Lygosoma siamense Siler, Heitz, Davis, Freitas, Aowphol, Termprayoon & Grismer, 2018

Qi 1, Shuo, Ren *, Jin-Long, Wang, Zeng, Yang, Hao-Cong & Jiang, Ke, 2022, On the occurrence of Lygosoma siamense Siler, Heitz, Davis, Freitas, Aowphol, Termprayoon & Grismer, 2018 (Squamata, Scincidae) in China, Herpetozoa 35, pp. 51-58 : 51

Lygosoma siamense Siler, Heitz, Davis, Freitas, Aowphol, Termprayoon & Grismer, 2018

Lygosoma siamensis Siler, Heitz, Davis, Freitas, Aowphol, Termprayoon & Grismer, 2018, J. Herpetol., 52 (3): 339, figs 4-5. Holotype: FMNH 177496 (field no. EHT 1390; figs 4, 5), adult male, collected on 7 June 1956 in Thailand, Pattani Province by E. H. Taylor.

Lygosoma chalcides - Boulenger, 1887: 340 (in part).

Lygosoma quadrupes - Smith, 1935: 290 (in part); Taylor, 1963: 1049; Honda et al. 2000: 453; Ziegler et al. 2007: 401; Bourret, 2009: 264 (in part); Wagner et al. 2009: 4; Das, 2010: 240 (in part); Geissler et al. 2011: 1169 (in part); Geissler et al. 2012: 56; Datta-Roy et al. 2014: 165; Grismer et al. 2018: 534.

Lygosoma siamensis - Siler et al. 2018: 339.

Lygosoma siamense - Freitas et al. 2019: 19.

Etymology.

The species name siamense was derived from the exonym “Siam”, a term formerly used as the name of Thailand. The name was chosen in recognition of Thailand as the center of the species’ known distribution ( Siler et al. 2018).

The grammatical gender of the generic nomen Lygosoma Hardwicke & Gray, 1827 has been confused in the literature where it was treated as both feminine ( Siler et al. 2018) or neutral ( Freitas et al. 2019). The nomen Lygosoma is probably based on the Greek nouns " lygos "and " sōma ", meaning “supple-bodied”, and the gender of this nomen is neutral. Consequently, the ending of Lygosoma siamensis provided by its original description should be modified as " siamense ".

Common names.

Siamese Supple Skink (in English); 泰国蝘蜓 ( Tài Guó Yán Tíng) (in Chinese).

Description of specimens from China.

Main description according to an original tail adult specimen ( SYS r002573, Fig. 2 ), the scale count data of other three damaged tail subadult specimens ( CIB 118520-118522) are given in parentheses. Mensural data of all voucher specimens are listed in Table 3 .

Body small, slender, SVL 72.2 mm; head small, weakly differentiated from neck, roughly equal in width to body, HL 6.1 mm, HW 4.7 mm, HD 3.6 mm; snout slightly pointed, rounded in dorsal and lateral profile; head scales large, smooth, SNL 42.6% HL; external ear opening small, transverse diameter slightly larger than longitudinal diameter; eyes small, ED 21.3% HL, 86.7% END; body moderately depressed, nearly uniform in thickness, MBW 126.8% MBD; scales smooth, glossy, imbricate; longitudinal scale rows at midbody 27 (24-27); paravertebral scale rows 119 (115-119); axilla-groin scale rows 89 (92-95); limbs short, diminutive, pentadactyl; Finger III lamellae five, Toe IV lamellae seven; FLL 5.7% AGD, 4.4% SVL; HLL 10.9% AGD, 8.4% SVL; original TL 56.0 mm, SVL/TL=1.29, tail nearly as wide as body, gradually tapered towards end, TW 78.8% MBW.

Rostral wider than high, in contact with first supralabials and nasals laterally, frontonasal dorsally; frontonasal wider than long, single, in contact with nasal and first loreal laterally, prefrontal and frontal posteriorly; nostril ovoid; supranasals present; postnasals small, triangular-shaped; prefrontals small, widely separated, contacting loreals laterally, first superciliary and frontal posteriorly; frontal large, its anterior margin in broad contact with frontonasal, contacting first two supraoculars laterally; four supraoculars; frontoparietals fused into single large scale, in contact with all four supraoculars laterally and parietals and interparietal posteriorly; interparietal somewhat triangular-shaped, eyespot present posteriorly; parietals in broad contact medially behind interparietal; enlarged nuchals absent; two loreals contacting supralabials; supralabials six, first and sixth largest, fourth and fifth subocular; two preoculars, lower much larger than upper; uninterrupted superciliaries six, first one large, in contact prefrontal anteriorly, first supraoculars dorsally; subocular scale row complete, in contact with supralabials; lower eyelid bearing scales; postoculars two; primary temporals two; secondary temporals two, larger than primary temporals; infralabials six, first two contacting postmental, first smaller than second; mental wider than long, in contact with first infralabial laterally, postmental posteriorly; postmental large, single; two pairs of large chin-shields, first pair in contact, second pair narrowly separated by single medial scale; scales on limbs smaller than body scales; single row of supradigitals (Figs 2 - 4 ).

Coloration in life.

Four specimens ( SYS r002573, CIB 118520, CIB 118521, CIB 118522) from China share similar coloration and pattern. Dorsal surface of head, body, limbs and tail brown, dark brown longitudinal lines present on edges of scales and continuing onto tail. Darker pigmentation present on central part of head; ventral surface of body and tail pale pink; iris dark brown.

Ecological notes.

All four specimens were collected during the day, beneath flowerpots, leaf litter substrates or other surface material. Their reduced limbs are folded alongside body during rapid locomotion ( Das 2010), whereas they are unfolded when slowly crawling.

Diet and reproductive habits remain poorly known. Nevertheless, a large number of ants were observed where the specimens were collected, and probably served as their main food source, which was similar to the habitats as inferred from Das (2010: 83, plate 33). Smith (1935) reported the reproductive habits in stating "A female kept by me in Bangkok laid three eggs on May 27th measuring 9 by 5 mm. in size. The young were born on June 28th and measured 48 mm. in total length, the head and body measuring 26 mm".

Figures

Figure 2. A. The general aspect of the adult male specimen of Lygosoma siamense (SYS r 002573) from Sanya, Hainan, China in life; B. Scalation and coloration characters of the head of the same individual.

Figure 4. The general aspect and close-up views of the adult male specimen of Lygosoma siamense (CIB 118520) from Sanya, Hainan, China, prior to preservation. A. Dorsolateral view of body; B. Ventral view of body; C. Dorsal view of head; D. Ventral view of head; E. Left side view of head; F. Right side view of head. Scale bar: 5 mm.