Vol.5, No.9, 993-996 (2013) Natural Science
Distribution and chromosomal va riation in the
scincid lizard genus Lygosoma (Reptilia: Squamata)
in Thailand
Varanya Aranyavalai1*, Kanok Lertpanich2, Warawut Chulalaksananukul3
1Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok, Thailand;
*Corresponding Author: varanya.a@chula.ac.th
2Department of Agricultural Technique, Faculty of Agricultural Development and Resources Management, King Mongkut’s Institute
of Technology Ladkrabang, Bangkok, Thailand
3Department of Botan y, Faculty of Science, Chulalongkorn University, Bangkok, Thailand
Received 15 July 2013; revised 15 August 2013; accepted 22 August 2013
Copyright © 2013 Varanya Arany avalai et al. This is an open access article distributed under the Creative Commons Attribution Li-
cense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
The distribution of the scincid lizard genus Ly-
gosoma in Thailand was studied and recorded
on a map. In addition, the studies on chromo-
somes of Lygosoma bowringii, L. khoratense
and L. quadrupes were examined. The karyotype
was determined for each individual on the basis
of at least 10 well spread cells. L. bowringii and
L. khoratense showed the same diploid number
of 2N = 32 and identical chromosome morphol-
ogy. The fundamental number (N.F.) equals 48.
The karyotype of L. quadrupes is almost identi-
cal to that of L. bowringii, but differs from the
latter in having a telocentric p air 9. Thus, the N.F.
value equal to 46. No sex chromosome hetero-
morphisms is evident.
Keywords: Di stribution; Chromosome; Skinks;
Lygosoma; Thailand
Skinks are a hyper-diverse group of reptiles, contain-
ing more than 1000 species ranging from temperate to
tropical regions on all continents but Antarctica [1,2 ]. Of
these, about 12 genera are recognized in Thailand [3] and
probably some skinks are waiting for description. The
genus Lygosoma described by Hardwicke & Gray, 1827
in family Scincidae has a long and complicated nomen-
clatural history. The common name, writhing skinks, re-
fers to the way these stubby-legged animals move, sn ake-
like but slower and more awkward. The limbs are par-
tially or almost completely reduced (varying from com-
pletely developed four or five digital to hardly noticeable
unidactylous or adactylous limbs). They are truly cos-
mopolitan, distributed in Africa, Australia, South and
Southeast Asia, Polynesia, and Central America. These
skinks are seldom seen on the surface of the soil or leaf
litter. Lygosoma feeds on insects and small invertebrates.
Most species lay eggs, but a few are live-bearers. Very
few record of this genus was subsequently made, and our
knowledge about this secretive skink and its geographi-
cal distribution remains minimal. Currently, most of the
skink’s data are focused on taxonomic status. There are
very few records of biology of skinks, making it difficult
to available in applied works such as concentrating on
captive breeding, and conserving skink species of pure
genetic quality. Cytotaxonomic studies are especially mea-
ger, despite their possible great contributions to the un-
derstanding of the divergence and relationships of the
species. This is due to the paucity of chromosomal data,
especially for the species of Lygosoma. The aim of this
research is to study sp ecies distribution, chromosome nu m-
ber and describe karyotypes of the scincid genus Ly -
gosoma in Thailand. Results revealed the presence of
considerable intraspecific ch romosomal variations within
the genus.
Field surveys were conducted in Thailand, including
Bangkok, Phra Nakhon Si Ayutthaya, Nakhon Nayok,
Chai Nat, Nakhon Sawan , Uttaradit, Phetchab un , Ph ich it,
Kamphaeng Phet, Tak, Sukhothai, Phrae, Lampang, La m-
phun, Nan, Chiang Mai, Mae Hong Son, Chiang Rai,
Saraburi, Nakhon Ratchasima, Burirum, Khon Kaen,
Ubon Ratchathani, Nongkhai, Nakhon Phanom, Suphan-
Copyright © 2013 SciRes. OPEN ACCESS
V. Aranyavalai et al. / Natural Science 5 (201 3) 993-996
buri, Kanchanaburi, Chachoengsao, Rayong, Chan th a bu r i ,
Chumphon, Ranong, Suratthani, Nakhon Si Thammarat,
Phatthalung, Songkhla, Phang-nga, Krabi, Phuket, Trang
and Satun provinces. Specimens were collected by p itfall
traps and using the visual encounter survey method. De-
tailed localities of Lygosoma were recorded and plot-
ted in a map. Specimens of Lygosoma bowringii, L.
khoratense, and L. quadrupes were karyotyped in the
laboratory. They were injected intraperitoneally with
0.1 ml of colchicines solution (2 mg/ml) per gram bo-
dy weight, 16 hr before being sacrificed. Metaphase
mitotic cells taken from femur bone marrow were treat-
ed with 0.075 M hypotonic KCL solution for approxi-
mately 30 min, followed by fixation in 1:3 glacial acetic
acid:absolute methyl alcohol. Mitotic chromosome
preparations were made by an air-dry method and stained
in 10% Giema solution for 10 - 15 min. The karyotype
wa s det ermin ed from at least 10 well-spread cells. Termi-
nology for chromosomal description follows Green and
Sessions [4]. The experimental protocol was approved by
the Animal Care and Use Committee of Faculty of Sci-
ence, Chulalongkorn University (Protocol Review No.
