1778) 22 

S. congener (Koch, 1841) 25 

S. (acutirostratusj species group 26 

S. acutirostratus (King, 1853) 26 

S. victoriensis Dumont, 1983 30 

S. brehmi Gauthier, 1939 31 

S. rostratus Herrick, 1884 31 

Subgenus S. (Coronocephalus) Orlova-Bienkowskaja, 1995 39 

S. serrulatus (Koch, 1841) 41 

S. semiserratus Sars, 1901 46 

S . mirabilis sp. nov 49 

Subgenus S. (Aquipiculus) Orlova-Bienkowskaja, 1995 52 

S. latirostris Stingelin, 1906 53 

5. heilongjiangensis Shi, Shi. 1994 53 

S. lusaticus Herr, 1917 53 

Nomina dubia and species transferred to the genus Daphnia 54 

Key to the subgenera and species of Simocephalus 54 

Check list of Simocephalus 60 

Acknowledgements 60 

References 60 



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. nov.; subgenus 5. (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 



M.J. ORLOVA-BIENKOWSKAJA 



INTRODUCTION 



Freshwater Daphniidae of the genus Simocephalus Schodler, 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 



to be cosmopolitan, pantropical etc. 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)andS. (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, a 1 - 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 ot '.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, o -ocellus, p - postabdomen, pap -proximal abdominal process, pc - 
postabdominal claw, pe - parthenogenetic eggs, ps - plumose setae of inner surface of ventral valve margin, pvm - 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, 1 st - 1 st trunk limb, 2nd - 2nd trunk limb, 3rd - 3rd trunk limb, 4th - 4th trunk limb, 5th - 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. lusaticus, 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, 9 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. 



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:pvm) oblique, almost straight. Point of 
divergence of valves (Fig. l:dv) dorsal to dorso-posterior angle 
(Fig. l:dpva). Dorsal, posterior and ventral margins with denticles 
or smooth. Denticles arranged in 2 rows on dorsal margin (Fig. 

1 :dd). Inner valve surface with a row of plumose setae on ventral 
margin (Fig. l:ps), a row of setules groups on posterior margin (Fig. 
Is) and 2-5 plumose denticles near ventro-posterior angle (Fig. 
l:d). Parthenogenetic female with 1-30 eggs in brood pouch. 
Ephippium containing 1 egg (Fig. 3C). 

Reticulation 

Valves and head reticulated. Reticulation consists of oblique stripes 
somewhat intersecting in most of 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. l: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. l:vhm) with depression, deep or 
shallow, near rostrum. Fornices very broad (Figs 4; 5; l: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 1 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 l:p; 12A.B) 

High, with anal bay (Fig. fab), supra-anal angle (Fig. fsa) and 2 
rows of anal teeth (Fig. fat). Distal anal teeth large, covered with 
setules. Proximal teeth small, smooth. Dorsal part with groups of 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 3 S. vetulus. A, male, B, parthenogenetic female attached to a surface, C, ephippial female. 



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

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

Male 

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



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 8 A 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 5. vetulus head and mouih 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. 1 6C). A similar result was obtained for 
5. 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). 



M.J. ORLOVA-BIENKOWSKAJA 



SYSTEMATIC ACCOUNTS 



Subgenus Simocephalus s. str. 

TYPE SPECIES. Simocephalus vetulus (O.F. Miiller, 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 neither ridges 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). 



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 1st 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 




Fig. 5 S. vetulus. Head shield. HP - head pores. 



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 1-13 (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 of the types shows that one of these species isS. vetulus 
(1-13); the other is 5. mixtus (14-16). 

Similar reasoning shows that 2 species of Simocephalus s. str.: 5. 
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. Mullen 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: Schodler, 1858: 18; S. 
vetulus vai.angustifronsLiWjebovg, 1900: 171;5. vetulusvai. brandti 
Cosmovici, 1900: 156 syn. nov. (nee Daphnia brandtii Fischer, 
1848); 5. 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°34Ti, 11.5. 
1901: MPA:9ad. (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: 
5. vetulus angustifrons Lilljeborg, 1900: Lectotype (designated 
here): Sweden, Uppsala, 9. 10. 1882, leg. Lilljeborg: MPA: 9 ad. 
(ZMU, 399). Paralectotypes collected with lectotype: MPA: 
13 9 9 ad., 33 9 9juv., 7 9 9e., 5cfcf(ZMU, 399). Other speci- 
mens: More than 2000 specimens ( 9 9 ad., 9 9 juv., 9 9 e.,cf <f) 
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. 9 9 ad.: 1.3-2. 9mm.. 9 9e.: 1,2- 
l,9mm,c?C?: 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 5. vetulus. A. 1st limb of female, B. hook of endopod of 1st limb of adult male. C, 1st limb of male. D, hook of endopod of 1st 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' (Mtiller, 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 




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



differs from S. vetulus (Monoculus sima) in rostrum shape. How- 
ever, judging from the illustrations in the original description, these 
species are identical. Information about the types of S. nasutus is 
lacking. I agree with Lilljeborg (1900), that S. nasutus is a junior 
synonym of 5. vetulus. 

S. vetulus var. brandti Cosmovici was described from Romania. 
There is no information about the type material. Cosmovici (1900) 
writes that he named this variety thus because it is intermediate 
between S. vetulus and S. brandtii Fischer (= S. serrulatus). Refer- 
ring to the illustrations by Cosmovici, it is the junior synonym of S. 
vetulus. 



S. vetulus var. angustifrons Lilljeborg differs from the typical 
form in the presence of a prominence on the ventral head margin. 
Some authors (Behning, 1941; Manujlova, 1964) consider this 
variety to be a subspecies, but I believe it to be a synonym, because 
I have found specimens both with and without the prominence in the 
type material of S. vetulus var. angustifrons (Fig. 22). Moreover the 
animals with such a prominence sometimes occur in the most of 
Simocephalus species. 

S. vetulus gebhardti and S. mixtus hungaricus were described 
from Hungary. The author (Ponyi. 1955, 1956) writes that these 
subspecies differ from S. vetulus vetulus in head shape and denticles 



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



11 





Fig. 10 5. 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: Flossner, 1986: 179, partim. S. beianensis Shi, Shi, 1994: 
405 syn. nov. 



Type material. Lectotype (designated here): Mongolia, Eastern 
slope of Khingan mountain, 8. 11. 1911: MPA:9ad. (BMNH, 
1995.742). Paralectotypes collected with lectotype: MPA: 149 9ad., 
16 9 9juv. (BMNH, 1995.743-752). 

Material examined. Lectotype, paralectotypes and other speci- 
mens: more than 2500 specimens (9 9 ad., 9 9juv.,9 9e.,cfd") 
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. 
1.9mm,cfcf 



Measurements. 9 9 ad.: 
1.0-1, 3mm. 



1.0-2. 9mm, 9 9e.: 1,2- 



12 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 11 S. 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 Flossner (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, 1 9 1 0) is very brief. Judging from illustrations, S. corniger 
is a junior synonym of 5. 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 5. 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; 5. 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: 9 ad. (ZICC, 4690). 
Paralectotypes collected with lectotype: 38 9 9 ad. (ZICC, 4690). 
The vicinity of Jana river: CBS: 9 ad. (ZICW). Dolgulach, 16-18. 6. 
1885:3 9 9 ad. (ZICW). 

MATERIAL EXAMINED (Fig. 2 1 ). Lectotype, paralectotypes and other 
specimens from AC: Russia, vicinity of Yakutsk, 7. 1990, leg. 
Smirnov: 18 9 9 ad., 9 9 9juv. Chita, sand-pit, 9. 9. 1991, leg. 
Smirnov: more than 70 9 9 ad., 70 9 9juv„ lOOcfcf, 40 9 9 e. 



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



13 



«;.-*» •■■■ K- > ■?"*!*■ .' ■ -a 
^ :: ^i&-'- .■■■■: -si 




Fig. 12 5. 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. 



14 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 13 5. 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: 
4 9 9 ad., 2 9 9 e. Magadan region, Verkhnee lake, 18.8. 1981, leg. 
Streletskaja: 13 9 9 ad., 8 9 9juv. 

Diagnosis. Measurements. 9 9 ad.: 1.3-2.4 mm., 9 9 e.: 1,2- 
1,9 mm, cfcf: 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 
1 19°45'W, leg. Berner: MPA: 9 ad. (BMNH) 1997. 1698. Paratypes 
collected with holotype: MPA: more than 50 9 9 ad., 20 9 9 juv., 
209 9e., 20cfcf(BMNH 1997. 1699-1708 and AC). 

