Illustrated Key to the Snakes of the Philippines Author Weinell, Jeffrey L. Department of Ecology and Evolutionary Biology and Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045; jweine2@gmail.com Author Hooper, Errol Department of Ecology and Evolutionary Biology and Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045; Author Leviton, Alan E. Herpetology Division, Institute of Biodiversity Science & Sustainability, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, California 94118. * Corresponding author; Email: jweine 2 @ gmail. com Author Brown, Rafe M. Department of Ecology and Evolutionary Biology and Biodiversity Institute, University of Kansas, Lawrence, Kansas 66045; text Proceedings of the California Academy of Sciences 2019 2019-09-30 66 1 1 49 journal article 299708 10.5281/zenodo.11512680 ccd739a4-10c3-4700-b27e-459bd82f1676 0068-547X 11512680 Pseudorabdion Key to Philippine species. 1a. Loreal scale absent, prefrontal scale in contact with supralabial scales ( Fig. 43B–D )....... 2 1b. Loreal scale present, prefrontal scale not in contact with supralabial scales ( Fig. 43A )..... 4 2b. Frontal scale does not border eye; supraocular and postocular scales present, fused to each other ( Fig. 43C–D )................................................................ 3 2a. Frontal scale borders eye; supraocular scale absent ( Fig. 43B )........................ 6 3a. Parietal scale in contact with fourth and fifth supralabial scales ( Fig. 43C ); each scale of first dorsal body scale row has dark center and light edges; each ventral body scale dark brown, lighter along posterior edge; supraocular and postocular scales usually fused to eye; ventral body scales 132–144 (males), 144–157 (females); subcaudal scales 22–24 (males), 16–17 (females).................................................... Pseudorabdion oxycephalum 3b. Parietal scale in contact with fifth, but not fourth, supralabial scale ( Fig. 43D ); each scale of first dorsal body scale row has light center and dark edges; each ventral body scale whitish, with dark brown pigment confined to a broad transverse band; supraocular and postocular scales not fused to eye; ventral body scales 146–148 (males), 154–161 (females); subcaudal scales 28 (males), 21–24 (females).................................. Pseudorabdion montanum 4a. Light nuchal collar usually present; subcaudal scales 26–29 (males), 17–23 (females)............................................................ Pseudorabdion mcnamarae 4b. Light nuchal collar absent; subcaudal scales> 30 (males and females).................. 5 FIGURE 43. Lateral view of head of (A) Pseudorabdion mcnamarae (KU 327199), (B) Pseudorabdion cf. collaris (KU 315197), (C) Pseudorabdion oxycephalum (KU 324641), (D) Pseudorabdion montanum (KU 305063). Loreal scale (green; A), parietal scale (purplish-gray; C–D), fourth supralabial scale (light gray; C–D), postocular scale (blue; B), frontal scale (reddish brown; B–D), scale formed from fusion of supraocular and postocular scales (yellow; C–D). 5a. Dorsal body scales uniform pale brown, each thinly edged with pigmentless border; distal portion of hemipenes calyculate, subcaudal scales 33–35 (females), 40 (males)...................................................................... Pseudorabdion taylori 5b. Dorsal body scales pale, centers and posterior tips nearly without pigment; anterior edge of each dorsal body scale with brown mottling; large areas of lateral portion of ventral body scales without pigment; distal portion of hemipenes minutely spinose; subcaudal scales 36–39 (males; unknown for females)..................................... Pseudorabdion talonuran 6a. Postocular scale absent (fused to ocular scale); maxillary teeth 10–12... Pseudorabdion ater 6b. Postocular scale present, not fused to ocular scale ( Fig. 43B ); maxillary teeth 22–25............................................................. Pseudorabdion cf. collaris