3.1. Distribution
Three species of skinks in genus Lygosoma, including
L. quadrupes, L. bowringii, and L. khoratense were found
at 28 locations during the field surveys. Localities of
them were shown in Figure 1 and Table 1.
3.2. Description of Species
Lygosoma quadrupes
A slender and very elongate skink with four very short
limbs but still has five digits. The ear-opening is very
small, narrow and partly covered with scales. The lower
eyelid is nearly yellow-white, movable and covered by
two rows of small scales. There is a single frontoparietal
and nasal but the postnasal is absent. The rostral is little
wider than high, while the frontonasal is broader than
long, forming suture with rostral, frontal, and anterior
loreal. The anterior loreal is higher but narrower than the
second loreal. The prefrontals are small and widely sepa-
rated. The frontal is little longer th an its d istan ce from tip
of snout, about as long as single frontoparietal, but smaller.
The interparietal is little smaller than frontal and en-
closed by parietals. There are 24 to 26 scalerows around
middle of body. The color is gray-brown to brown with
dark longitudinal lines, usually visible on edges of all
scalerows, continued onto tailed. The top of head is dar ker
than the body (Figures 2(a) and (b)).
Figure 1. Distribution of Lygosoma quadrupes, L. bowringii,
and L. khoratense in Thailand.
Figure 2. Lygosoma quadrupes (a) from Kanchanaburi Prov-
ince; (b) from Chai Nat Province.
Lygosoma bowringii
A little skin k with short limbs and cannot to uch unless
the body is flexed. The small supranasal scales are pre-
Copyright © 2013 SciRes. OPEN ACCESS
V. Aranyavalai et al. / Natural Science 5 (201 3) 993-996
Copyright © 2013 SciRes.
Table 1. Locations of skinks in genus Lygosoma observed in the field surveys.
Species No. Province Location
Lygosoma quadrupes
Chai Nat
Pramongkutklao H o s p i t a l a n d C o l l e ge of Medicine
King Mongkut's Institute of Technology Ladkrabang
Amphoe Mueang
Amphoe Kaeng Hang Maeo
Amphoe Song Phi Nong
Amphoe Thong Pha Phum
Lygosoma bowringii
Phra Nakhon Si Ayutthaya
Nakhon Nayok
Chiang Mai
Nakhon Ratchasima
Ubon Ratchathani
Amphoe Mueang
Wangtakrai, Amphoe Mueang
Amphoe Laplae
Amphoe Sam Ng a o
Amphoe Wiang Sa
Amphoe Fang
Amphoe Thong Pha Phum
Amphoe Sanam Chai Khet
Amphoe Tha Takiap
Amphoe Kaeng Hang Maeo
Amphoe Khlung
Amphoe Laem Sing
Amphoe Soi Dao
Amphoe Kaeng Khoi
Amphoe Sikhio
Amphoe Khong Chiam
Amphoe Phato
Amphoe Kapoe
Amphoe Ko Yao
Amphoe Na Yong
Amphoe La-ngu
Lygosoma khoratense 28 Nakhon Ratchasima Amphoe Sikhio
sent and the tympanum is deep ly sunk below th e external
ear opening. The frontonasal is large, laterally touching
the first loreal. The prefrontals are widely separated and
the suture between frontal and frontonasal is nearly a
straight line. The length of frontal is greater than its dis-
tance from tip of snout but less than length of combined
parietals and frontoparietals. The frontoparietal is divided
and the interparietal is enclosed by parietals. There are
two loreals, anterior higher and narrower than the seco nd.
It has smooth or faintly keeled scales, a scaled lower
eye li d , a n d a di s ti n ct iv e dark flank band with white s po t s ,
red behind the arm and yellow bellow. There are 30 sca-
lerows around neck and 31 scalerows around middle of
body. The ventral scales are larger than the laterals but
smaller than the dorsals (Figures 3 (a) and (b)).
Figure 3. Lygo som a bowringii (a) from Satun Province; (b)
from Chanthaburi Province.
are 28 scalerows around neck and 32 to 34 scalerows
around middle of body. The short thick tail suddenly ta-
pers at the tip. The dorsum is brownish, each scale with a
dark brown edge and a vague dark spot at its base. The
flanks are lighter than the dorsum while the venter is pale
grey, and the subcaudals are darker. The scales of head
are slightly darker edges. It is found only in Thailand.