Diagnosis. Measurements. 9 9 ad.: 1. 5-2. 23mm., 9 9 e.: 1,2- 
l,9mm,cfcf: l,l-l,3mm. 

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



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



15 




Fig. 14 S. 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 5. 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, 1 896 

Fig. 26 

Simocephalus gibbosus Sars, 1896: \5;S. vetulus gibbosus: Dumont, 
1983: 102. 

Type material. Lectotype (designated here): Australia, Sydney, 
Centennial park: CBS: 9 ad. (ZMO.F9766, Mp. 170). Paralectotypes 
collected with lectotype: 5 9 9 ad. (ZMO, F 9766, Mp. 170), MPA: 
15 9 9 ad. (ZMO, F 19261). 

Material examined (Fig. 21). Lectotype, paralectotypes and 
other specimens: more than 250 specimens ( 9 9 ad. and 9 9juv.) 



16 



M.J. ORLOVA-BIENKOWSKAJA 




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



from 1 1 localities in Australia: New South Wales, Victoria, Queens- 
land, Northern Territory. The material is in AM and AC. 

DIAGNOSIS. Measurements. 9 9 ad.: 1.0-2.4mm., 9 9e.: 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( 1 983) 
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 

Daplmia Elizabethae King, 1853a: 247; Simocephalus vetulus: 
Schodler, 1877: 18 partim, Negrea, 1983: 138 partim; S. vetulus 
elizabethae: Dumont, 1983: 98; 5. 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. 17 S. vetulus, variation of abdomen and postabdomen, female. A, postabdomen, B, abdominal processes. 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 18 5. 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 ( 9 9 ad., 9 9juv., 
9 9e., d"cf) 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 9 ad.: 1.2-3.4mm., 9 9e.: 1.2-1.9, 
Cfcf: 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 



19 



1 2 3 4 5 6 7 8 9 10 U 12 13 14 15 16 




B 



14-16 



1-13 





Fig. 19 Statistical analysis of 16 series of Simocephalus s. str. from Europe. 1-13 - S. vetulus, 14—16 - 5. mixtus. A, result of cluster analysis, B, C, 
diagrams of characters. 



20 



M.J. ORLOVA-BIENKOWSKAJA 



1 23456789 10 






Fig. 20 Statistical analysis often series of Simocephalus s. str. from East Siberia and Far East. 1—7-5. vetuloides, 8-10-5. 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). Schodler (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 5. 
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 corner 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 1st 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).Vasdeferensopeningnear 
its base. Postabdomen with 5-6 anal teeth on each side. Dorso- 
posterior valve angle with rounded or pointed prominence. 



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



21 



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. 

5. obtusatus (Thomson, 1878) 

Fig. 31 

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

Type material. No information. Type locality: New Zealand, 
Dunedin. 

Material examined. New Zealand, Lake Takapuna, leg. 
Henry: 9 ad. (AM, 7182). 

Diagnosis. Measurements. 9 9 ad.: 2.0-2. 5mm, cfcf: 1.0-1. 2mm. 
Both sexes. Frons rounded (Fig. 3 ID). 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. 3 IE). Basal pecten of 
postabdominal claw with 10-12 large well-spaced spines (Fig. 
31C). Size of spines maximal in middle. 

Distribution. (Fig. 32) New Zealand. 

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



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, 1 883 

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: 3 9 9 ad., 3 9 9juv. (AC). Peru, vicinity of Pucalpa, 
pond near Ucayali river, 2. 1987, leg. Pegasov: 4 9 9 ad. (AC). 

Diagnosis. Measurements. 9 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. 




# S . vetulus 
S . gibbosus 
® S . punctatus 



OS. mixtus (Js. vetulus & s. mixtus 

®S. elizabethae ©S. elizabethae & S. gibbosus 

©S. vetuloides &S. mixtus Q) S . vetuloides 



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



22 



M.J. ORLOVA-BIENKOWSKAJA 




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. 5. 
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 



23 



Monoculus exspinosus De Geer, 1778: 457; Daphnia exspinosa: 
Koch, 1841: 35; Daphnia sima: Lievin, 1848; Baird, 1850: 95; 
Simocephalus exspinosus Schodler, 1858: 20; Lilljeborg, 1900: 177; 
Daphnia australiensis Dana, 1852: 1271; Sars, 1888: 15; S. 
exspinosus australiensis: Dumont, 1983: 104: 5. sibiricus Sars, 
1898: 329 syn. nov. ; S. productus Sars, 1903: 173; 5. 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: 9 9 9 ad. (ZICC, 4691). S. productus Sars, 
1903: Lectotype (designated here): Kazakhstan, Akmolinsk region: 
MPA: 9 ad. (ZICC, 7098). Paralectotypes collected with lectotype: 
35 9 9 ad. (ZICC, N7098). Other specimens: more than 1000 speci- 
mens (9 9 ad., 9 9juv.,9 9e,d"d') from 56 localities in Russia, 
Ukraine, Georgia, Kazakhstan, Uzbekistan, Tadjikistan, Mongolia, 



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 9 e.: 1.2 
1.9mm.cfcf: 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 Schodler are often 
erroneously thought to be the authors of the species, because Koch 
( 1841 ) described and drew it and Schodler ( 1858) was the first to 




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



24 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 24 S. 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. 

5. australiensis was originally described insufficiently (Dana, 
1 852). Dana's collection with the type was lost on a ship which sank 
(D. Frey, personal communication through N.N. Smirnov). 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 (Flossner, 1972; 
Negrea, 1983; Margaritora, 1985; Michael & Sharma, 1988). Iagree 
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 5. 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 aUSimocephalus 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. pimctatus 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: 
Schodler, 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 
20 9 9 ad., 20 9 9juv., 10 9 9 e. Vicinity of the Lake Baikal, Maloe 
More, pool at the swamp, 19. 8. 1982, leg. Glagolev: 10 9 9 ad., 
14 9 9 juv. Vicinity of the Lake Baikal, Proval, water-meadow at 
Oblom, 20. 8. 1982, leg. Glagolev: 2 9 9 ad. All series are in AC. 

Diagnosis. Measurements. 9 9 ad.: 1.5-2. 2mm, 9 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 



M.J. ORLOVA-BIENKOWSKAJA 



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 a synonym of S. 
exspinosus (Sars, 1888; Flossner, 1972; Margaritora, 1985; Sharma 
& Michael, 1988) or a variety (subspecies) (Behning, 1941). But 
Sramek-Husek et 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 Schodler, 
1877; S. vidyae Rane, 1983: 154; S. vidyae gajareae Rane, 1986: 
168. 



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

Material examined. (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 9 9 ad., 20 9 9 juv. New South Wales, Casino, 28°52'S 
1 53°3'E, leg. Henry: 9 ad. New Caledonia, dam near La Foa, 2 1 °50'S 
166°53'E, 8. 8. 1981, leg. De Deckker: 9juv. Queensland, pool at 
the road side, 30. 6. 1974: 2 9 9 ad., 5 9 9 juv. 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 frcm 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 5. 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 



27 




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



28 



M.J. ORLOVA-BIENKOWSKAJA 




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



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



29 




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



Fig. 30 S. exspinosus female, trunk limbs. A, 1st limb, B, endite of 2nd limb. 



30 



M.J. ORLOVA-BIENKOWSKAJA 



Schodler (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:9ad. (AM, P31316). 

Material examined. (Fig. 32) Holotype and other specimens: 



Australia, New South Wales, a lake near Cooma, 12. 5. 1975: 
4 9 9 ad., 12 9 9juv. Lake Maffa, 13.5. 1975:3 9 9 ad., 10 9 9juv. 
South Australia, Tatiara, 4km N of Bordertown, 6. 11. 1979, leg. 
Zeidler: 5 9 9 ad., 9juv. A lake on Nimakel-Bumbala road, 14. 5. 
1975: 8 9 9 ad., 2 9 9 juv. 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. (Fig. 32) Australia: New South Wales, South Aus- 
tralia, Victoria. 

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, 
E, postabdomen, F, male. 



