A fossorial lizard with forelimbs only: Description of a new genus and species of Malagasy skink (Reptilia: Squamata: Scincidae)

7 Pages·2003·1.5 MB·

Current Herpetology (1): 9-15, June 22 2003
(C) 2003 by The Herpetological Society of Japan
A Fossorial Lizard with Forelimbs Only: Description of a New
Genus and Species of Malagasy Skink (Reptilia: Squamata:
Scincidae)
SHUICHI SAKATA* AND TSUTOMU HIKIDA
Department of Zoology, Graduate School of Science, Kyoto University, Kitashirakawa-
Oiwakecho, Sakyo, Kyoto 606-8502, JAPAN
Abstract: A new genus and species of fossorial scincine lizard is described
from northeastern Madagascar. This species, having an elongated body and
eyes covered by scales, lacking external ear openings and pigmentation through-
out the body, resembles Cryptoscincus and Voeltzkowia. However it differs
from these or any other scincid genera known to the present in having small but
distinct forelimbs, each with four stout claws, and complete lack of hind limbs.
Key words: New genus; New species; Scincidae; Madagascar; Fossorial; Limb
reduction
Ampijoroa, Ankarafantsika Strict Nature
INTRODUCTION
Reserve, northwestern Madagascar (Fig. 1),
Seven endemic genera of the subfamily yielded two of specimens an apparently unde-
Scincinae (Squamata, Scincidae) are known scribed skink. This skink differs from any
from Madagascar, and most of them consist of known scincids in having forelimbs only. We
fossorial or semifossorial species (Angel, 1924; thus describe it as genus a new and species.
Brygoo, 1979, 1980a-d, 1981a-c, 1984a-d,
1985; Mocquad, 1909). Recent herpetological
METHODS AND MATERIALS
surveys on Madagscar led to discoveries of
many new species (Raxworthy and Nussbaum, The with fixed was specimen 10% formalin,
1993; Nussbaum and Raxworthy, 1995; Andre- preserved in 75% ethanol, and deposited in
one and Greer, 2002; Sakata and Hikida, the Zoological Univer-of Collection the Kyoto
2003). Due to their largely secretive habits, sity Museum (KUZ). The following measure-
however, many species of these and related ments were taken with dial calipers and
genera are thought to remain undiscovered. recorded to the nearest 0.1mm: snout-vent
Ecological surveys, carried out by Japanese length (SVL), tail length, head length (snout
ornithologists and herpetologists in collabora- tip to posterior margin of parietals), snout
tion with their Malagasy counterparts in length (snout tip to anterior corner of eye),
head width (the widest point of temporal
region), and midbody width. Vertebral
* Corresponding author. Tel:[phone]-
4074; Fax:[phone]. characters were determined by radiographs
E-mail address:[email protected] (Softex M-60, Softex Co.).
10 Current Herpetol. (1) 22 2003
Generic diagnosis
The genus a member new is of the subfamily
Scincinae (Greer, 1970). It is distinguished
from other all taxa in this group by the follow-
combination ing of characters states derived in
(polarity for each of these characters was
inferred as relative to Eumeces, the putative
primitive genus of the family: Greer and
Broadley, 2000). Body highly elongated
(SVL 11.6-14.0 times head length) with 53
presacral vertebrae; longer original tail slightly
than SVL; snout pointed, jaw lower counter-
sunk; neck indistinguishable externally; body
scales smooth and transparent without pig-
mentation; 20 longitudinal scale rows at mid-
body. Forelimb small (approximately 4.7% of
SVL) with indistinct fingers and four stout
no claws; hind limbs, shallow groove in their
position in other prefrontals scincines; absent;
sharply nasal pointed, triangular, positioned at
notch V-shaped of rostral; positioned nostril at
anterior tip of nasal; frontonasal as large as
frontal; frontoparietal absent; loreal single;
supraoculars two; superciliaries and movable
lower eyelid absent; eye covered with two
FIG. 1. Map of Madagascar, showing location
oculars; supralabials six; infralabials five,
of Ampijoroa, the type locality of Sirenoscincus
anterior three higher than posterior two;
yamagishii sp. nov.
external ear opening covered by scales, but
small ear groove visible through transparent
We defined the scales covering the eyes as postmental scale; single.
ocular(s). Terminology for the other charac-
Sakata ters follows and Hikida (2003). Species diagnosis
The the is diagnosis species same as that for
Sirenoscincus yamagishii gen. et sp. nov. the genus.
