Gerrhopilus Fitzinger, 1843

Pyron, Robert Alexander & Wallach, Van, 2014, Systematics of the blindsnakes (Serpentes: Scolecophidia: Typhlopoidea) based on molecular and morphological evidence, Zootaxa 3829 (1), pp. 1-81 : 43-44

Gerrhopilus Fitzinger, 1843

Type species. Typhlops ater Schlegel, 1839

Species content. Gerrhopilus andamanensis, Ge. ater, Ge. beddomii, Ge. bisubocularis, Ge. ceylonicus, Ge. depressiceps, Ge. floweri, Ge. fredparkeri, Ge. hades, Ge. hedraeus , Ge. inornatus, Ge. manilae, Ge. mcdowelli, Ge. mirus, Ge. oligolepis, Ge. thurstoni , and Ge. tindalli .

Diagnosis. Gerrhopilus can be distinguished from all other typhlopoids by the numerous distinct sebaceous glands (cephalic papillae) covering the head shields (not just beneath the sutures at the base of head shields as in all other typhlopoids). Small to moderate-sized (total length 87–331 mm), moderate-bodied (length/width ratio 17–89) snakes with 16–28 scale rows (usually without reduction), total middorsals 190–780, short to long tail (1.5–5.1% total length) with 9–29 subcaudals (length/width ratio 1.0–4.0), and with or without an apical spine. Dorsal and lateral head profile either rounded or pointed, sometimes with a ventral beak, sagittate rostral narrow to moderate (0.26–0.63 head width), nasals usually in contact behind rostral or overlapping one another, preocular in contact with subocular or second and third supralabials, eye present as a dark spot or small eye with distinct pupil, subocular often present, T-II or T-V SIP, and postoculars 1–4. Lateral tongue papillae present; left lung absent, tracheal lung unicameral or paucicameral (with 8–35 pockets), cardiac and right lungs unicameral; testes unsegmented; hemipenis eversible, lacking retrocloacal sacs; rectal caecum small (0.2–4.4% SVL), and rarely absent. Coloration of dorsum uniformly brown, reddish-brown, chocolate-brown or black; venter normally lighter, usually golden brown, light brown or tan; snout, supralabials, chin, cloacal region and/or tail tip white or yellow.

Phylogenetic definition. Includes the Most Recent Common Ancestor (MRCA hereafter) of Gerrhopilus hedraeus and Ge. mirus and all descendants thereof, and all species more closely related to Ge. ater than to Cathetorhinus melanocephalus .

Etymology. Possibly from the Greek for reed (gerrhon), referring to the slender body, and the Latin for hairlike appendage (pilus), referring to the cephalic papillae.

Distribution. India (plus Andaman & Cocos Islands), Sri Lanka, Thailand and the East Indies ( Philippines, Indonesia, Papua New Guinea).

Remarks. Taylor (1919) suggested that the Philippine species Typhlops manilae was allied with Gerrhopilus based on the presence of a subocular, a character common in Gerrhopilus (Table 2). However, Hedges et al. (2014) argued that it was more similar to Malayotyphlops . Given that the subocular is common in Gerrhopilus but absent in Malayotyphlops , and no other character unambiguously allies it with Malayotyphlops (Table 2), we follow Taylor's suggestion and move it to Gerrhopilus . Hedges et al. (2014) corroborated Wallach & Pauwels (2004) in moving the south Indian T. thurstoni to Gerrhopilus on the basis of a T-II SIP, a common characteristic of other south Indian Gerrhopilus (Table 2).