894). A, parthenogenetic female, lateral view, B, parthenogenetic female, dorsal view, C, postabdominal claw, D, head, 



REVISION OF S1MOCEPHALUS DAPHNIIDAE 



31 




O S. exspinosus (J s. victoriensis & S. exspinosus O S. brehmi 

• s. acutirostracus f) S . acutirostratus &S. exspinosus © S. obtusatus 

©S. viccoriensis © S. exspinosus & S. congener © S. daphnoides 

© S. rostratus (D undescribed species of S. (acutirostratus) group 



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



5. brehmi Gauthier, 1939 stat. nov. 

Fig. 37 

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



144; Simocephalus 



TYPE MATERIAL. Types (5 9 9 ad.) 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 5. 
acutifrons Johnson. Holotype: South Africa, Kempton Park. Johan- 
nesburg: MPA:9ad. (BMNH). Paratype collected with holotype: 
MPA: 9 ad. (BMNH). Other specimens: Tanzania, Mt Hanang: 
23 9 9 ad., 2 9 9juv. (MCA). Southern Rhodesia, Plumtree, 7. 2. 
1954: 4 9 9 ad., 9 e., 2 9 9 juv. (ZICC). 

Diagnosis . Measurements. 9 9 ad . : 1 . 0-3 . Om m . 
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- 



sia, Tanzania, South Africa. This species is also reported from Brasil 
by Brehm (Gauthier. 1939). Unfortunately, no specimen of this 
species group from South America 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 andS. 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: 10 9 9 ad., 10 9 9 juv. (AC). 



32 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 33 S. 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 



33 




Fig. 34 S. 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 



35 




Fig. 36 5. 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 



37 




Fig. 38 S. rostratus, parthenogenetic female. 



38 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 39 S. 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 



39 




Fig. 40 S. 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. brehtni 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-^2). 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 




Fig. 41 S. 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 5. 
semiserratus. The male of 5. 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 



41 



5. 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;S. serrulatus var. productions 
Stingelin, 1904: 57; S. serrulatus var. montenegrinus Werestchagin, 
1912: 7; 5. serrulatus var. mixta Grochmalicki, 1915: 220 (nee 5. 
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; 5. 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 ( 1 995a)): Montenegro, Lake Scutari, 
15. 6. 1911, leg. Werestchagin : MPA: 9 ad. (ZICC, 7085). 
Paralectotypes collected with lectotype: MPA: 3 9 9ad.,9juv 
(ZICC, 7085, 7086), Montenegro, vicinity of Rijeka, leg. 
Werestchagin: CBS: 2 9 9 ad., 2 9 9 juv. (ZICW). S. capensis Sars, 
1895: Lectotype (designated by Orlova-Bienkowskaja (1995a)): 



SouthAfrica, Knysna, hatched from dry epphipia: MPA: 9 ad. (ZMO, 
F 18357). Paralectotypes collected with lectotype: MPA: 15 9 9 ad., 
10 9 9juv., 8 9 9e. (ZMO, F 18357), 16d"cf(ZMO, F 183578). 
Other specimens: about 1500 specimens ( 9 9 ad., 9 9juv., 9 9e. 
andcf cf) 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, 9 9 e. 1.0- 
1.5mm,cfd'': 0.7-1. 0mm. 

Female. Dorso-posterior valve prominence large, separated from the 
rest of valves by deep embay ment. 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 1st 
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 




Fig. 42 S. serrulatus, female. A, antennule, lateral, B, antennule. dorsal, C, 1st trunk limb, D, endite of 2nd trunk limb. 



42 



M.J. ORLOVA-BIENKOWSKAJA 




#S. serrulatus O S. semiserratus 

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



S. mirabilis 



because of these variations. However, I believe, that 5. 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 is 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. intermedins, 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 5. 
vetulus. The name S. intermedins Studer is not the secondary 
homonym of S. intermedins (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. 41 A). It is 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 5. 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 andS. serrulatus. Sharma & Sharma (1990) have studied the 
types and sunkS. surekhae into the synonymy of 5. 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; Flossner, 1972). In the opin- 
ion of Brehm (1933) this variety described from Gao (Mali) 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 



43 




Fig. 44 S. 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. 



44 



M.J. ORLOVA-BIENKOWSKAJA 




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






REVISION OF S1MOCEPHALUS DAPHNIIDAE 



45 




Fig. 46 S. mirabilis sp. nov.. female. A. endite of 2nd trunk limb, B, postabdominal claw, C, 1 st 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 (Flossner, 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 a synonym of S. capensis. because he found some specimens with 
intermediate characters in Paraguay. Michael & Sharma (1988) 
believe it to be a synonym of S. serrulatus. I agree with them because 
the original description, provided with a good illustration, contains 
all the important characters of the latter species. 

S. kerhervei and S. 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 andS. 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 fromS 1 . serrulatus, S. inflatus 
and S. americanus by the elongate, pointed head and the large 



46 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 47 S. latirostris, parthenogenetic female. A, lateral view. B. anterior view. C. rostrum and antennule. 




Fig. 48 5. latirostris. A, male, B, rostrum and antennule, male, C, 
ephippial female. 



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 5. 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 



47 




Fig. 49 S.latirostris appendages, female. A, 5th trunk limb, B, 4th trunk limb, C. 1st trunk limb, D, 3rd trunk limb, E, 2nd trunk limb. F, maxillule. 



48 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 50 S. latirostris. A, lateral view of 1st trunk limb, male, B, frontal view of 1st 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 



49 



Paralectotypes collected with lectotype: CBS: 9 9 9 ad., 2 9 9juv. 
(ZMO, F 9176, F 9177), Argentina: MPA: 15 9 9 ad.. 10 9 9juv„ 
69 9e.,d"(ZMO, F 18438); MPA: 27 9 9 ad., 29 9juv„ 39 9e. 
(BMNH, 1901. 12. 12.251-261). 

Material examined (Fig. 43). Lectotype, paralectotypes. 

Diagnosis. Measurements. 9 9 ad.: 1. 0-2. 0mm. 9 9 e. 1.0- 
1 . 5mm, cTcf: 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 Vi 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. 

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

Remarks. Daday (1905) believes 5. semiserratas and S. capensis 
to be one species. Kanduru (1981) and Michael & Sharma (1988) 
sink S. semiserratus into the synonymy of 5. serrulatus. Sars ( 1 90 1 ) 
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. 



are in this species always limited to their uppermost part only'. It is 
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 5". 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 
ofLangan Park lake, 24. 5. 1987, leg. Fitzpatrik: MPA: 9 ad. (BMNH 
1997. 1709). Paratypes: collected with holotype: MPA: 11 9 9 ad., 
9 9 9juv. (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: 10 9 9 ad.. 2 9 9juv. (AC); Argentina, Rio Parana, 
Catay pond, leg. Frutos: MPA: 4 9 9 ad., 7 9 9juv. (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 Vi of posterior and less than 1/3 of dorsal 




# S. latirostris O S. heilongjiangensis O S. lusaticus 

6s. lusaticus & S. heilongjiangensis 
Fig. 51 Locations where the species of 5. (Aquipiculus) were collected for this study or reported in literature. 



50 



M.J. ORLOVA-BIENKOWSKAJA 




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, 1st 
trunk limb, G, 4th trunk limb, H, ephippial female (head omitted), I head pores. 



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



51 




Fig. 53 S. 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). 



52 



M.J. ORLOVA-BIENKOWSKAJA 




Fig. 54 5. lusaticus. 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 1 st prominence respectively. 



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

Remarks. S. mirabilis differs fromS. serrulatus andS. 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 5. (Aquipiculus) Orlova-Bienkowskaja, 
1995 

Type species. Simocephalus latimstris 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 
on inner 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 1st 
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 



53 



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; BrandorffeM/., 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, 111/24). Paralectotype: 9juv., 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 9 9 ad., more than 50 9 9juv.. 
31 9 9e.. 8o"cT(BMNH and AC). Brasil, Rio Negro, Anavilanas 
Margen, 14.9. 1979: 9 ad. 

Diagnosis. Measurements. 9 9 ad.: 1.0-1.8mm,c?cf : 0.6-0.9mm. 
Both sexes (Figs 47-50). Rostrum very long, rostrum length 6.4- 
9. 1 % of body length in 9 9 ad., 5.4-7.7% incf cf. 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, 5th tooth more 
than half length of 4th. 
Male. Vas deferens opening at base of supra-anal angle. 

Distribution. (Fig. 5 1 ) The tropics and subtropics of South and 
Central America. Numerous records of S. latirostris 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. 5. 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: 1 15; Dumont & Van DeVelde, 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. 