2 Figs. and 3
Description of holotype
Holotype Adult female. Head much narrower than
KUZ R50922, mature female; Ampijoroa, body; snout pointed; lower jaw countersunk;
Ankarafantsika Strict Nature Reserve, north- nostril anterolaterally oriented, visible from
Madagascar western 20'S, 48'E: 46 (16 Fig. 1), above; ear openings absent, small ear groove
100m; collected by A. Mori, M. Hasegawa, visible through transparent scales covering it;
and Ikeuchi, I. November 7 1999. neck not distinct; body elongated, greatly with
presacral 53 vertebrae; body and tail round in
Paratype cross section; forelimbs small, with indistinct
KUZ R50823, mature female, from the fingers absent. hind and four limbs stout claws;
same locality as the holotype, collected by G. Rostral scale large, overlapping nasals,
Razafindrakoto, as a "dead on the road" supranasals and first supralabials; nasal
November specimen, 11 1999. sharply pointed and triangular, positioned in
SAKATA & HIKIDA-NEW SKINK WITH FORELIMBS ONLY 11
FIG. 2. Holotype of Sirenoscincus yamagishii sp. nov. (KUZ R50922) in life, with its autotomized tail.
the V-shaped notch of rostral, overlapping preocular posteriorly; preocular single, over-
supranasal and first supralabial; nostril located lapped by second supralabial, overlapping first
in anterior tip of nasal, in contact with rostral; supraocular, first ocular, and third supralabial;
supranasals two, each overlapped by first presubocular absent; supraoculars two, over-
supralabial, overlapping loreal and frontona- lapped by two oculars below, overlapping
sal, right overlapping left; frontonasal over- frontal and parietal above, and primary and
lapped laterally by loreal, overlapping frontal upper secondary temporals posteriorly; ocu-
and first supraocular posteriorly; prefrontals lars two, covering eye, overlapped by third
absent; frontal as large as frontonasal, over- supralabial, overlapping supraoculars, primary
lapped laterally by first supraocular, overlap- temporal and fourth supralabial; postsubocu-
ping interparietal and a pair of parietals lar absent; primary temporal one, overlapped
posteriorly; frontoparietal absent; interpari- by fourth supralabial, overlapping upper and
etal triangular, with two longer sides converg- lower secondary temporals and fifth suprala-
ing to a bluntly rounded apex posteriorly, bial; upper secondary temporal about half as
overlapping parietals; transparent spot on long as parietal, overlapping lower secondary
interparietal absent; parietals two large, qua- temporal, nuchal, and anteriormost scale of a
drangular, left overlapping right behind inter- lateral body scale row; lower secondary tem-
parietal, each overlapped by first and second poral overlapped by fifth supralabial, overlap-
supraoculars, overlapping upper secondary ping sixth supralabial and anteriormost scales
temporal and first nuchals; two nuchals on belonging to lateral body scale rows; mental
left, one on right; supralabials six, three preor- slightly larger than postmental, overlapping
bital, one subocular and two postorbital; loreal postmental and first infralabials; postmental
single, quadrangular, as long as second suprala- overlapped by first infralabials, overlapping
bial, overlapped below by first and second the first pair of chin shields; three pair of chin
supralabials, overlapping first supraocular and shields, first pair in contact, second separated
12 Current Herpetol. (1) 22 2003
by one scale, and third separated by three
scales; five infralabials, second highest, third
body widest; and with covered tail smooth cyc-
loid scales; position of hind limb insertion in
other having scincines a patch of scales, small
followed by short groove; preanal scales two,
slightly larger than ventral body scales, right
left; overlapping tail broken when captured.
Measurements of holotype (mm)
SVL, 82.5; original tail length, 84.4; head
length, 7.1; snout length, 4.0; head width, 4.2;
midbody width, 5.2; length of forelimb exclu-
sive of claws, 3.8; fourth finger length, 0.6;
distance between nostrils, 1.8.
