Eutropis ashwamedhi ( Sharma, 1969 ) Sharma, 1969

Srinivasulu, Chelmala, Srinivasulu, Bhargavi, Srinivasulu, Aditya & Seetharamaraju, Midathala, 2016, No longer supple? Molecular phylogeny suggests generic reassignment of Lygosoma ashwamedhi (Sharma, 1969) (Reptilia: Scincidae), Zootaxa 4127 (1), pp. 135-148 : 138-146

Eutropis ashwamedhi ( Sharma, 1969) comb. nov.

Riopa ashwamedhi Sharma, 1969

Lygosoma ashwamedhi ( Sharma, 1969)

This species is here transferred to the genus Eutropis Fitzinger, 1843 based on morphological characters and molecular phylogenetic analysis.

Diagnosis. Eutropis ashwamedhi comb. nov. can be distinguished from the genus Lygosoma by the presence of supranasals, and all known congeners based on the following characters: adult snout–vent length 20–32.1 mm; tail length 32–42.7 mm; short snout (less than 17% of head length); midbody scale rows 28–32; scales weakly keeled; ventral scales 47–49; supralabials 7–8; supranasal present, rectangular, in medial contact; Toe IV lamellae 13–15; ear openings oval shaped with four lobules on anterior margin. The coloration of the dorsum is generally goldenbrown, marked with 13 dark brown longitudinal bands starting at the nuchals on the back and ear openings on the sides, fading from the attachment of the hindlimbs to the middle of the tail. The head scales are bordered with dark brown and variably marked at the centre. The limbs and the distal part of the tail are golden-brown dorsally. The ventral surface of the body is creamish-ivory.

Description (NHM.OU.REP.4-2010). A well-preserved adult female; SVL 32.1 mm, TL 42.7 mm; snout short (IN/IO ratio 0.28), obtuse, slightly shorter than the lower jaw ( Fig. 3 ); nostril laterally oriented, oval, situated closer to snout-tip than to orbit (EN/ES ratio 0.54) ( Fig. 3 E–F); head relatively short, longer than wide, HL 6.5 mm, HW 4.8 mm (HL/HW ratio 1.35), slightly flattened, HD 3.9 mm (HL/HD ratio 1.67); rostral broad, projecting well onto snout, not in contact with frontonasal ( Fig. 3 A–B); posterior border of rostral semicircular; supranasals rectangular, in contact with one another; frontonasal trapezoid, wider than long; prefrontals moderate, not in contact with each other; frontal elongated, arrow-head shaped, wider anteriorly, smaller than combined lengths of frontoparietals and interparietal; frontoparietals in broad contact ( Fig. 3 A–B); interparietal single, slightly longer than frontonasal; parietals separated by interparietal, scales bordering the outer margin equal in size; four supraoculars; no contact between supraocular I and frontal; only supraocular II completely in contact with frontal ( Fig. 3 A–B, 3E–F); five supraciliaries; nostrils located in the nasals; postnasal absent; loreal squarish, one in number; two presuboculars, separating supralabial IV and anterior part of supralabial V from lower eyelid ( Fig. 3 E–F); seven supralabials (larger part of supralabial V in contact with the orbit of eye); two postoculars; temporals smooth; one pair of nuchals ( Fig. 3 A–B); seven infralabials ( Fig. 3 E–F); first pair of chin shields in contact, one scale separates second pair of enlarged chin shields, three scales separate third pair of chin shields ( Fig. 3 C–D); enlarged chin shields contact infralabials; external ear opening larger than adjacent scales, oval, with 4 lobules on anterior margin, oriented towards the posterior, the upper two lobules larger than the lower ones ( Fig. 3 E–F); pupil rounded; lower eyelid scaly, shows faint presence of a semi-transparent scaled disc; scales on upper eyelid small, numbering 10, middle ones being larger than others; scales on upper row of lower eyelid small, numbering 14 ( Fig. 3 E–F); tongue moderate; teeth small and pointed.

Body relatively slender, BW 7.2 mm (BW/SVL ratio 0.22); head indistinct from neck and from body; 42 paravertebral rows; 49 ventrals; skin fragile; body scales cycloid, with 2 feeble keels; 32 transverse scale rows at midbody; 58 subcaudals; on dorsum, keels start from the nuchals; scales on flanks with weak keels; scales on venter smooth, uniform in size except the median ventral scales being relatively enlarged than those on the flanks; each ventral scale shows at an angle two faint notches on the anterior margin and one notch on the posterior margin; preanals enlarged, lateral pair of preanals overlap median preanal; tail long (TL/SVL ratio 1.33), tip acute, tail base wider than rest of tail, gradually tapering to a point; median row of subcaudals not enlarged relative to adjacent scales. Limbs relatively short; pentadactyl and clawed; scales on limbs weakly bicarinate; lamellae obtusely tuberculate and enlarged; adpressed limbs reach up to middle of the forearm; lamellae under Finger I–6; II–9; III–12; IV–12; V–9; lamellae under Toe I–7; II–9; III–13; IV–14; V–11.