Type MATERIAL. Holotype. Moershan Town (45°I5'N, I27°30E), 
Shangzhi County, Heilongjang Prvince, 6.8.1990., leg. Shi 
Xinlu. 9ad. Allotypecfand paratypes 309 9and I0cf cf 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: 
1 10 specimens ( 9 9 ad., 9 9juv. and 9 9e.) 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 (9 9 ad. and 9 9juv.) 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. latirostris: 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 9 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 frcm Africa differ from others in shorter 
rostrum. However I believe that the African 5. 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^fl/., 1962: 259; Flossner, 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.: LS^mm^d" about 1mm. 



54 



M.J. ORLOVA-BIENKOWSKAJA 



Both sexes (Fig. 54). Rostrum shorter than in S. latirostris; its lateral 
margins below central part. Antennule shorter than in S. latirostris, 
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-Huseke/<3/., 1962;F16ssner, 1972;Kamifiski, 
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 ( 1 894) and Sramek-Husek 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 5. 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 5. 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 dieTendenz 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 (Flossner, 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 



(Studer, 1878; Brady, 1918). This is S. gelidus Brady, 1918 = 
Daphnia gelida comb. nov. and S. intermedins 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 &d" :Postabdominal claw without spines. Inner and outer side 
of claw with fine setules (A). Frons rounded, without denticle (B) 

2 

- Fig. 55 . 9 & d" : 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 denticles^. (Echinocaudus) subgen. 
nov. 10 

- Fig. 55. 9 &cf: 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- 
kowskaja, 1995 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). cf: Vas deferens opening on top of supra-anal angle (L). 
Simocephalus s. str 3 

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

3. Fig. 56. 9 : Ocellus point-like (B). Dorso-posterior valve angle rounded, 
without prominence (A). Occurs in North America 

S. punctatus sp.nov. 

- Fig. 56. 9 : Ocellus elongate (C). Dorso-posterior valve angle of differ- 
ent shape 4 

4. Fig. 56. 9 : Dorso-posterior valve angle with very small prominence 
(D). The most common European species. Occurs also in North Africa 

S. vetulus (O.F. Muller. 1776) 

- Fig. 56. 9 : Dorso-posterior valve angle with larger prominence (E) 

5 

5. Fig. 56. 9 : Depression of ventral head margin near rostrum deep (F) 

6 

- Fig. 56. 9 : Depression of ventral head margin near rostrum shallow, 
sometimes absent (G). Species occur in Australia, Tasmania and New 
Guinea 7 

6. Fig. 56. 9 : Diameter of dorso-posterior valve prominence exceeds its 
length (H). Dorsal valve margin protruding backward (I) 

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 
Eastern Siberia S. vetuloides Sars, 1898 

7. Fig. 56. 9 : Dorsal valve margin protruding backward strongly (L) 

S. gibbosus Sars, 1896 

- Fig. 56. 9 : Dorsal valve margin not protruding backward (M) 

5. elizabethae (King, 1853) 

8. Fig. 57. 9 & cf: lateral prominences on valves present (A). Rare species. 

Occurs in East Europe and China S. lusaticus 

Herr, 1917 



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



55 




Simocephalus s. str 



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



56 



M.J. ORLOVA-BIENKOWSKAJA 




S. mixtus X - / S. vetuloides s - gibbosus s. elizabethae 



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



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



57 




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



- Fig. 57. 9 & cf : No lateral prominences on valves (B) 9 

9. Fig. 57. 9 : Rostrum very long, its lateral margin elevated above central 
part (C). Dorso-posterior valve prominence pointed (D). Occurs in 
South America S. latirostris Stingelin. 1906 

Fig. 57. 9 : 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 

S. heilongjiangensis Shi, Shi, 1994 

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



13. 



Fig. 58. 9 : Frons pointed (C). Two supra-anal angles (D) 
S. (acutirostratus) species group 14 

Fig. 58. 9 : Ventral head margin very convex (E). Spines of basal pecten 

of postabdominal claw well-spaced (F). Occurs in New-Zealand 

S. obtusatus (Thomson, 1878) 

Fig. 58. 9 : Ventral head margin almost straight (G). Spines of basal 
pecten of postabdominal claw close-set (H) 12 

Fig. 58. 9 : Dorso-posterior valve angle with large pointed prominence 
(I). Occurs in America S. daphnoides Herrick, 1883 

Fig. 58. 9: Dorso-posterior valve angle with rounded prominence or 
without prominence (J) 13 

Fig. 58.9: Basal pecten of postabdominal claw of 8-12 spines of 
moderate size (K) 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) 



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

- Fig. 58. 9 : Dorso-posterior valve angle with distinct prominence covered 
with denticles (N) 15 

15. Fig. 58.9: Dorso-posterior valve prominence separated above and 
below by deep, wide depressions. Diameter of circle inscribed in it 
moderate (O). Occurs in Africa 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 

large (P). Occurs in Australia and Asia 

5. acutirostratus (King, 1853) 

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 

16. Fig. 59. 9: Ocellus elongate. Frons without denticles (A). Occurs in 
America S. mirabilis sp. nov. 

- Fig. 59. 9 : Ocellus short. Frons with denticles (B) 17 

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 S. serrulatus (Koch, 1841) 

- Fig. 59. 9 : 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 Vi of posterior and less than 1/3 of dorsal 
margin. Occurs in South America S. semiserratus Sars, 1901 



58 



M.J. ORLOVA-BIENKOWSKAJA 




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



REVISION OF SIMOCEPHALUS DAPHNIIDAE 



59 



16 




S. semiserratus 



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



60 



M.J. ORLOVA-BIENKOWSKAJA 



CHECK LIST OF SIMOCEPHALUS 

Subgenus Simocephalus s. str. 

1. S. vetulus (O.F. Muller, 1776) {Daphne vetula) 
Daphnia sima O.F. Muller, 1785 
Monoculus nasutus Jurine, 1 820 

5. vetulus var. angustifrons Lilljeborg, 1900 
S. vetulus var. brandti Cosmovici, 1900 syn. nov. 
S. vetulus gebhardti Ponyi, 1955 
S. mixtus hungaricus Ponyi, 1956 

2. S. elizabethae (King, 1853) (Daphnia Elizabethae) 
S. dulvertonensis Smith, 1 909 

3. S. gibbosus Sars, 1896 

4. S. vetuloides Sars, 1898 

5. S. mixtus Sars, 1903 

S. corniger Methuen, 1910 syn. nov. 
S. beianensis Shi, Sbi, 1994 syn. nov. 

6. S. punctatus sp. nov. 

Subgenus S. (Echinocaudus) subgen. nov. 

7. S. obtusatus (Thomson, 1878) (Daphnia obtusata) 

8. S. daphnoides Herrick, 1883 

S. Iheringi Richard, 1897 syn. nov. 

S. fonsecai Bergamin, 1939 syn. nov. 

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

S. (exspinosus) species group 

9. S. exspinosus (De Geer, 1778) (Monoculus exspinosus) 
Daphnia australiensis Dana, 1852 

S. sibiricus Sars, 1898 syn. nov. 

S. productus Sars, 1903 

S. himalayensis Chiang & Chen, 1974 syn. nov. 

5. vamani Rane, 1985 

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

S. (acutirostratus) species group 

11. S. acutirostratus (King, 1853) (Daphnia Elizabethae var. 
acuti-rostrata) 

S. paradoxus Schodler, 1 877 

S. vidyae Rane, 1983 

S. vidyae gajareae Rane, 1986 

12. S. victoriensis Dumont, 1983 

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

S. acutifrons Johnson, 1954 syn. nov. 

14. S. rostratus Herrick, 1884 

Subgenus S. (Coronocephalus) Orlova-Bienkowskaja, 1995 

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

D. intermedia Lievin, 1848 

S. americanus Birge, 1878 

5. capensis Sars, 1895 

S. inflatus Vavra, 1900 

S. serrulatus var. productifrons Stingelin, 1904 

5. serrulatus var. montenegrinus Werestchagin, 1912 

S. serrulatus var. mixta Grochmalicki, 1915 

S. serrulatus var. rotundifrons Brehm, 1933 

S. kerhervei Bergamin, 1939 

S. agua-brankai Bergamin, 1939 

S. serrulatus var. armata Brehm, 1956 

S. serrulatus var. pelagicus Brehm, 1959 

S. surekhae Rane, 1985 



16. S. semiserratus Sars, 

17. 5. mirabilis sp. nov. 