Lygosoma khoratense
An elongate skink with small widely separated penta-
dactyl limbs. The rostral is wider than high and part visi-
ble above considerably is longer than suture between
supranasals. The latter scales are fused to the nasals ante-
riorly. The frontonasal is about twice as broad as long
touching the first loreal. The prefrontals are small and
widely separated, leaving a broad suture between frontal
and frontonasal. The first lo real is higher and shorter than
the second. The frontoparietal are paired. The interparie-
tal is small, enclosed behind by parietals. The ear-open-
ing is very small with small lobules proj ecting from ante-
rior border. Snout scales are somewhat thickened. There
3.3. Chromosome Numbers and Karyotypes
Karyotypes of Lygosoma bowringii and L. khoratense
seem to be identical with each other when treated with
Giemsa: both species have 2N = 32 chromosomes form-
ing three size groups (Figures 4(a) and (b)). Of these,
pairs 1 to 4, composing the largest group, are metacentric
macrochromosomes. There is a size discontinuity between
pairs 4 and 5. The second size group consists of four pair
metacentric chromosomes (pairs 5, 6, 7, and 9), gradu-
ally reducing in size. Of the remainder composing the
smaller size, pair 8 is submetacentric, whereas the smallest
V. Aranyavalai et al. / Natural Science 5 (201 3) 993-996
Figure 4. Karyotypes of (a) Lygosoma bowringii (male) from
Chanthaburi Province, and (b) Lygosoma khoratense (male)
from Nakhon Ratchasima Province. Bar equals 10 µm.
pair appears to be telocentric. The fundamental number
(N.F.) is calculated as 48. The karyotype of L. quadrupes
(Figure 5) is almost identical to that of L. bowringii and
L. khora t ens e , but differs from the latter in having a te-
locentric pair 9. Thus, the N.F. value equals 46. In addi-
tion, in these three Ly gosoma species, secondary con-
strictions are evident on the shorter arms of pair 1 or the
longer arms of pair 2 or both. No sex chromosome het-
eromorphisms are evident.
During our field surveys, three species of skinks in
genus Ly gosoma were found. The microhabitats of them
are cryptozoic and partially fossorial and are found under
dead tree trunks, in dead wood and in loose, humid soil
where they glid e with agility. L. bowringii, L. khoratense
and L. quadrupes hitherto examined have karyotypes
sharing many similarities with each other such as the
diploid chromosome number (32), large metacentricity in
pairs 1 to 4 and the distinct size-gap between pairs 4 and
5. So, these populations seem to be lacking in chromo-
some changes that could act as reproductive barriers.
However, because speciation in lizards is not always as-
sociated with chromosome repatterning (see [5] for re-
view), and considering that the 2N = 32 karyotype is
plesiomorphic for skinks [6], the lack of karyotypic dif-
ferentiation does not necessarily indicate that the “L.
bowringii” and “L. khora ten se ” fo r ms b e lon g to th e s ame
biological species. Therefore, further C-banding studies
are needed for the inference of its derivation process. In
addition, future detailed an alyses inv olving karyotypes of
the remaining species in genus Ly gosoma are needed to
test in order to clarify intraspecific chromosomal varia-
tions within this genus.
Figure 5. Karyotype of Lygosoma quadrupes (male) from
Chainat Province. Bar equals 10 µm.
This study reported the distribution of the scincid liz-
ard genus Lygosoma in Thailand. Comparison on chro-
mosomes of Ly gosoma bowringii and L. khoratense
showed the same diploid number of 2N = 32 and identi-
cal chromosome morphology. The karyotype of L. quad-
rupes is almost identical to that of L. bowringii, but dif-
fers from the latter in having a telocentric pair 9. There is
no evidence of heteromorphic sex chromosomes.
This research was supported by the TRF/BIOTEC Special Program
for Biodiversity Research and Training Grant (Grant no. MRG 5080366).
Varanya is also indebted to Dr. Ratchata Phochayavanich, Mr. Chat-
traphas Pongchareon, and Mr. Kasem Theingtham for helping with
field sampling.
[1] Matsui, M. (1992) Systematic zoology, Vol. 9, vertebrates
IIb2, Reptilia II. Nakayama-Shoten, T ok yo.
[2] Zug, G.R., Vitt, L.J. and Caldwell, J.P. (2001) Herpetol-
ogy. Academic Press, London.
[3] Nabhitabhata, J., Chanard, T. and Chuaynkern, Y. (2000)
Checklist of amphibians and reptiles in Thailand. Office
of Environmental Policy and Planning Bangkok, 80-92.
[4] Green, D.M. and Sessions, S.K. (1991) Nomenclature for
chromosomes. In: Green, D.M. and Sessions, S.K., Eds.,
Amphibian Cytogenetics and Evolution, Academic Press,
San Diego, 431-432.
[5] King, M. (1981) Chromosome change and speciation in
lizards. In: Atchley, W.R. and Woodruff, D.S., Eds., Evo-
lution and Speciation, Cambridge University Press, Ca m-
bridge, 262-285.
[6] Caputo, V., Odierna, G. and Aprea, G. (1994) A chromo-
somal study of Eumeces and Scincus, primitive members
of the Scincidae (Reptilia, Squamata). Bolletino di Zo-
ologia, 61, 155-162. doi:10.1080/11250009409355876
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