LEVITON, BROWN, & SILER: PHILIPPINE VENOMOUS SNAKES 
485 
Seasnakes 
(N.B. Several speeies ineluded in this seed on of the keys have yet to be reported from Philippine waters but have been 
found in neighboring areas, off the eoast of northern Borneo and/or elsewhere in the South China Sea region [indieated by 
boldfaee type]). Also, reeent phylogenetie studies of the sea snake genus Hydrophis and allied genera, have resulted in major 
ehanges in the the generie assignment of speeies. Those ehanges are indieated here by enelosing formerly reeognized gen¬ 
era in braekets [ ] following the now eurrent name for the speeies, e.g., Hydrophis curtus, formerly Lapemis curtus, is shown 
below as Hydrophis [Lapemis] curtus. 
16a. Ventral scales large, one-third to more than one-half the width of the body (Fig. 16A); nostrils 
lateral or superior, nasal scales in contact or separated separated by internasals.17 
16b. Ventral scales small, less than one-fourth width of body, often smaller than or at least not larg¬ 
er than adjacent body scales (Fig. 16B); nostrils variable, intemasal scales absent, nasal scales 
in contact with one another.20 
Figures 16A-B. Ventral scales in sea snakes: (A) large ventral scales in Laticauda (Laticauda colubrina); 
(B) small ventral scales in Hydrophis {Hydrophis atriceps) and other sea snakes. 
17a. Nostrils lateral; nasals separated by intemasals.18 
17b. Nostrils superior; nasals in contact with one another.. Aipysurus eydouxii 
18a. Scales in 19 longitudinal rows at midbody; no azygous prefrontal scale (Fig. 17A); ventrals 
225-243. Laticauda laticaudata (Fig. 18A) 
no azygous prefrontal scale 
azygous prefrontal scale present 
Figures 17A-B. Azygous prefrontal scale: (A) absent in Laticauda laticaudata', (B) present in Laticauda colubrina. 