1901 



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 

5. 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. I 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. Monakov, 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. 1 am also grateful to A.O. 
Bierikowski for the help in the work. 



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Bull. not. Hist. Mus. Lond. (Zool.) 64( 1 ): 63-89 Issued 25 June 1 998 

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 

Introduction 64 

Phylogenetic relationships of the Lacertidae 65 

Structural niches of lacertid lizards 65 

Overview of lacertid structural niche space 65 

Structural habitats occupied by groups within the Lacertidae 65 

Primitive Palaearctic forms 65 

Members of the Armatured clade 67 

Evolutionary change in structural niche 69 

Morphology 69 

Body proportions and vertebral number 69 

Relative tail length 70 

Limb proportions and structural niche 71 

Sexual dimorphism in limb length 72 

Relative proportions of femur and tibia 73 

Patterns of limb growth 73 

Evolutionary plasticity of limb proportions 73 

Functional aspects of differences in limb proportions 73 

Differences in the caudifemoralis longus muscle 74 

General anatomy of the hind leg 74 

Structure of the pes 74 

The pes in ground dwelling lacertids from open situalions 75 

The pes in lacertids regularly climbing steep, open surfaces 75 

Variations in the direction of kinking in toe 5 of lacertids 77 

Patterns of digital kinking in climbers of other families 77 

Structure of the manus 78 

The manus in ground dwelling lacertids from open situations 78 

The manus in lacertids regularly climbing on steep open surfaces 78 

Characteristics of the feet in other lacertids 78 

Special structures of the digits 80 

Expanded subdigital lamellae 80 

Keeling on subdigital scales 80 

Digital fringes 80 

Locomotion and function 81 

Locomotion in ground dwellers of the Armatured clade 81 

Movements of the hind limb 83 

Rotation of the femur and supposed restrictions on its movement 83 

The supposed problem of crural rotation 83 

A partial model of hind limb movement 83 

Other hind limb gaits in ground dwelling lizards - continuous gearing 84 

Movements of the foreleg in ground dwellers 84 

Functional aspects of the limbs and feet of ground dwelling lacertids 84 

Ground locomotion in climbing species 84 

Locomotion in climbers on steep open surfaces 84 

Movements of the hind limb 85 

Movements of the fore limb 86 

Other patterns of locomotion in specialised climbing lacertids 86 

Problems of upward vertical locomotion 86 

Functional aspects of the limbs and feet of specialised climbing lacertids 86 

Climbing in specialised ground dwelling species 86 

Concluding remarks 88 

Acknowledgements 88 

References 88 

) 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 \^\ 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 theArmaturedclade 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 



65 



PHYLOGENETIC RELATIONSHIPS OF THE 
LACERTIDAE 

The successively distant outgroups of the Lacertidae appear to be the 

1 . theTeiioidea, 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 
paraphyleticL«cw/a from which is derivedAlgyroides andPodarcis. 
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, 1 920; Arnold. 
1973, 1989a) and, although immunological data do not suggest 
such a relationship, DNA sequence does give some admittedly 
weak support. 

3. Lacerta vivipara. 

4. Podarcis and its relatives Lacerta andreanszky'i and the sister 
species, L. chtgesii and L. perspicillata. 

5. 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 andL. aurelioi, L. hor\'athi, L. monticola, L. mosorensis. 

1 . Algyroides 

8. Southern 'archaeolacertas': L. bedriagae, L. cappadocica, L. 
danfordi group (Lacerta anatolica, L. danfordi, L. oertzeni), 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. 



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. 1 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 



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 Takydromus 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 off! hispanica andf! 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 is 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 LIZARDS 



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. hoiTathi, 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 isL. oxvcephala. (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 0. cyanura and 0. 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, 



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 



E.N. ARNOLD 



dense tussocks of coarse and spiny vegetation. (Sources summarised 
by Arnold, 198%). 

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, T. 
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, T. 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, Takydromus 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). 

Iclmotropis (Tropical southern Africa) 

Ground dwelling in arid and mesic savannah often with sandy soil 

(Branch, 1988; FitzSimons, 1943). 



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 andM. suborbitalis), vegetated 
hummocks separated by open areas of soft sand (M. reticulatus), 
areas of looser sand and more open vegetation (the subgenusSawn'res, 
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 is 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 is 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 andM. 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 



69 



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 
Takyd ramus. 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 Takydromus 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 Takydromus 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 Takydromus. 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 



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 ofTropidosaura 
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 theArmatured 
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 



E.N. ARNOLD 



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 thePsammodromus 
hispanicus group, Lacerta agilis, L. derjugini, L. praticolal 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 



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 



0.8 



0.7 



0.6 



0.5 *- 




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; • - 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 intermedins, P. Latastia longicaudata, Q. Ophisops schlueteri, 
R. Pedioplanis lineoocellata, S. Acanthodactylus schmidti, T Acanthodactylus scutellatus, U. Helioholus 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, 1. Poromerafordi, m. Podarcis hispanica, n. Podarcis muralis, p. Lacerta viridis, q. Podarcis melisellensis, r. Podarcis sicula, s. Lacerta 
laevis, t. Podarcis peloponnesiaca, u. Lacerta trilineata, v. Psammodromus algirus. 



NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS 



71 



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 inL. 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 1 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 

i Lacerta oxycephala. Forms which climb considerably but also run in 

! more or less horizontal situations have even longer and less equal 

1 limb pairs. Species that scarcely climb and occupy open ground 

habitats all have very long hind legs and short front ones. This is best 



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) 
Takydromus septentrionalis (1 lm.lOf) 
Gallotia atlantica (3m, 3f) 
Gallotia g. caesaris (3m, 3f) 
Psammodromus algirus (6m, 6f) 
Psammodromus hispanicus (7m, 100 
Lacerta vivipara (10m, 100 
Lacerta agilis bosnica (lOm.lOf) 
Lacerta viridis ( 1 Om, 1 Of) 
Lacerta trilineata (9m,10f) 
Lacerta lepida (5m. 6f) 
Lacerta pater (7m.5f) 
Lacerta andreanszkyi ( 1 m,4f) 
Lacerta laevis ( I Om. 1 Of) 
Lacerta danfordi (7m, 5f) 
Lacerta bedriagae (8m.l3f) 
Lacerta mosorensis lOm.lOf) 
Lacerta oxycephala ( 1 Om. 1 Of) 
Algyroides nigropunctatus ( 10m,7f) 
Lacerta perspicillata (9m. 1 If) 
Podarcis hispanica (9m,6f) 
Podarcis m. fiumana (lOm.lOf) 
Podarcis muralis (lOm.lOf) 
Podarcis s. campestris 10m, 100 
Podarcis peloponnesiaca ( 1 9m, 1 1 f) 
Lacerta jayakari (7m, 9f) 
Adolfus alleni (9m,7f) 
Holaspis guentheri (3m, 41") 
Gastropholis echinata (4m) 
Gastropholis tropidopholis ( If) 
Gastropholis vittata ( lm.lf) 
Gastropholis prasina (lm) 
Tropidosaura montana (3m) 
Tropidosaura gularis (lm.lf) 
Tropidosaura essexi (2m) 
Tropidosaura cottrelli ( 1 m) 
Poromera f'ordi (3m,3f) 
Nucras boulengeri (7m. 71") 
Nucras lalandei (4m. If) 
Philochortus intermedius (5m,4f) 
Latastia longicaudata ( 10m,6f) 
Heliobolus lugubris (7m,4f) 
Ichnotropis capensis (9m, 50 
Pseuderemias mucronata ( 12m,60 
Meroles reticulatus (lm,40 
Meroles ctenodactylus (3m. If) 
Meroles cuneirostris (10 
Meroles anchietae (2m. 10 
Pedioplanis lineoocellata (4m,40 
Eremias persica (3m, 5f) 
Acanthodactylus schmidti (12m. 100 
Acanthodactylus scutellatus (10m,30 
Mesalina balfouri (6m,4f) 
Mesalina A', SW Arabia (2m,40 
Mesalina ercolini (10 
Ophisops e. schlueteri (5m, 60 



