Hydrophis viperinus (Schmidt, 1852)

Rezaie-Atagholipour, Mohsen, Ghezellou, Parviz, Hesni, Majid Askari, Dakhteh, Seyyed Mohammad Hashem, Ahmadian, Hooman & Vidal, Nicolas, 2016, Sea snakes (Elapidae, Hydrophiinae) in their westernmost extent: an updated and illustrated checklist and key to the species in the Persian Gulf and Gulf of Oman, ZooKeys 622, pp. 129-164 : 137-138

Taxon classification Animalia Squamata Elapidae

Hydrophis viperinus (Schmidt, 1852) Figures 3b, 4a, 8, 9

Thalassophis viperina Schmidt, 1852: 79.

Thalassophis viperina - Smith 1926: 35. - Volsøe 1939: 10.

Hydrophis jayakari - Boulenger 1887: 408.

Hydrophis plumbea - Murray 1887: 34.

Distira viperina - Boulenger 1896: 298.

Praescutata viperina - Corkill and Cochrane 1965: 494. - Joger 1984: 31. - Leviton and Aldrich 1984: XXIV. - Gasperetti 1988: 325. - Leviton et al. 1992: 127. - Carpenter et al. 1997: 249. Firouz 1999: 192. - Baldwin and Gardner 2005: 251. - Firouz 2005: 210. - Egan 2007: 166. - Rastegar-Pouyani et al. 2008: 20. - Soorae et al. 2010: 535.

Hydrophis viperinus - Kamali 2013: 244. - Safaei-Mahroo et al. 2015: 282.

Material examined.

Gulf of Oman: 2 specimens, Beris and Pasa-Bandar, depth 20-40m [(ZMSBUK.HD.20), TL 737, SVL 656, HL 19.1, HW 12.6, GL 14.8, SNL 3, NEL 3, ND 35, GBD 67, NSL 8, NSR 29, BSR 47, NV 250; (ZMSBUK.HD.43), TL 740, SVL 657, HL 18.9, HW 14.9, GL 13.3, SNL 3.9, NEL 2.8, ND 38, GBD 68, NSL 7, NSR 30, BSR 43, NV 265], August 2013, collector: M. Rezaie-Atagholipour.

Diagnosis.

Head large, short and depressed (Figures 8-9); tip of rostral curved and markedly tridentate (Figures 2b, 3b); usually 7-8 supralabials, none in contact with prefrontal (Figure 8); 250-265 large ventrals [245-291 ( Volsøe 1939)], markedly distinguishable from adjacent scales (Figure 4a), larger anteriorly than posteriorly; ventrals on anterior part of body wide and enlarged, half width of body, more or less rectangular in shape; 29-38 scale rows on neck, 39-47 on body [27-31 and 40-43 ( Volsøe 1939)].

Coloration.

Dark gray dorsally, dirty white ventrally; with or without pale body bands broadest dorsally; tip of tail usually black (Figure 9d).

Size.

Maximum TL 740 mm (n = 2); [n = 8, mean TL 662 mm, maximum TL 780 mm ( Volsøe 1939)].

General distribution.

Indian Ocean, from the Persian Gulf to Malay Archipelago ( David and Ineich 1999).

IUCN Red List Category.

Least concern ( IUCN 2016).

Remarks.

Hydrophis viperinus is distinct from other sea snakes in the Persian Gulf and Gulf of Oman by having markedly rectangular-shaped and enlarged ventrals on the anterior part of the body. Smith (1926) and Wall (1921) mentioned that the Persian Gulf is the westernmost distribution limit of Hydrophis viperinus . Volsøe (1939) had doubts about it: "their only exact records from the Persian Gulf are however from Muscat, which is situated about 400 km outside the Strait of Hormoz". We agree with Volsøe (1939) as the two specimens we examined in this study and the specimens examined in other studies in the area (e.g. Boulenger 1887; Volsøe 1939) have all been collected from the Gulf of Oman. We did not find any specimen of Hydrophis viperinus in Iranian coastal waters of the Persian Gulf during our field surveys. Therefore, population of Hydrophis viperinus in the Persian Gulf, if present, seems likely to be in low abundance.