Isanophis, David, Patrick, Pauwels, Olivier S. G., Nguyen, Truong Quang & Vogel, Gernot, 2015

David, Patrick, Pauwels, Olivier S. G., Nguyen, Truong Quang & Vogel, Gernot, 2015, On the taxonomic status of the Thai endemic freshwater snake Parahelicops boonsongi, with the erection of a new genus (Squamata: Natricidae), Zootaxa 3948 (2), pp. 203-217 : 205-206

Isanophis gen. nov.

( Fig. 1 A–D)

Type species. Parahelicops boonsongi Taylor & Elbel, 1958 by present designation.

Diagnosis. A genus of snake of the family Natricidae characterized by (1) posterior maxillary teeth strongly enlarged, (2) nostrils dorsolateral and directed obliquely upwards; (3) eye diameter slightly greater than the eyenostril distance and distinctly greater than the distance between its lower margin and the margin of the lip, (4) pupil round, (5) dorsal scales strongly keeled with a thick median keel throughout the body, (6) body stout, (7) head strongly distinct from neck, and (8) prefrontal scale single.

Etymology. The generic nomen Isanophis is derived from the word “Isan”, the Thai name of the north-eastern region of Thailand, and from the Greek word ophis, meaning “snake”. It describes the limited known range of this genus. This generic nomen is masculine in gender.

We suggest the following common generic names in English / French / German respectively: Isan Keeled Stream Snakes / Isanophides / Isan Gebirgswassernattern.

Contents. This genus contains a single species, Isanophis boonsongi ( Taylor & Elbel, 1958) , currently known only from north-eastern Thailand.

Figures

FIGURE 1. Isanophis boonsongi new comb., preserved holotype (FMNH 135328). From top to bottom: Dorsal view - Ventral view - Lateral view of the head and neck, left side. Photographs by Patrick David.