1.02 


1.03 


.78 


.77 


1.08 


1.02 


.78 


.77 


1.25 


1.13 


.69 


.70 


1.34 


1.26 


.69 


.69 


1.30 


1.24 


.65 


.64 


1.30 


1.23 


.68 


.70 


0.99 


0.81 


.82 


.78 


1.01 


0.88 


.80 


.80 


1.09 


1.03 


.70 


.69 


1.20 


1.20 


.64+ 


.64 


1.14 


1.04 


.71 


.72 


1.11 


1.10 


.74 


.73 


0.96 


0.78 


.73 


.86 


1.26 


1.17 


.66 


.67 


1.27 


1.16 


.67 


.68 


1.23 


1.16 


.71 


.70 


1.17 


1.1 


2 .71 


.74 


1.17 


1.13 


.74 


.73 


1.25 


1.12 


.71 


.74 


1.13 


1.00 


.72 


.74 


1.18 


1.05 


.69 


.71 


1.14 


0.99 


.65 


.67 


1.12 


1.03 


.71 


.71 


1.20 


1.12 


.66 


.65 


1.20 


1.09 


.63 


.64 


1.20 


1.18 


.75 


.72 


0.94 


0.87 


.77 


.78 


1.01 


1.01 


.85 


.80 


1.05 




.77 






1.16 




.74 


1.01 


0.94 


.76 


.78 


1.04 




.77 




0.88 




.8 




1.15 


0.97 


.72 


.77 


1.05 




.71 




1.06 




.77 




1 .35 


1.28 


.75 


.74 


1.03 


1.01 


.72 


.71 


0.82 


0.67 


.79 


.79 


1.34 


1.16 


.60 


.66 


1.29 


1.18 


.61 


.63 


1.58 


1.57 


.53 


.53 


1.38 


1.29 


.64 


.65 


1.81 


1.68 


.51 


.53 


1.73 


1.58 


.60 


.57 


1.7 


1.7 


.60 


.58 




1.61 




.57 


1.74 


1.66 


.62 


.62 


1.49 


1.46 


.64 


.64 


1.38 


1.32 


.68 


.69 


1.37 


1.38 


.58 


.58 


1.42 


1.41 


.58 


.59 


1.34 


1.22 


.63 


.64 


1.20 


1.04 


.69 


.72 




0.96 




.79 


1.51 


1.32 


.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 



72 



E.N. ARNOLD 



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 Takydromus 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 Takydromus. 

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 intermedins, 
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 



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 



0.8 



0.7 



0.6 



0.5 




0.8 



1.0 



1.2 



1.4 



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 



73 



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,Adolfusjacksoni 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 ruhropunctata, 
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 and A 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 1 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- 



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 



E.N. ARNOLD 



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 



tail 



FEMUR 



mesial 

protraction 
abduction 



CRUS 




lateral 

retraction 
adduction 



METATARSAL 
SEGMENT 



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 cms 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. Acanthodact\lus) 



Climbing 
(e.g. L. oxycephala) 



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



Relative length of 
metatarsal bones 

Digits 1-4 

Relative length of meta- 
tarsal + digits 3 and 4 

Size of digit 5 

Shape of digits 3-5 

in lateral view 
Cross section 

of digits 
Shape of phalanges 
Prepenultimate phalanx of 

digits 2—4 markedly shorter 

than contiguous ones 
Claw 
Articulations 

within digits 
Mesial flexibility 

of digits 1-4 



4 longer than 3 



3 longer than 4 



long shorter 

4 markedly 4 not much 

longer than 3 longer than 3 

short, often long 

minaturised 

gently curved ventrally clearly kinked 

or straight 

rounded latero-mesially 

compressed 

robust more slender 

no yes 



long and shallow 
double-headed 

restricted 



short and deep 
simple 

substantial 



NICHE, MORPHOLOGY AND LOCOMOTION IN LACERTID LIZARDS 



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. 



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. 






The pes in ground dwelling lacertids from open situations (Figs 
7a.c, 8a, 9a, 10a ). 

In advanced members of the Armatured clade, UkeAcanthodactylus, 
the whole foot is large and metatarsal bones 1 to 4, and the digits 
arising from these, are especially long and increase successively in 
length. In some instances, such asHeliobolus 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 Ichnotropis capensis. Toes are straight or 
gently curved ventrally when at rest (Fig. 9a) and are rounded in cross 
section ( Fig. 1 0a). The phalanges themselves are robust (Fig. 9a) and 
tend to become steadily shorter distal ly 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 2—4- 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 2-A. 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, 1 0a). 



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



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 



E.N. ARNOLD 





a 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 1 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 



77 






dorsal tendon 



phalanx 



ventral tendon 




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






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 ventri fleeted; 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 1 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. 



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. 
I. troodica, many L. knlzcri. 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 Takydromus 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 



E.N. ARNOLD 



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 1 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. 11a, 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 llb,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 



Table 3 Characteristics of the manus in ground dwelling and climbing 
lacertids (see Fig. 1 1). 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 involv- 
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. 1 lc) 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, penulti- 
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 






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 



E.N. ARNOLD 



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 Teiidae 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 Teius disappears entirely, something that also 
occurs in the ground running agam'id Si tan a (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. 



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. 



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 / 1 000 sec, or filmed at 1 6^48 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 \^\ 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 



$3 



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- 
sagittal^ or somewhat anterolateral^ 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 1^4 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. 1 2b). 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 
anterolateral^, 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 ( 1 2d ). 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 1^1 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 2-A 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 



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 



E.N. ARNOLD 



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 cms, 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 cms 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 cms 
may be brought forwards until it is roughly perpendicular to the 
body with the foot directed anteroposteriorly. Finally, the cms 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 - cms, 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 



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 mnners 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 thmst 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 cms fully forwards. However, they tend 
to carry the body less high than specialised ground-dwellers, partly 
because their limbs are generally shorter and the cms 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 2-4 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. 



femur 



crus 



i metatarsal v » 
j segment 



digits 



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 






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 forboth fore and hind limbs, beingabout 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 \-A. 



86 



E.N. ARNOLD 



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 1-4 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. 1 6). 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. 




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 a running 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. 



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 



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 



87 



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 3-5 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 1. 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 1 and 2 and 4 and 
5, the tendon is displaced away from the joint. This differential 





>^^ 




Fig. 17 Effects of digit kinking and tendon position, a. Fourth hind toe of 
Lucerta 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). 



E.N. ARNOLD 



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 maxi- 
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 



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.LargenandJ. 
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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Bull. not. Hist. Mus. Loud. (Zool.) 64( 1 ): 91-95 



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 5BD, UK. 



SYNOPSIS. Hetereleotris georgegilli, described from six specimens, 1 9.7-22.5 mm SL, is distinguished from congeners by the 
following combination of characters: second dorsal-fin rays 1,10-1 1, usually 1. 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 and//, ymzibarensis. 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 3-221 10; 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. 



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 et 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 et 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 (Ruppell, 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). 



©The Natural History Museum. 1998 



92 



A.C. GILL 




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, 05 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, PC. Heemstra, A.C. Gill, D.G. Smith, 



IFP 



TLCP 





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



M.J. Smale, W. Holleman, P. Clark, et al. 
PCH 95-M30). 



18 May 1995 (field no. 



DIAGNOSIS. Hetereleotris georgegilli is distinguished from conge- 
ners by the following combination of characters: second dorsal-fin 
rays 1, 10-1 1, usually 1,10; 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). 

Description. Dorsal-fin rays VI + 1,10 (1,10 f4; 1,11 fl); anal-fin 
rays 1,9; pectoral-fin pointed with 18/18(16fl; 17 f2; 18 f7) rays, the 
lower 1 (0 f8; 1 f2) 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 1,5; branches 
on first segmented pelvic-fin ray 5/4 (4 flO); branches on second 
pelvic-fin ray 5/5 (4 f4; 5 f5; 6 f 1 ); branches on third pelvic-fin rays 
6/6 (4 fl; 5 f6; 6 f3); branches on fourth segmented pelvic-fin ray 5/ 
5 (3 f3; 4 f4; 5 f3); 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 + 7fl;8 + 7 
f4); upper unsegmented caudal-fin rays 5 (4 fl; 5 f4); lower 
unsegmented caudal-fin rays 4 (4 f2; 5 f3); vertebrae 10 + 17; first 
dorsal pterygiophore formula 3-22 1 1 0; 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 f5; 6 f4; 
7 fl; Fig. 6); lateral scale rows 11/11 (10 f2; 11 f5; 12 fl; 13 f2). 

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, 




SRl^l 



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. 



