488 
THE CORAL TRIANGLE: HEARST BIODIVERSITY EXPEDITION 
31b. 39-45 dark middorsal blotches or bands on body; anteriorly interspaces between dorsal dark 
body blotches or bands less than 2 scale rows wide; 8-11 dark bands on tail; 31-39 scale rows 
around neck; ventral seales 224-294; 9-12 maxillary teeth behind front fangs. 
. Hydrophis ornatus 
32a. Usually one anterior temporal (Fig. 25A); 25-31 scale rows around neek; 6-8 upper labials 
.35 
32b. Usually two anterior temporals (Fig. 25B); 31^3 scale rows around neck.33 
33a. 14—18 maxillary teeth behind front fangs; 31-43 scales around neck, 38-54 around midbody; 
ventrals 253-334. Hydrophis caerulescens 
33b. Less than 14 maxillary teeth behind front fangs (usually 10 or fewer).34 
34a. Head in adult olive or yellowish (in young, head may be blaek or dark olive); black ventral 
stripe often present but less distinet in older adults; dorsal portions of black body annuli per¬ 
sist even in older adults; ventrals 290-390. Hydrophis cyanocinctus (Figs. 26A-B) 
34b. Head in adult black; body black with 50 to 60 narrow whitish bands or annuli; ventrals usu¬ 
ally black; ventrals 314-356 (restricted to Lake Taal [Bombon], Luzon). . . Hydrophis semperi 
35a. Usually 5 upper labials, rarely 6; 22-27 scale rows around neck; ventrals 360^15; one ante¬ 
rior temporal. Hydrophis klossi 
35b. Usually 6 or 7 upper labials, rarely 5; 23-31 scale rows around neck, usually greater than 24; 
one anterior temporal, sometimes divided into two superimposed seales.36 
36a. Longitudinal rows of seales increases by 4—8 rows from neck to midbody (25-29[neck]/ 
33-38[midbody] + 4—8 increase in rows) i. Hydrophis spiralis (Figs. 26C-D) 
36b. Longitudinal rows of scales increases by 8-18 rows from neck to midbody; body greatly com¬ 
pressed posteriorly.37 
37a. Head blaek with yellow markings; head small, body long and slender anteriorly, compressed 
posteriorly; 40-55 dark bands on body; 23-27 scale rows around neek, 33^1 around mid¬ 
body; 6-8 maxillary teeth behind front fangs. Hydrophis melanocephalus 
37b. Head black in young with or without a yellow eurved mark above, greyish, olive, or yellow¬ 
ish in adult; head moderate, body elongate, eompressed posteriorly; 25-31 seale rows around 
neck, 37-45 around midbody; 60-80 dark bands on body, fading in adults; 4—5 maxillary teeth 
behind front fangs. Hydrophis belcheri 
38a. Midbody scales in 25^3 rows around body; dorsal scales hexagonal, juxtaposed.39 
38b. Midbody scales in 47-67 rows around body; dorsal scales juxtaposed, or imbricate.40 
39a. Head small, anteriorly body elongate and narrow; scale rows around neek 17-23; seales 
Figures 23A-B. Scales on thickest part of body: (A) hexagonal or quadrangular in shape {Hydrophis atriceps); 
(B) scales rounded or with bluntly pointed tips {Hydrophis cyanocinctus). 
1 After Smith (1926): “represents the number of scale rows on the neck and body, and the increase in the number of 
scale rows from neck to midbody.” 