Colouration (in life) ( Fig. 1 A). Dorsum and forehead light golden-brown; head patterned; torso with distinct black lines; venter, including gular region unpatterned yellowish-ivory. Head scales from frontoparietals to nuchals bordered throughout with dark brown with the median being marked variably as follows: faint minute brown spots clumped together looking like a single brown spot in the middle of the frontonasals and prefrontals, two brown spots on frontoparietals, one large inverted ‘V’ shaped spot on the frontal, unequal horizontal bar like markings on the parietals, interparietal has four brown spots in the middle, nuchals with horizontal bars and spots. Each scale on the dorsum and sides has dark brown margin, due to which the animal’s dorsum seems lined with 12 light goldenbrown bands flanked by 13 dark brown bands. The bands start from the ear openings on the sides and after nuchals on the dorsum. The lateral-most dark bands on the sides starting from the ear opening are the thinnest; the first dark band above the ear opening is the widest; the second dark band above the ear opening bifurcates in to two at an angle of attachment of the forelimbs. The vertebral band is the lighter band. The banding fades from the attachment of the hindlimbs to the mid of the tail. The posterior part of tail is light golden-brown. Dorsal surfaces of limbs pale golden-brown, scales bear pale brown borders. Undersurface of body, limbs and tail creamish-ivory. Tongue grey.

Colouration (in preservative) ( Fig. 1 B). Excepting general dulling, colouration remains unchanged; pupils less discernible.

Measurements (in mm). New Material. AG 21.3; BW 7.2; DBE 3.9; DFE 2.8; EaL 1.0; EaW 1.1; EE 5.4; EN 1.9; ES 3.4; ED 2.7; FL 3.7; HD 3.9; HL 6.5; HW 4.8; IN 0.9; IO 3.2; NE: 6.67; SED: 8.34; SN: 1.06; SVL 32.9; TD: 3.46; TL 42.7; TW: 4.01; TBL 4.8.

Phylogenetic relationships. Genetic analysis based on the 12S and 16S rRNA gene sequences recovered Eutropis ashwamedhi comb. nov. nested within a clade of endemic lined skinks of India, sister to E. beddomii ( Fig. 4 ). These in turn are sister to the species pair E. nagarjuni + E. trivittata . Relationships observed among all sampled lined skinks were well supported by high posterior probabilities; however, the relationship between E. ashwamedhi and E. beddomii remains less well resolved, and should be corroborated with analyses of additional loci. Eutropis ashwamedhi differs from E. beddomii in having four or five large, undivided scales in the middle of the lower eyelid.

Ecological and distributional notes. The new material was collected from Jaggayapeta (N: 16 O 51'41", E: 80 O 05'03"E; 55 m elev.), Krishna district, Andhra Pradesh, during the day, from under a rock in open scrub jungle earmarked to be converted into an open mine ( Fig. 5 A–C). The following reptile species were found in sympatry here: Agamidae— Calotes versicolor , Sitana ponticeriana ; Gekkonidae— Hemidactylus cf. brookii ; Hemidactylus frenatus ; and Scincidae— Eutropis carinata , Lygosoma punctata , Lygosoma vosmaeri . This species has previously been collected from: 3 km S (N: 16 O 32'24", E: 79 O 21'36"; 160 m elev.) of Vijayapuri South, Guntur District, Andhra Pradesh; Anupu (N: 16 O 32'42", E: 79 O 15'40"; 253 m elev.), Guntur District, Andhra Pradesh; Eddenmotu Hills (N: 16 O 28'37", E: 79 O 17'13"; 391 m elev.), 3 km S of Pullareddygudem, Guntur District, Andhra Pradesh; Fringimotu Hills (N: 16 O 27'55", E: 79 O 14'19"; 250 m elev.), 5 km SW of Pullareddygudem, Guntur District, Andhra Pradesh, Nandikonda Valley (N: 16 O 36'01", E: 79 O 17'46"; 170 m elev.), near Vijayapuri North, Nalgonda District, Telangana State ( Fig. 6 ). The habitat of these locations is predominantly rocky scrub forest ( Sharma, 1969; Srinivasulu et al., 2005; Srinivasulu & Srinivasulu, 2013).

Comparison. Seventeen nominal species of Eutropis have been reported from India, including 14 species from the mainland and the rest from the Andaman and Nicobar Islands ( Uetz & Hosek, 2015). Eutropis ashwamedhi ( Sharma, 1969) comb. nov. was compared with all the 17 congeners from India, and can be distinguished from others basing on the following unique characters ( Table 2): lower eyelid scaly with transparent disc divided in to two or more parts (vs. lower eyelid with an undivided, more or less, transparent disc as in E. bibronii Gray , E. dissimilis Hallowell and E. innotata Blanford ; and lower eyelid scaly as in E. multifasciata Kuhl , E. tytleri Theobald , E. andamanensis Smith , E. rugifera Stoliczka , E. beddomii Jerdon , E. quadricarinata Boulenger , E. trivittata Hardwicke & Gray , E. nagarjuni Sharma , E. gansi Das , E. clivicola Inger, Shaffer, Koshy & Bakde , E. rudis Boulenger ). Among the others with which it shares the lower eyelid scaly with transparent disc divided in to two or more parts character, E. ashwamedhi can be distinguished based on its small size (SVL to 32 mm vs. SVL to 125 mm in E. carinata Schneider , SVL to 75 mm in E. macularia Blyth and SVL to 75 mm in E. allapallensis Schmidt ) and being distinctly lined (13 dark lined vs. faintly lined as in E. carinata Schneider , E. macularia Blyth and E. allapallensis Schmidt ).

