Description of two new species of Microhyla (Anura: Microhylidae)from Bangladesh.

Abstract

Two new frog species belonging to genus Microhyla from the southeast, central and northeast regions of Bangladesh are described. Based on a molecular phylogeny derived from mitochondrial DNA sequences, one of the new species forms a clade with M. fissipes, while the second new species is sister to this clade. The DNA sequences of the mitochondrial cytochrome b gene from these new species are substantially diverged from M. fissipes (8.9 and 10.2% [3.6 and 4.2% for 16S ribosomal RNA gene] uncorrected pairwise divergence, respectively), and the estimated phylogenetic splits from their closest relative is in the Pliocene (3.4 Mya) and middle Miocene (10.5 Mya). The first new species (Microhyla mukhlesuri sp. nov.) can be diagnosed from its nearest congener (M. fissipes) by the following characteristics: SVL: 16.5-21.0 mm, finger length 1 < 4 < 2 < 3, tips of finger and toes not swollen, subarticular tubercles distinct, an inverse U-shaped mark on the anus, and a distinct X-shaped marking on the dorsum. Although the second new species (M. mymensinghensis sp. nov.) shares some morphological characteristics with the first new species, it can be readily diagnosed from its close congeners by its longer hindlimbs (HLL/SVL), tibia (TIL/SVL) and forearm width (FAW/SVL), in addition to a combination of the following characteristics: SVL: 14.2-21.3 mm, snout truncate, a crescent-shaped marking on the anus, and an X-shaped marking on the dorsum. The tibio-tarsal articulation extends to the eye in M. fissipes but ranges from the eye to the tip of the snout in the two new species.