Revision of the Madagascan snake genus Heteroliodon Boettger (Reptilia : Squamata : Colubridae)

Heteroliodon Boettger is one of the many poorly known, endemic, colubrid ge nera of Madagascar. Described in 1913, this monotypic genus was known only from the holotype of the single species until 1994 when we reviewed the gen us and provided data for seven additional specimens. Since then, we obtaine d 15 more specimens of Heteroliodon, most of which are from new localities, and two of which represent a second species of the genus. The new species, Heteroliodon lava, is distinguished from the type species, Heteroliodon oc cipitalis, by its larger size (maximum snout-vent length = 365 mm compared to 265 mm for H. occipitalis), absence of a light-colored vertebral stripe (invariably present in H, occipitalis), and higher number of ventral scales (214-224, versus 158-182). Heteroliodon occipitalis is restricted to the d ry spiny and deciduous forests of southern and southwestern Madagascar. The two known specimens of H. lava were found in the deciduous forest/karst ha bitats of the Behmaraha and Ankarana regions of west-central and northweste rn Madagascar.