Coloration
In life, head, body, forelimbs and tail
uniformly pinkish white; snout somewhat
paler than the other portion of head; black
pigmentation of eye visible; autotomized tail
somewhat whiter than original portion; scales
transparent, white. without claws pigmentation;
After preservation, pinkish coloration faded to
uniformly white, and then to yellowish slightly
after year half in alcohol.
Variation
In paratype, head slightly depressed; fore-
broken; limb tail SVL, length, 86.9; 53.7; head
length, 6.20; snout length, 3.0; head width,
5.4; midbody width, 4.6; distance between
nostrils, 1.7. This had specimen more nuchals
than holotype-two in three left, right. in
Etymology
The generic name derived is from the Latin
words, siren (mermaid) and scincus (skink),
FIG. 3. Dorsal (A), lateral (B) and ventral (C) referring to the unique body shape of the type
of views head, ventral view of cloacal region (D), species with forelimbs only. The specific
and forelimb left of the (E) holotype of Sirenoscin-
epithet is dedicated to Dr. Satoshi Yamagishi,
yamagishii cus sp. nov. (KUZ R50922). Abbrevia-
who was a professor of Kyoto University and
tions are: 1°, primary temporal; 2°, secondary tem- the project leader of Ecological Surveys in
poral; cl, claw, cs, chinshield; eg, ear groove; ey, eye;
Ampijoroa, Ankarafantsika Strict Nature
f, frontal; fn, frontonasal; i, interparietal; il, inflala-
Reserve, which in both of the type specimens
bial; l, loreal; m, mental; n, nuchal; na, nasal; pa,
were obtained.
parietal; pm, postmental; po, preocular; oc, ocular;
r, rostral; sl, supralabial; sn: supranasal; so, supraoc-
ular.
SAKATA & HIKIDA-NEW SKINK WITH FORELIMBS ONLY 13
Natural history the genus Amphiglossus; A. astrolabi, A.
The holotype was found under the leaf litter reticulatus, and A. waterloti (Brygoo, 1979,
during a night survey. The collectors first 1980a-d, 1981a-c, 1984a-d, Raxworthy 1985,
found an autotomized tail which was still and various nussbaum, degrees showing 1993),
moving on the leaf litter. Then they searched of reduction of limbs (from partial reduction
around there and captured the holotype. The of digits on forelimb or hind limb to the
paratype was collected as a dead body on the complete loss of both limbs), eyes, and ear-
road. Additionally three tails obviously belong- openings (Table 1). Among the eight genera,
ing to the present species ware obtained as Amphiglossus seems to be most primitive in
stomach contents of two colubrid snakes, that it usually has four pentadactyl limbs,
Liophidium torquatum and Dromicodryas movable eyelids, and external ear openings.
bernieri. These two snake species are consid- Three genera, Voeltzkowia, Cryptoscincus,
ered to be terrestrial (Mori et al, unpublished and Sirenoscincus, are obviously extremely
observation). Probably Sirenoscincus yamag- adapted to that fossorial in life their bodies are
ishii is a common prey item for such terrestrial elongated, and eyes and ear openings are
snakes around the type locality. covered by scales. Pigmentation in scales is
also lost in all the species of these genera
for exept three of species Voeltzkowia.
DISCUSSION
assigned formerly of Voeltzkowia, species Two
All Malagasy scincine lizards known to the to the subgenus Grandidiernina, have no
forelimbs and reduced hind limbs. The other
present are fossorial or semifossorial exept
for three aquatic or semi-aquatic species of three species of and Voeltzkowia a species of
TABLE 1. Comparisons of the Malagasy scincineg enera. Numerals indicatneu mbers of digitso n fore-
limbsa nd hind limbs. Symbols:+, present;-,a bsent;b t,b utton-liksec ale;n b, nub; st,s tyliform.
