Homalopsidae, Bonaparte, 1845

Weinell, Jeffrey L., Hooper, Errol, Leviton, Alan E. & Brown, Rafe M., 2019, Illustrated Key to the Snakes of the Philippines, Proceedings of the California Academy of Sciences 66 (1), pp. 1-49 : 14

Homalopsidae

Key to Philippine genera.

1a. Supralabial scales do not border eye; frontal scale fragmented into multiple smaller scales; internasal scales paired, positioned posterior to a pair of nasal scales; nasal scales in contact with each other medially ( Fig. 9A )....................................... Cerberus (p. 21)

1b. One or more supralabial scales usually border eye; frontal scale not fragmented; internasal scale single, not paired, and is positioned medially between a pair of nasal scales; nasal scales not in contact with each other medially..................................... Gerarda (p. 24)

Figures

FIGURE 9. Dorsal view of head of (A) Cerberus schneideri (KU 305489), (B) Opisthotropis typica (KU 327424), (C) Calamaria gervaisii (KU 322329), (D) Liopeltis philippinus (KU 327731). Frontal scale (reddish brown), prefrontal scales (blue), internasal scales (purplish-gray), nasal scales (green).