3. Overall body colour grey or greyish-brown; dorsal pattern reticulated with a broad vertebral stripe ...........
.....................................................................................................................................Oligodon formosanus
- Overall body colour shades of ochre or brown; dorsal pattern usually blotched; vertebral stripe reduced to
a narrow line or absent..................................................................................................................................4
4. Hemipenes long, thin, strongly forked and calyculate; unknown south of central Thailand; pattern made
either of dorsal blotches broad and long (3 dorsal scales long) or strongly reticulate with fasciatures .......5
- Hemipenes long, single, with large papilla; unknown north of southern peninsular Thailand; dorsal
blotches narrow (1 or 2 dorsal scales long) ..............................................................Oligodon purpurascens
5. Dorsal scale row reduction from 17 to 15 posterior to VEN 115; dorsal blotches, when present, rather narrow
and dark brown or black; northeastern India, Myanmar, Yunnan, and extreme western Thailand.........
..........................................................................................................................................Oligodon cyclurus
- Dorsal scale row reduction from 17 to 15 DSR at most at VEN 115; dorsal blotches, when present, rather
long and broad, with a lighter centre; southern Vietnam, southern Laos and Cambodia ...............................
......................................................................................................................................... Oligodon ocellatus
6. 17 DSR at neck; hemipenes extend to SC 13 ..................................................................Oligodon chinensis
- 19 DSR at neck; hemipenes extend to SC 28 ............................................ Oligodon saintgironsi spec. nov.