14 Current Herpetol. (1) 22 2003
the monotypic genus Cryptoscincus (C. mini- scincid lizards: description of nine new species,
mus) lack both forelimbs and hind limbs. In notes with on the morphology, reproduction and
contrast, Sirenoscincus has tetradactyl fore- taxonomy of some previously described species
limbs, but lacks hind limbs. This genus quite is (Reptilia, Squamata, Scincidae). J. Zool. Lond.
similar to Voeltzkowia in a number of scale 258: 139-184.
characters, but different from the latter in the F. 1924. une Sur forme de nouvelle Lezard, ANGEL,
combination of reduced limbs, suggesting its en provenance de Madagascar, appartenant au
independent derivation from a four-limbed genre Grandidierina Bull. de Scincides). (Famille
ancestor. Mus. natn. Hist. nat. Paris. 30: 450-452.
It is generally assumed that in Scincidae the E. R. BRYGOO, 1979. Systematique des lezards
limb loss occurred first in the forelimbs (Gans, scincides de la region malagache. I. Scelotes
1975). Sirenoscincus offers a first obvious trivittatus (Boulenger, 1896) nov. comb. synon-
exception to these schemes. Another possible ime de Scelotes trilineatus Angel, 1949. Bull.
exception was exhibited by Pseudoacontias Mus. natn. Hist. nat. Paris. Ser. 4, 1. sec. A. 4:
menamainty, which, while lacking hind limbs, 1115-1120.
has rudimentary, button-like traces of fore- E. R. BRYGOO, 1980a. Systematique des lezards
limbs. The bipedid amphisbaenians also have de scincides la region malagache. Amphiglos-II.
prominent forelimbs and lack hind limbs. sus astrolabi Dumeril Bibron, Gongylus et 1839;
From the shape of forelimbs that resemble polleni Grandidier, 1869; Gongylus stimpffi
those of moles, this group of lizards probably Boettger, 1882, et Scelotes waterloti Angel,
uses the forelimbs for digging. However the Mus. Bull. natn. 1930. Hist. nat. Paris. 4, Ser. 2.
function of the forelimbs of Sirenoscincus is sec. A. 2: 525-539.
still unknown, since they seem to be too small E. R. BRYGOO, 1980b. Systematique des lezards
for digging. The small but distinct forelimbs in scincides de la region malagache. III. Les
Sirenoscincus may have a function for mating. Acontias" de Madagascar: Pseudoacontias Bar- "
boza du Bocage, Paracontias 1889, Mocquard,
Pseudacontias 1894, Hewitt, 1929, et Malacon-
ACKNOWLEDGMENTS
tias Greer, 1970. Bull. Mus. natn. Hist. nat.
We are grateful to A. Randrianj afy, F. Paris. 4, 2. A. Ser. 905-918. sec. 3:
Rakotondraparany, and other staff of the Parc E. R. BRYGOO, 1980c. Systematique des lezards
Botanique et Zoologique de Tsimbaizaza Amphiglos-la malagache. region de scincides IV.
(PBZT) for their cooperation. We are also sus reticulatus (Kaudern, 1922) nov. comb.,
much indebted to F. Andreone for valuable troisieme espece du genre; ses rapports avec
comments on our manuscript, to E. R. Brygoo Amphiglossus waterloti (Angel, 1920). Bull.
and S. Sengoku for literature, to M. Hori for Mus. natn. Hist. nat. Paris. Ser. 4, 2, sec. A. 3:
facilities for autoradiography, and to A. Mori, 905-918.
M. Hasegawa, I. Ikeuchi, and G. Razafindra- E. R. BRYGOO, 1980d. Systematique des lezards
koto for collecting precious specimens. T. scincides de la region malagache. V. Scelotes
Hikida is especially grateful to S. Yamagishi for praeornatus Angel, de synonyme Scelotes 1938,
providing opportunities to visit Madagascar. l. s. frontoparietalis (Boulenger, 1889). Bull.
Our research was supported in part by a Grant- Mus. natn. Hist. nat. Paris. Ser. 4, 2. sec. A. 4:
in-Aid from the Japan Ministry of Education, 1155-1160.
Science, Sports, Culture and Technology (Over- E. R. BRYGOO, 1981a. Systematique des lezards
seas Research No. 11691183 to S. Yamagishi). scincides de la region malagache. VI. Deux
Scincines nouveaux. Bull. Mus. natn. Hist. nat.
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