A new species of Odorrana (Anura, Ranidae) from the limestone karst forest of northern Vietnam

A new species of Odorrana is described from the limestone karst forest in northern Vietnam based on morphological differences and molecular divergence. Morphologically, Odorrana nagao sp. nov. is distinguishable from its congeners by the following combination of characteristics: size medium (SVL 37.4 mm in male, 47.1–54.7 mm in females); head longer than wide; tympanum distinct, round, ~ 50 % of the diameter of eye; vomerine teeth present; males without external vocal sac; nuptial pad present on finger I in males; webbing formula I 0–1 II 0 – 1 III 0 – 11 / 3 IV 11 / 3 – 1 / 4 V; tibio-tarsal articulation reaching the tip of snout when hindlimb adpressed along body; dorsolateral conical spines present; dorsolateral fold present; dorsum moss-green with brown mottling; ventral surface cream with dark brown mottling.

Phylogenetic analyses of mitochondrial 16 S rRNA and COI gene sequences supported the new species as a sister taxon to an unresolved clade consisting of Odorrana calciphila, O. concelata, O. feii, O. liboensis and O. lipuensis (UFB = 98, PP = 1). The uncorrected p-distances of 16 S rRNA and COI genes between the new species and its closest congeners were 2.33 % and 6.33 %, respectively.