486 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
18b. Scales in 21-25 longitudinal rows at midbody; an azygous prefrontal scale usually present 
(Fig. 17B).19 
19a. Rostral not divided; upper lip yellow; ventrals 213-245. Laticauda colubrina (Fig. 18B) 
19b. Rostral divided horizontally; upper lip brown; ventrals 195-205; 30-42 bands on body. .. . . 
. Laticauda semifasciata 
20a. More than 72 scale rows around midbody. Hydrophis [Kolpophis] annandalei 
20b. Fewer than 72 scale rows around midbody.21 
21a. Rostral scale fragmented into 4 or 5 smaller scales; dorsal head scales with thickened edges 
. Hydrophis [Thalassophis] anomalus 
21b. Not as above.22 
22a. Three supralabials only, second very elongate. Emydocephalus annulatus 
22b. Not as above.23 
23a. Ventrals much broader anteriorly than posteriorly. Hydrophis [Praescutata] viperina 
23b. Ventrals uniformily small.24 
24a. Venti*al scales small but distinct thi*oughout, undivided by a median groove (Fig. 19B) or, if 
divided posteriorly (Fig. 19C), the two halves either apposed or alternating with one another, 
head very small and front half of body long and veiy slender.25 
24b. Ventral scales, if distinct, then either divided by a median groove (Fig. 19C) or smaller than 
adjacent body scales (Fig. 19A).38 
25a. Not more than 23 scales aboud the thickest part of body. Hydrophis [Kerilia]jerdoni 
25b. At least 25 or more scales around thickest part of body.26 
26a. Head scales regular, usually entire (Fig. 20A); nasal scales in contact with one another; pre¬ 
ocular present.27 
26b. Head scales, especially frontal and parietal, more or less fragmented (Fig. 20B). 
. Hydrophis [Acalyptophis] peronii 
27a. Mental scale normal (Fig. 21 A), not hidden in symphysis grove; ventrals uniform in size; 
1-18 maxillaiy teeth behind fangs.28 
27b. Mental scale elongate, partially hidden in groove in symphysis (Fig. 2IB); ventrals uniform 
in size; 3-5 maxillary teeth behind fangs. Hydrophis [Enhydrina] schistosus (Fig. 22) 
28a. Scales on thickest part of body hexagonal or quadi'angular in shape, weakly imbricate or jux¬ 
taposed (Fig. 23A); 8-18 maxillary teeth behind fangs.29 
28b. Scales on thickest part of body with rounded or bluntly pointed tips, distinctly or weakly 
imbricate (Fig. 23B); 1-8 maxillary teeth behind fangs.32 
29a. Head very small, body long and very slender anteriorly (Fig. 24A); 5-6 maxillary teeth behind 
front fangs.30 
29b. Head not distinctly reduced, body not particularly slender anteriorly (Fig. 24B); head and 
body grayish above, white below; ventrals 195-281; 8-18 maxillary teeth behind fangs.... 31 
30a. Head black with yellowish spots; body grayish above, white below; scales in 25-30 longitu¬ 
dinal rows around neck, 39-49 around thickest part of body; ventrals 323^52. 
. Hydrophis atriceps 
30b. Head blackish with a curved yellow mark across snout and extending backwards along sides 
of head and sometimes a connecting yellow band or two across frontal and parietal region, 
body greyish above, yellowish while below, with 60-80 dark grey bands, usually encircling 
body anteriorly; markings often lost in older adults; 37-45 scales around midbody; ventrals 
328-414. Hydrophis brookii 
