Abstract
We describe a new species of small megophryid frog from the Langbian Plateau in southern Vietnam, the southernmost record of Leptolalax from Vietnam. Leptolalax bidoupensis sp. nov. is distinguished from its congeners by a combination of a dark brownish red ventral surface with white speckling on entire ventral surface including throat, arms and legs, small size (23.6-24.6 mm in four adult males and 29.2-29.4 mm in two adult females), bicoloured iris (coppery red upper half, fading to pale silver ventrally), a mostly smooth skin texture with no skin ridges, and relatively short tibia (male TIB:SVL 0.44-0.46). The male advertisement call of the new species, consisting of 6-9 single-pulsed notes with a dominant frequency of 1.9-3.8 kHz, is also uniqueamong Leptolalax species for which calls are known. From the morphologically similar L. applebyi and L. melicus, L. bidoupensis sp. nov. differs by 9.3% and 9.6% sequence divergence at the 16S mtD-NA gene. At present, the new species is known from montane evergreen forest between 1620-1730 m elevation, within an area of 1 km~2. We suggest the species should be considered Data Deficient following IUCN's Red List categories.
NSTL