A new species of Gracixalus (Anura, Rhacophoridae) from northwestern Vietnam

Abstract

A new species of small tree frog is described from northwestern Vietnam based on morphological dif-ferences and molecular divergence. Gracixalus truongi sp. nov. is distinguishable from its congeners and other small rhacophorid species on the basis of a combination of the following characters: size relatively small, SVL 32.2–33.1 mm in males, 37.6–39.3 mm in females; head slightly wider than long; vomerine teeth absent; snout round and long RL/SVL 0.17–0.19 in males, 0.16–0.17 in females; spines on up-per eyelid absent; supratympanic fold distinct; tympanum distinct; dorsal skin smooth; throat smooth and venter granular; tibiotarsal projection absent; webbing of fingers rudimentary, toes with moderately developed webbing; dorsum moss-green, with an inverse Y-shaped dark green marking extended from interorbital region to posterior region of dorsum; external vocal sac absent in males; males with a nuptial pad on finger I. In the molecular analyses, the new species has no clear sister taxon and is at least 4.5% divergent from other congeners based on a fragment of the mitochondrial 16S rRNA gene.