A new species of Gracixalus (Anura: Rhacophoridae) with a hyperextended vocal repertoire from Vietnam

摘要

We describe a new species of small rhacophorid frog from north central Vietnam. Gracixalus quangi sp. nov. is morphologically and genetically most similar to G. gracilipes and G. supercornutus, but is distinguished from these species and all other rhacophorids in Vietnam and adjoining countries by a combination of their small size (males <25 mm); greenish, translucent skin; opaque yellow anterior surface of thighs, groin, and behind the insertion of the arm; black spots on the flanks and ventral surface of the thighs; triangularly pointed snout; and the presence of a tibiotarsal projection. Gracixalus quangi sp. nov. has a non-stereotypical, hyperextended vocal repertoire, with calls highly variable in structure, duration, amplitude and frequency (dominant frequency 4.1-4.7 kHz). Like G. gracilipes and G. supercornutus, G. quangi sp. nov. deposits egg clutches in clumps on leaves overhanging shallow forest pools or puddles. The new species is known from montane evergreen forest in Pu Hoat ProposedNature Reserve in western Nghe An Province, between -600-1,300 m elevation. Preliminary molecular (mtDNA) data recovered two strongly supported clades within frogs currently considered to belong to genus Gracixalus, with the new species nested within a monophyletic clade consisting of G. gracilipes, G. supercornutus, and G. quyeti.