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 1-5, 
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 



93 



reducing to 1 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 1; 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 1 8.8 ( 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 (1 1.6-14.3); 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//, 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 (10-1 1, usually 10 versus 1 1); 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 from H. georgegilli in having: two 
prominent opercular spines (versus spines lacking); fewer lateral 
scales (4-6 versus 1 0- 1 3 ); 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 1 1 versus 10-11, 



94 



A.C. GILL 



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"S057°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 



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 
10 11 13 18 20 22 23 



27 30 32 



'. apora 


- 


- 


r . georgegilli 


- 


- 


r . poecila 


- 


- 


r . vinsoni 


5 


2 


'. zanzibarensis 


5 


1 



_ 1 



- - 5 



2 1 



2 - 



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;//. georgegilli from surge and tidal-current areas 
in 4-10 m;//. poecila from rock pools in 0-1 m; and//, vinsoni from 
around coral bommies and patch reefs in 0.3-1.9 m. 

TAXONOMIC NOTES. Hetereleotris apora. Hoese & Winterbottom 
(1979) described//, apora (asLioteres 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-M 10 [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 1997.10.24.4-5 (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 f 13. 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//, 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-M 1 [BMNH 1997.10.24.10 



MAURITIAN HETERELE0TR1S 



95 



-11 (2 specs), RUSI 56875 (1), USNM 344318, (2)] and PCH 95- 
M5 [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//, 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 Mahe, 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-M1 1 [USNM 344327 (1)]; PCH 95- 
M18 [BMNH 1997.10.24.14-18(5), RUSI 56877 (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//. 
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 fl9; 18 f6. 



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//. 
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 
Ernest R. Tinkham, A. U.S. Proceedings of the Academy of Natural Sciences of 
Philadelphia 98: 123-218. 

Gill, A.C. & Reader, S.E. 1 992. Fishes, pp. 90-93. 1 93-228. 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. LB. 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 South African gobies and comments on the 
generic relationships and endemism of western Indian Ocean gobioids. Royal 
Ontario Museum, Life Sciences Occasional Paper 31: 1-13. 

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 
Herpelologists Special Publication 1. 

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



Bull. not. Hist. Mus. bond. (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 5BD, UK 

AGUS H. TJAKRAWIDJAJA 

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

CONTENTS 

Introduction 97 

Materials and Methods 98 

Generic Account 98 

Schismatorhynchos Bleeker, 1855 98 

Species Accounts 100 

Key to the species of Schismatorhynchos 100 

Schismatorhynchos heterorhynchos (Bleeker. 1853) 100 

Schismatorhynchos holorhynchos sp. nov 104 

Schismatorhynchos endecarhapis sp. nov 105 

Intrageneric comparisons 107 

Discussion 107 

Annotations to keys of cyprinid genera of the region 108 

Acknowledgements 108 

References 108 



SYNOPSIS. Schismatorhynchos Bleeker. 1 855 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 KalimantanTengah 
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 
comer 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, 1 853), the type 
species, possesses the eponymous rostral cleft. Nukta Hora, 1 942 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: I) 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. 



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 5. 
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 



> The Natural History Museum. 1998 



98 



D.J. SIEBERT AND A.H. TJAKRAWIDJAJA 



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 RainbouYs 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 



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. 1 A- 
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 ofWeber & 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 asGarra, 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 include? 
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. 5. keterorhynchos, MZB unregistered, mm SI; B. S. holorhynchos, USNM 325389. 101.7 mm SI; C. 
S. endecarhapis, MZB 6092, 1 79.0 mm SI: D. Lobocheilos bo, BMNH 1 993.5. 1 9: 1 . 87.0 mm SI; E. Tylognathus diplostomus, BMNH 1 932.2.20:7, 2 1 5.0 
mm SI. ELJ=edge of lower jaw; F=frenulum; LL=Iower 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. IE ) 
and similar to that of Tylognatus nukta (Hora, 1942: Fig. 9b; see 
Reid, 1985:p. 287 for the assignment of Labeo nukta toTylognathus). 
At < 30 mm SI 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. keterorhynchos. 

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 is 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 diagnosisexcludesM/^to 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 [5. 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 5. 
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 



D.J. SIEBERT AND A.H. TJAKRAWIDJAJA 



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 T. nukta 01T. 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 T. 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 (= ITylognathus 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 T. 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 T. 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. 



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 
middle caudal fin-rays S. heterorhynchos 

lb. Snout without horizontal cleft, middle caudal fin-rays not pigmented 
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 SI), [Indonesia], 
Sumatra, Solok, H.C. Schwanenfeld. 

Non-type materials. Sumatra - ZMA 115.911 (5. 175-228 mm 
SI); [Indonesia]; Sumatra, Penetai. E. Jacobson, VII- 19 15. MZB 
4818 (2, 1 19.6-156.6 mm SI); 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; 67.9-7 1 .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 SI); 2) MZB 8601, Station IV, Habitat 2(1, 
1 1 0.4 mm SI); 3) MZB 8602, Station VI.2 (2, 86.9-97.6 mm SI); 4) 
MZB 8603, Station IX, at Muara Suluk (1, 134.0 mm SI); 5) MZB 
8604, Station XIII (5, 85.4-93.8 mm SI); and 6) MZB 8605, Station 
XIV, at Muara Apeang (1, 101.7 mm SI). 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 SI); 3) MZB 8608, Station V (1. 
107.3 mm SI); 4) MZB 869, Station VIII (2, 89.4-96.0 mm SI); and 
5) MZB 8610, Station VI (1; 92.2 mm SI). Sungai Apeang, an upper 
basin tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 
30 Jun 1996: 1) MZB 861 1, Station X.2 (2, 98.6-128.2 mm SI); 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 SI); 
and 2) MZB 8614, Station XVI.2 (3, 97.2-131.0 mm SI). Sungai 
Menjakan, an upper basin tributary of Sungai Sibau; col. Ike 
Ratchmatica and Haryono, 1 Jul 1996: 1) MZB 8615, Station XI. 1 
(1, 132.6 mm SI); and 2) MZB 8616, Station XI.3 (1, 81.4 mm SI). 
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 SI). Sungai Berarap, an upper basin 
tributary of Sungai Sibau; col. Ike Ratchmatica and Haryono; 3 Jul 
1996; MZB 8618, (1, 95.0 mm SI). 

DIAGNOSIS. A species of Schismatorhynchos with a deep horizon- 
tal cleft in snout (S. holorhynchos and 5. endecarhapis without cleft 
in snout); snout, including cleft, heavily tuberculate, tubercles pyra- 



SCHISMATORHYNCHOS REVISION 



101 




Fig. 2 Photograph of a large (A. ZMA 1 15.91 1. 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 conical, multi-cuspi- 
date tubercles; S. endecarhapis with simple, conical tubercles); 
dorsal fin with eight branched fin-rays, falcate, anterior two princi- 
ple fin-rays very elongate in larger individuals (S. endecarhapis with 
1 1 branched rays in dorsal fin); distinct, dark lateral band extending 
to distal tips of middle rays of caudal fin (lateral band of 5. holo- 



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

Description. Material in a 70-225 mm SI size range was avail- 
able for study. No material was available below 68 mm SI 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. 5. heterorhynchos, MZB 8612, 136.4 mm SI; B. S. holorhynchos, FMNH 68550, 77.6 mm SI; 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 1st 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:Ml = 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 5. heterorhynchos changes with size (Fig. 2). Smallest 



specimens examined have a relatively round body. Between 100 mm 
SI and 150 mm SI body depth and compression increases. Above 170 
mm SI 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 SI, 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'/2 scales above lateral line to dorsal origin; AVi 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 Vi of scale row above lateral line scale row 
and upper x h 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 
5.9±0.8 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 
16.1±1.1 12.4-18.9 



24.5± 1.4 20.5-27.0 
8.7±0.9 6.9-10.2 
23.1+3.4 18.3-30.8 
5.7±1.0 4.1- 7.7 
47. 7±1. 4 45.5-50.2 
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 



103 



Table 2 Lateral I 
Schismatorhync 


nc 
10s. 


scale count 


frequencies 


for species 


of 










30 


31 


32 




33 


34 


S. heterorhynchos 
S. holorhynchos 
S. endecarhapis 




4 
4 


12 
50 


18 

9 

3 




4 

3 
13 


3 



DISTRIBUTION. Studied material of 5. 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. 




