Cathetorhinus Duméril & Bibron, 1844

Type species. Cathetorhinus melanocephalus Duméril & Bibron, 1844

Species content. Cathetorhinus melanocephalus .

Diagnosis. Cathetorhinus can be distinguished from all other typhlopoids by the combination of a T-II SIP and absence of preocular (fused with nasal). Small-sized (total length 183 mm), slender-bodied (length/width ratio 92) snakes with 18 scale rows throughout, 525 total middorsals, moderate tail (2.7% of total length) with 20 subcaudals (length/width ratio 2.5), and minute apical spine. Dorsal head profile bluntly rounded, lateral profile pointed with a ventral rostral keel that terminates in a blunt point, large oval rostral (0.71 head width), eye discernible as a faint eyespot, and postocular single. Coloration of head in preservative is blackish-brown, dorsum tan with lighter venter.

Phylogenetic definition. This genus is currently monotypic, but would include any newly discovered species more closely related to Cathetorhinus melanocephalus than to Gerrhopilus ater .

Etymology. Unclear; likely refers to keeled, pointed condition of snout, from the Greek for perpendicular (cathetos) and having such a nose (rhinus).

Distribution. Unknown. Collected during the Baudin voyage (1800–1804), which made landfall at the Azores, Cape of Good Hope (South Africa), Mauritius, W Australia, and Timor. Timor seems the most likely origin based upon these possible localities and their ophiofaunas, though one author suggested a potential origin from Mauritius (Cheke 2010).

Remarks. The genus Cathetorhinus is resurrected here from the synonymy of Ramphotyphlops (Hedges et al. 2014) . Previous authors considered Typhlops melanocephalus Typhlopidae incertae sedis, including Dixon & Hendricks (1979), Hahn (1980), and McDiarmid et al. (1999). The type and only known specimen (MNHN 138), which is in poor condition, has been re-examined by Wallach & Pauwels (2008), and does not fit the definitions of any other typhlopoid genera. Those authors resurrected Cathetorhinus . The combination of a T-II SIP and 18 dorsal scale rows clearly allies it with Gerrhopilidae, as this is a common combination of characters in Gerrhopilus, and only found in some individuals of one other African typhlopid species ( Letheobia debilis; Table 2). Thus, we transfer Cathetorhinus to Gerrhopilidae (Table 1).