Oligodon wagneri, David, Patrick & Vogel, Gernot, 2012

David, Patrick & Vogel, Gernot, 2012, A new species of the genus Oligodon Fitzinger, 1826 (Squamata: Colubridae) from Pulau Nias, Indonesia, Zootaxa 3201, pp. 58-68 : 66

Key to the species of Oligodon in the Sumatra region

In the region of Sumatra, nine species of Oligodon are now recognized: O. bitorquatus Boie, 1827 , O. octolineatus (Schneider, 1801) , O. petronellae Roux in De Rooij, 1917, O. praefrontalis Werner, 1913 , O. pulcherrimus Werner, 1909 , O. purpurascens (Schlegel, 1837) , O. signatus (Günther, 1864) , O. trilineatus (Duméril, Bibron & Duméril, 1854) , and O. wagneri sp. nov. On the basis of Tillack & Günther (2010) and of our material, these species can be identified with the following key (adapted from David & Vogel 1996 and Tillack & Günther 2010).

1. Anal plate divided..................................................................................... 2

- Anal plate entire...................................................................................... 3

2. 15 DSR at midbody; no internasals, no loreals................................................... O. praefrontalis

- 17 DSR at midbody; internasals present (exceptionally absent); loreals present......................... O. pulcherrimus

3. 19 or 21 DSR at neck and at midbody......................................................... O. purpurascens

- No more than 17 DSR at neck and midbody................................................................. 4

4. Dorsal pattern distinctly striped with 3 to 8 stripes............................................................ 5

- Dorsal pattern blotched or with crossbars, only a blotched vertebral stripe possible.................................. 6

5. Dorsal pattern made of 6, 7 or 8 dark stripes; usually 6 supralabials................................... O. octolineatus

- Dorsal pattern made of 3 narrow dark stripes; 7 supralabials.......................................... O. trilineatus

6. 15 DSR around the neck and at midbody................................................................... 7

- 17 DSR around the neck, most usually 17 (exceptionally 15) DSR at midbody..................................... 9

7. Dorsal pattern made of a series of 20–25 elongate vertebral blotches, connected by a stripe anteriorly, turning to dark-edged rhombic blotches posteriorly.................................................................. O. petronellae

- Dorsal pattern made of widely separated vertebral blotches or crossbars.......................................... 8

8. Anterior vertebral blotches chevron-shaped on the sides of the neck; body not dotted with pale spots; 144–150 ventrals in males....................................................................................... O. signatus

- Anterior vertebral blotches short, not chevron shaped; body heavily dotted with pale spots; 156 ventrals… O. wagneri sp. nov.

9. Pattern made of large, broad vertebral blotches, the 2 or 3 anterior ones chevron-shaped on the sides of the neck; body not dot- ted with pale spots; 44–59 SC; loreal always present.................................................. O. signatus

- Pattern made of a mixture of small vertebral blotches, the anterior ones not chevron-shaped on the sides of the neck, and of numerous narrow crossbars; body heavily dotted with pale spots forming vertical bars; 29–44 SC; loreal present or absent............................................................................................ O. bitorquatus