LNSL 



Fig. 4 Log-log plot (natural logarithms) of the relationship between 
height of the dorsal fin and standard length; ♦ = S. heterorhynchos, 
LnDFl = -3.2 + 1.44LnSl, SE of coefficient = 0.05, R 2 = 0.96, n = 36; 
▲ = S. endecarhapis, LnDfl = -1.7+ 1 .09LnSl, SE of coefficient = 
0.07, R 2 = 0.92, n = 25; and • = S. holorhynchos, LnDfl = -1 .9 + 
1.12LnSl, SE of coefficient = 0.04, R 2 = 0.99, n = 13. 



9+ 



0°- 




121 c 
+9* 



9°4- c 
94 



Fig. 5 Localities from which Schismatorhychos material was examined in this study; ♦ = S. heterorhynchos, A ■ 
• = 5. holorhynchos; target symbols = type localities. 



+ 9 
121° 



: S. endecarhapis, and 



104 



D.J. SIEBERT AND A.H. TJAKRAWIDJAJA 



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 IB, 3,5, 6) 

Schismatorhynchus heterorhynchus; Inger & Chin, 1962: 86 

HOLOTYPE. USNM 325389 (101.7 mm SI); Malaysia; Sarawak; 
confluence of Batang Balui and Batang Kerumo; 02°22'N 1 13°45'E; 
col. L. Parenti, K. Luhat, and A. Among; 3-VIII- 1991; field no. LRP 
91-28. 

Paratypes. USNM 346637 (12 including 1 cleared and counter 
stained, 39.5-78.8 mm SI); data as for holotype. 

Non-type MATERIALS. Borneo (Kinabatangan River basin, Sabah, 
Malaysia) - FMMN 68548 (28, 28.3-34.8 mm SI); small stream 1 
mi. above Sungei Tabalin Besar, Sta. 1; col. R. Inger and P.K. Chin; 
2 1 April 1 956. FMNH 68549 ( 1 , 49.3 mm SI); Deramakot Camp, hill 



stream; col. R. Inger; 2 May 1956. FMNH 68550 (5, 42.7-79.3 mm 
SI); 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, 30.3^9.4 mm SI); 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 SI); Baleh River, creek entering northern 
bank approx 5 km E of Sut River; 2°2'N 1 13°07'E; col. L. Parenti et 
at.; 25 Jul 1991. USNM 324978 (2, 33.5-35.5 mm SI); Baleh River, 
stream entering river opposite Sekolah Negara Bawai; 2°0'N 
1 13°03'E; col. L. Parenti etai; 24 Jul 1991. USNM 325387 (2, 59.2- 
59.5 mm SI); Baleh River, creek entering southern bank approx. 20 
km E of Sut River; 2°01'N 1 13°06'E; col. L. Parenti et al.\ 24 Jul 
1991. USNM 325388 (2, 67.6-68.7 mm SI); Batang Balui, Batang 
Tamn were it enters Bantan Balui; 02°22'N 1 13°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 1 13°46'E; col. L. Parenti etai: 3 
Aug 1991. USNM 325411 (28, 38.7-77.6 mm SI); Batang Balui. 
stream near mouth; 2°20'N 1 13°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 SI) and a small (B. USNM 325890, 43.6 mm SL) specimen of 5. 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 



5. endecarhapis n=45 



Vertebrae 

Precaudal vertebrae 
Caudal vertebrae 
Peduncular vertebrae 
Dorsal fin position 
Anal fin position 
Branched dorsal-fin rays 
Ribs 



31 ±0.0 

15.9±0.23 15- 
15.1+0.23 15- 

5.4±0.50 5- 
8.0±0.23 7- 

18.9±0.23 18- 

8±0.0 

12.3+0.47 12-13 



32.0+0.10 31-32 

16.0+0.17 15-16 

16.0+0.14 16-17 

5.8±0.48 5- 7 

7.9±0.30 7- 8 

19.0±0.46 19-20 

8.0+.0.10 7- 8 

10.3+0.51 9-11 



33.0+0.15 32-33 
16.9±0.32 16-17 
16.1+0.36 15-17 

5.8±0.44 5- 6 

8.0±0.0 
20.1 ±0.32 20-21 
11.0±0.40 10-12 
12.7±0.45 12-13 



rays in dorsal fin (5. endecarhapis with 1 1 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 (5. 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 M w:Ml 
= 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 (Io 
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 ofS. 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'/2 scales above lateral line to dorsal origin; 4'/2 
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 



in reference to the new species' snout, which lacks the deep cleft 
found in the snout of its sister species, S. heterorhynchos. 

DISTRIBUTION. Materials ofS. 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 1 14°44.103'E); hook and line; col. D.J. Siebert, A.H. 
Tjakrawidjaja and O. Crimmen; 15-18 Jul 1992; field no. DS-12- 
1992. 

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 SI); 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 1 1 1 °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 
SI); 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 SI); 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 SI); Barito 
River at Desa Muara Laung; 0°34.576'S 1 14° 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; 0°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. 



1 1 1°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 1 1 1°40'E; rotenone; T.R. Roberts; 24 July 1976; field no. 
Kapuas 1976-27. 

DIAGNOSIS. A species of Schismatorhynchos with 1 1 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, 5. 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 (5. 
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:Ml 
= 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 Io 1 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 1 1 branched fin-rays (1 individual with 10, 
1 individual with 12), origin well in advance of pelvic fins. Margin 



SCHISMATORHYNCHOS REVISION 



107 



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 Vi scales above lateral line to dorsal origin; 4Vi 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 1 st 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. lb), usually a scale above and below lateral 
line darkened along with 1 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 5. 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- 
metry information of Table 1. Complete separation of the three 
species is achieved in the two dimensions of Axis 1 and Axis 2. 
Axis 1 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 5. endecarhapis. and 
S. holorhynchos, well before the tubercles undergo obvious enlarge- 
ment. 




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 1 = 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 7,2,1 73. p< 0.0001. 




-2.8 -0.2 

AXIS1 

Fig. 9 Graphical joint summary of the selected morphometries of species 
of Schismatorhynchos with 0.75 confidence ellipses of samples 
{S. heterorhynchos = ♦; S. holorhynchos = •; 5. 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 < 0.000 1 . 



108 



D.J. SIEBERT AND A.H. TJAKRAWIDJAJA 



DISCUSSION 



Including Schismatorhynchos endecarhapis and 5. 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 is 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 5. 
holorhynchos is probably more closely related to 5 1 . heterorhynchos 
than it is to S. 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. ID). 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 all, 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 



rays in the dorsal fin. Schismatorhynchos endecarhapis, with 1 1 
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 

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 
Schismatorhynchos 

b. lower and upper lips continuous around corner of lower jaw. 

aa. Dorsal with 10-18 branched ray Labeo 

bb. Dorsal with 8-9 branched rays 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. 1 09); lower 
jaw with a symphysal knob; lower lip reflected backwards,but not 
separated from jaw Barbichthys 

27b. Suborbital bones not enlarged; no symphysial knob on lower jaw ; lower 
lip distinctly separated from lower jaw go to * 

*a. lower and upper lips not continuous around coiner of lower jaw 
Schismatorhynchos 

*b. lower and upper lips continuous around corner of lower jaw 

go to 28 

28a. 10-18 Vi branched dorsal rays go to 29 

28b. 8-9 Vi branched dorsal rays 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, DC 
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 



109 



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Crassispirinae). A.V. Sysoev and J.D. Taylor. 

Foregut anatomy and relationships of the Crassispirinae 

(Gastropoda, Conoidea). Y.I. Kantor, A. Medinskaya and 

J.D. Taylor. 1997. Pp 1-92. £40.30 

The lucinid bivalve genus Cardiolucina (Mollusc: Bivalvia: 
Lucinidae); systematics, anatomy and relationships. J.D. Taylor 
and E.A. Glover. 

A new species of water mouse, of the genus Chibchanomys 
(Rodentia: Muridae: Sigmondontinae) from Ecuador. P.D. 
Jenkins and A. A. Barnett. 

A new species in the asterinid genus Patiriella (Echinodermata: 
Asteroidea) from Dhofar, southern Oman: a temperate taxon in 
a tropical locality. A.C. Campbell and F.W.E. Rowe. 
Morphological observations on Oncaea mediterranea (Claus, 
1863) (Copepoda: Poecilostomatoida) with a comparison of 
Red Sea and eastern Mediterranean populations. R. Bottger- 
Schnack and R. Huys. 1997. Pp. 93-147. £40.30 



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CONTENTS 

1 A revision 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 

DarrellJ. Siebert and Agus H. Tjakrawidjaja 



\ li! .ii ii v Mi 
ZOOLOGY SERIES 
Vol.64, No. 1, June 1998