Hydrophis alcocki Wall, 1906

synonym of Hydrophis fasciatus (Schneider, 1799)

(Table 1; Fig. 7)

Material Examined. ZSI 8244 Holotype, from Puri, Odisha (Eastern India).

Description. Head small, head shields large, regular; Rostral broader than high; Nasal superior in position, nasal shield in contact with each other; Prefrontal short, 2 nd supralabial not touching prefrontal; Frontal longer than the distance from the tip of the rostral; Parietal longer than wide; One large anterior temporal; One supraocular on each side of head; One Pre and Postocular on each side of head; Six supralabials on each side of head; 2 nd not touching prefrontal; 3 rd and 4 th touching the eye; Seven infralabials on right side and eight on left side of head; 4 infralabials touching the chin shield; Chinshield well developed; both the pair in contact with each other; Anterior Pair 1.5 mm, Posterior Pair 2.0 mm; Scales around neck 25; Scales around Midbody 28; Ventrals 274, small, distinct from adjacent dorsal scales; Preanal small; No keel present on dorsal scales. Head width 5.8 mm; Head depth 4.6 mm; Head length 13.0 mm; Snout to Vent length 365.0 mm; Tail length 40.0 mm. Dorsally and ventrally the entire body light brown. Body encircled with dark brown bands. Number of bands around the body till vent 40; Four bands on tail.

Remarks. Wall (1906) in his original description did not give scale counts for the type specimen. Smith (1926) stated it to be a male with scale rows 25:33 and ventrals 362. Wall (1909) synonymized H. alcocki Wall, 1906 under H. spiralis, but Smith (1926, 1943) treated it as a synonym of H. atriceps, where it now rests (Wallach et al. 2014; Ganesh et al. 2019). Smith (1926) mixed up the registration numbers of the types of H. alcocki and H. melanocinctus, probably because both these specimens are from Puri, Odisha, India. Thus, the type of H. alcocki is in fact ZSI 8244 and the specimen ZSI 14470 is the type of H. melanocinctus (Das et al. 1998; this work). The nominal taxon H. alcocki has been varyingly treated as a synonym of H. fasciatus and H. atriceps. The validity of H. atriceps as a species distinct from H. fasciatus itself is unsettled and dubious at best (Wallach et al. 2014). This taxon has also been recognized as a subspecies of H. fasciatus (see Rasmussen et al. 2014). Boundy (2020) despite recognizing H. atriceps as a valid species, did not list H. alcocki as its synonym. Therefore, we follow Wall (1909) in treating H. alcocki as a synonym of H. fasciatus. We concur with Das et al. (1998) in that H. alcocki is a synonym of H. fasciatus and not H. atriceps Günther, 1864, an East Asian species (Wallach et al. 2014), absent in India (Whitaker & Captain 2004; Ganesh et al. 2019). Incidentally, Das et al. (1998) had mixed up the taxon authorship of H. fasciatus with that of H. atriceps while clarifying the above point.