A revision of the genus Macrocalamus (Serpentes: Colubridae), with description of a new species and a key to the genus

The Asian snake genus Macrocalamus (Serpentes, Colubridae), endemic to Peninsular Malaysia, is revised based on the examination of 119 preserved specimens in conjunction with observations on living, freshly collected animals. The species M. lateralis was previously reported as having a red or yellow venter, with or without ventrolateral stripes. It is shown that a positive correlation exists between the colour of the venter, the occurrence of the ventrolateral stripes, and morphological and meristic data. Therefore, the yellow-bellied form is considered to be specifically distinct from the red-bellied form. The hemipenes of two species (M, lateralis, M. schulzi, new species) are described for the first time. Macrocalamus tweediei, previously known from only three specimens, is redefined on the basis of nine recently collected animals. A key to the genus and new biological data are provided.