506 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
ventral stripe; in adults, ventral stripe and 
lower portions of annuli less distinet but 
dorsal portion of annuli remain distinet. 
Size.— Total length (cJ) 1500 mm, 
($) 1885 mm; tail length (3) 130 mm, 
(?) 135 mm. 
Distribution. — Philippines 
(Luzon; Visayan region) {fide Aleala 
1986a: 164). Elsewhere: Extensive range 
from Persian/Arabian Gulf east to 
Indonesia and north to the Idzu Sea, 
Japan (see David and Ineieh [1999:108] 
for details). 
Hydrophis gracilis (Shaw, 1802) 
Common Small-headed Sea Snake 
Figure 19C 
“Kadell nagam” Russel, 1801:pl. 15, pi. 13. 
Hydrus gracilis Shaw, 1802:560 (Type local¬ 
ity: unknown). 
Microcephalophis gracilis. Smith, 1926:121. —David and Ineieh, 1999:110.— Rasmussen et al. 2011:6. 
Description. — Head very small, elongate, snout projecting beyond lower jaw; body long and 
slender anteriorly, compressed posteriorly and four to five times the diameter of neck; 5-6 maxil¬ 
lary teeth behind front poison fangs; rostral scale large, extending well onto upper surface of snout; 
scale rows on neck 17-23, on body 30^3, posterior scales hexagonal, juxtaposed, broader than 
long, with two or three tubercles, one behind the other; ventrals 215-350, entire and broader than 
adjacent body scales on anterior slender portion of body, completely divided posteriorly by a medi¬ 
an groove, the two halves apposed or alternating to one another; precloacal scales slightly enlarged; 
color in young black anteriorly with whitish dorsal bands or oval spots laterally, 40-60 more or less 
complete bands posteriorly, in adults markings lose definition and body becomes more uniformly 
greyish above, and paler below. 
Size.— Total length (c?) 950 mm, (?) 1025mm; tail length (cJ) 80 mm, (?) 95 mm. 
Distribution. — Philippines (this species has not been recorded from the Philippines but it 
has been found in the South China Sea off the coast of Vietnam and southern China). Elsewhere: 
widely distributed from Persian/Arabian Gulf (coastal Saudi Arabia, Kuwait, Iraq, Iran, and Oman) 
east to the Bay of Bengal, Gulf of Thailand, Malaya and Singapore, South China Sea, and Indone¬ 
sia, to New Guinea (Gulf of Guinea). 
Remarks. — Smith (1943:473) provides information on the geographic variation in scale 
counts for this species. 
Figure 39. Hydrophis cyanocinctus Daudin, 1803 (inset: close- 
up view of head). Photos courtesy of Harold Voris 
Hydrophis inornatus (Gray, 1849) 
Remarks. — According to David and Ineieh (1999:111), Rasmussen (1989) referred records 
of Philippine and Indonesian//, inornatus to H. ornatus (see Rasmussen synonymy, 1989:399, also 
comments on p. 410). Rasmussen also states, “However, the acceptance of//, inornatus as a sepa¬ 
rate species is explicitly preliminary and further study may show that the type specimen of 
H. inornatus is an abberant specimen of H. ornatus.'' (Rasmussen 1989:415.) 
