LEVITON, BROWN, & SILER: PHILIPPINE VENOMOUS SNAKES 
481 
la. Pupil of eye round; loreal scale absent (Fig. 4); venom fangs short, permanently erect; maxil¬ 
lary bone elongate, usually with several small teeth behind front fangs (Family Elapidae, 
including cobras, coral snakes, and sea snakes) (see Fig. 31).2 
lb. Pupil of eye vertically elliptical (Fig. 5A); loreal scale absent; upper surface of head either cov¬ 
ered by small scales (Fig. 5B) or large, symmetrical scales; a deep sensory pit present imme¬ 
diately behind the nostril (Fig. 5A); venom fangs variable in length, fixed to a short moveable 
maxillary bone that allows for rotation of the fangs backward when the mouth is closed; no 
teeth behind fangs (Family Viperidae) (see Fig. 3J).12 
2a. Tail flattened laterally, oar-like (Fig. 6A) (sea snakes).16 
2b. Tail rounded, tapering (Fig. 6B) (terrestrial snakes).3 
3a. Scales in 13-15 longitudinal rows at midbody; scales on sides of body variable, in either 
oblique or parallel rows (Figs. 3D, 3E, 8A, and 8B).4 
3b. Scales in 17-25 longitudinal rows at midbody; scales on sides of body in oblique rows [Fig. 
3D, also Fig. 8A for Ophiophagus] (Genus Naja) .10 
4a. Scales on sides of body in oblique rows (Figs. 3D, 8 A); number of scales on posterior third of 
body at least two less than on anterior third (Balabac, Jolo, Luzon, Mindanao, Mindoro, 
Negros, Panay, Palawan, Polillo). Ophiophagus hannah (Fig. 7A) 
4b. Scales on sides of body in parallel rows (Figs. 3E, 8B); number of scales on posterior third of 
body equal to number on anterior third.5 
5a. Scales in 15 longitudinal rows at midhody (Genus Hemibungarus) .6 
5b. Scales in 13 longitudinal rows at midbody (Genus Calliophis) .8 
6a. Black rings on dorsum of body not divided by narrow white annuli; temporal region heavily 
pigmented with melanin; white annuli on dorsum usually less than 60.7 
round eye pupil 
preocular 
nasals 
Figure 4. Pupil of eye oiNaja philippinensis; loreal seale absent. 
elliptic eye pupil 
Figures 5A-B. Tropidolaemus subannulatus: (A) Lateral view of head (B) Dorsal view of head. 
Figures 6A-B. Tails of sea snakes (A. laterally eompressed, paddle-shaped) and 
terrestrial snakes (B. not eompressed, rounded and tapering toward tip). 
