Dravidoseps, Agarwal & Thackeray & Khandekar, 2024

Agarwal, Ishan, Thackeray, Tejas & Khandekar, Akshay, 2024, A non-adaptive radiation of viviparous skinks from the seasonal tropics of India: Systematics of Subdoluseps (Squamata: Scincidae), with description of a new genus and five cryptic new species, Vertebrate Zoology 74, pp. 23-83 : 23

Dravidoseps gen. nov.

Type species.

Lygosoma pruthi Sharma, 1977

Chresonymy.

Riopa - Sharma (1976, 1978)

Lygosoma - Das (1996)

Subdoluseps - Freitas et al. (2019), Ganesh et al. (2021)

Diagnosis.

Medium-sized skinks (adult SVL <58 mm; n = 89), original tail equal to or slightly longer than body. Dorsal scales on body and tail smooth, cycloid, imbricate; ventrals similar except marginally larger on pectoral and precloacal region; scales on lateral tail base smooth or tricarinate; 62-70 scales in paravertebral rows; 26-32 scales around mid-body; 61-73 ventral scales (rarely 76, n = 1/89); 8-12 enlarged precloacal scales (rarely 13, n = 1/89); and 18-23 scales round the tail. Supranasals in contact with each other behind rostral (rarely not in contact, n = 1/89); single frontonasal; prefrontals relatively small, widely separated on midline; frontal elongate, bell-shaped; four supraoculars; three supraoculars in contact with frontoparietal (rarely two, n = 4/89); frontoparietal divided; interparietal diamond-shaped, eyespot in posterior projection; parietals large, in medial contact posterior to interparietal; 2-4 nuchals, either in contact behind parietals or separated medially by 1-3 paravertebral scales. Nasal divided; two loreals; a single pre-supraocular; two preoculars (rarely three, n = 4/89); and a single sub-preocular (rarely absent, n = 5/89); 6-8 supraciliaries (rarely nine, n = 1/89); lower eyelid with enlarged, transparent central window; a single post-supraocular and postocular; and three or four sub-postoculars (rarely five, n = 3/89); a single primary, two secondary (rarely three, n = 1/89), and three tertiary (rarely four, n = 1/89) temporals. Six or seven supralabials and infralabials; fourth or fifth supralabial elongate, below eye; one or two post-supralabials; 1-3 ear lobules; three enlarged pairs of chin shields. Pentadactyl; limbs well-developed; subdigital lamellae unpaired, smooth to weakly keeled; 4-7 lamellae under digit I of manus and pes, 9-12 lamellae under digit IV of manus and 12-17 lamellae under digit IV of pes (rarely 18, n = 1/89). Viviparous, litter size 2-4. Dorsum light coconut to dark chocolate brown; thick dark band from rostrum to tail speckled with light spots; supralabials with a white streak; males with yellow on lower parts of forebody and flanks, sometimes extending onto belly; venter white with some darker markings (Fig. 9 ).

Dravidoseps gen. nov. differs from Subdoluseps by the presence of a transparent central window in the lower eyelid (versus no transparent central window in the lower eyelid), by the presence of an open secondary palate (versus a closed secondary palate) and by being viviparous (versus oviparous) ( Freitas et al. 2019; Zimin et al. 2021).

Content.

Dravidoseps goaensis comb. nov., Dravidoseps pruthi comb. nov., Dravidoseps nilgiriensis comb. nov., and five species described below.

Phylogenetic definition.

This genus comprises species that share a more recent common ancestor with Dravidoseps pruthi comb. nov. than with Subdoluseps bowringii .

Etymology.

A combination of the Sanskrit ‘Dravida’, referring to the original inhabitants of southern India and Sri Lanka, and the Ancient Greek ‘seps’, for a snake-like creature that has been previously used in skink generic names (e.g. Erens et al. 2017; Freitas et al. 2019). The gender of the genus is masculine and the suggested common name is Indian leaf-litter skinks.

Distribution and natural history.

The three known species and five unnamed lineages (described below) are distributed in peninsular India, including the northern Western Ghats, central and southern Western Ghats, the edge of the Mysore Plateau and isolated massifs in Tamil Nadu (Fig. 1 ). Members of the genus are diurnal (sometimes seen moving in the litter soon after dark) and are terrestrial and partially fossorial.

Figures

Figure 1. Elevation map showing sampling localities from peninsular India. Stars indicate type localities (neotype locality shown for Dravidoseps goaensis comb. nov., original type locality is close to the southernmost point), light blue D. jawadhuensis sp. nov., dark blue D. srivilliputhurensis sp. nov., light green D. kalakadensis sp. nov., dark green D. pruthi comb. nov., red D. gingeeensis sp. nov., yellow D. nilgiriensis comb. nov., pink D. tamilnaduensis sp. nov., and grey, D. sp. Kalrayan (colour scheme representing species is the same as Figs 3 - 6), black squares unsampled previously known localities. The approximate extent of the Central Western Ghats (CWG), Northern Western Ghats (NWG), and Southern Western Ghats (SWG) are shown; major hill ranges and features are marked by bold white text, within the Western Ghats: AG, Agasthyamalai; AN, Anaimalai; DV, Devarmalai; N, Nilgiris; PG, Palghat Gap; PL, Palani; and outside the Western Ghats: BR, Biligirangan; J, Jawadhu; K, Kollimalai; KR, Kalrayan; mm, Male Mahadeshwara; MP, Mysore Plateau; PC, Pachaimalai; PM, Palamalai; S, Sitteri; SR, Sirumalai; T, Tirupati; V, Velikonda; Y, Yercaud; YL, Yelagiri. Inset, global distribution of Dravidoseps gen. nov. (brown) and Subdoluseps sensu stricto (green). Dravidoseps goaensis = Riopa goaensis (see main text).

Figure 9. Dravidoseps gen. nov. species in life: A D. pruthi comb. nov. (neotype, NRC-AA- 1291); B D. goaensis comb. nov. (neotype, BNHS 2567); C D. nilgiriensis comb. nov. (ZSI-R- 28604); D D. gingeeensis sp. nov. (holotype, NRC-AA- 8273); E D. jawadhuensis sp. nov. (holotype, NRC-AA- 8274); F D. kalakadensis sp. nov. (holotype, NRC-AA- 8275); G D. srivilliputhurensis sp. nov. (holotype, NRC-AA- 8279); and H D. tamilnaduensis sp. nov. (holotype, NRC-AA- 8286). Photos by Akshay Khandekar (B-D, F-H) and Ishan Agarwal (A, E).