Species Characters

Scales round Dorsal scales Keeled Lamellae under fourth toe; Smooth/Keeled

the mid body (numbers)

A. Forms having lower eyelids with a transparent disc

Eutropis bibronii 28–30 Strongly (5–7) 14–20; Keeled, feebly Eutropis dissimilis 34–38 Strongly (2–3) 12–16; Smooth Eutropis innotata 32–34 Moderately (3–5) 17–18; Keeled, feebly B. Forms having scaly lower eyelids, central scales much enlarged than others

Eutropis allapallensis 26–30 Strongly (3–7) 15–18; Keeled, obtusely Collected more than half a century ago by B. Nath and I. N. Maligi of Zoological Survey of India from a mere five locations in the Krishna river basin near the Nagarjunasagar Dam and described in 1969, Ashwamedh’s Skink Lygosoma ashwamedhi ( Sharma, 1969) remains virtually unknown. Between 2008 and 2010 we conducted herpetofaunal surveys in areas leased out for mining activities in the Krishna river basin of Andhra Pradesh and in one such surveys a specimen of this species was collected. Despite several efforts no further specimens were obtained (pers. obs., Datta-Roy et al., 2014). Originally described as a species under the genus Riopa Gray, 1839 , it was shifted to the genus Lygosoma Hardwicke and Gray, 1827 (See Das 1996; Das et al., 1998; Srinivasulu & Das, 2008).

The genera Lygosoma Hardwicke and Gray, 1827 and Mabuya Fitzinger, 1843 (sensu lato, now as Eutropis Fitzinger, 1843 ) differ from each other not only on internal cranial features, but also on external characteristics. The genus Lygosoma can be differentiated from the other two genera by the absence of the supranasals ( Smith, 1935). The genus Riopa Gray, 1839 has been synonymized with Lygosoma Hardwicke and Gray, 1827 basing on morphological ( Greer, 1977) and molecular phylogeny ( Datta-Roy et al., 2014). In the new material and the type series of Eutropis ashwamedhi comb. nov., only the second supraocular is in broad contact with the frontal and the interparietal separates the parietals ( Figs. 2 A, 3A–B) which is a eutropine character.

The discovery of the new material of this rare species ( Srinivasulu & Srinivasulu, 2013, Datta-Roy et al., 2014) has provided us with an opportunity to conduct detailed study on its morphology and morphometrics, and to sequence its 12s and 16s rRNA genes, leading to its phylogenetic identity. Our analysis is in concordance to the recent phylogeny of squamate reptiles ( Pyron et al., 2013), and shows the genus Eutropis and genus Lygosoma forming two distinct clades. The present study suggests that Eutropis ashwamedhi comb. nov. is an integral part of the Indian endemic eutropine radiation including E. beddomii , E. trivittata and E. nagarjuni , all of which are characterized by large-sized bodies with prominent lines on the dorsum.

Figures

FIGURE 1. Photographs of Eutropis ashwamedhi comb. nov. A) Adult colouration, in life (NHM. OU. REP. 4 – 2010), B) Adult colouration, in preservative (NHM. OU. REP. 4 – 2010). Scale 10 mm.

FIGURE 2. Paratype of Riopa ashwamedhi Sharma, 1969, now Eutropis ashwamedhi comb. nov. [ZSI 21175, collected from Nandikonda Valley, Vijayapuri North, Nalgonda District, Andhra Pradesh (now in Telangana State), on 8.8. 1962 by B. Nath; badly damaged] in the collection of the National Zoological Collection, Zoological Survey of India, Kolkata, India. A) Dorsal and B) Ventral aspects (Photo courtesy Kaushik Deuti). Scale 10 mm.

FIGURE 3. Head of Eutropis ashwamedhi comb. nov. (NHM. OU. REP. 4 – 2010). A & B) Dorsal view, C & D) Ventral view, and E & F) Lateral view. See text for abbreviations used for scales.

FIGURE 4. Maximum clade credibility topology estimated from Bayesian Inference (BI) of the combined 12 S and 16 S rRNA gene dataset using Tamura-Nei nucleotide substitution model with Invariant Sites (TN 93 + I, BICc = 6285.3; ln L = - 2660.216). Values at the nodes are posterior probability values. Lerista kalumbura and Larista bouganvillii were used as outgroup taxa.

FIGURE 5. Habitat of the location at Jaggayapet, Krishna District, Andhra Pradesh, India from where the recent specimen of Eutropis ashwamedhi comb. nov. was collected. A) Place of collection, B) General habitat of the area, and C) View of the habitat wherein open-cast mining activity has already commenced.

FIGURE 6. Map depicting the location of Eutropis ashwamedhi comb. nov. in Andhra Pradesh and Telangana, India; blue circles—past records, red circles—new record.