Integrative taxonomic evidence for a new species of the short-legged toads Brachytarsophrys (Anura, Megophryidae) from Guangxi, China

Currently, the genus Brachytarsophrys contains nine species. In this study, we describe a new species of Brachytarsophrys, named Brachytarsophrys guilinensis sp. nov., from northeastern Guangxi, China, based on morphological, molecular, and acoustic evidence. This new species can be distinguished from other known congeners by the combination of the following morphological characters: (1) smaller body size (SVL 70.0‒ 81.9 mm in eight adult males); (2) head wider than long, with head width nearly 1.5 times the length and about half of the SVL; (3) tongue broad and round, feebly notched; (4) male with nuptial pad on the dorsal surface of the first and second fingers; (5) hind limbs relatively short and robust, heels not meeting when legs are positioned at a right angle to the body; (6) tibiotarsal articulation reaching the angle of the mouth when hind limbs are extended forward alongside the body; (7) absence of outer metatarsal tubercle, with the inner metatarsal tubercle oval and approximately equal to the first toe; (8) fingers without webbing; toes with incomplete webbing, webbing formula: I 1 - 2 II 1 - 2 III 1 ½ - 3 - IV 3 - - 1 ½ V; (9) lateral fringes on toes wide; (10) several warts on the outer side of the upper eyelid, with one being relatively larger.

Phylogenetic analyses based on mitochondrial 16 S rRNA, COI, and Cytb genes revealed that this new species is more closely related to B. popei and B. orientalis than to other known species, with strong Bayesian posterior probability and moderate bootstrap support. More studies are necessary to clarify the taxonomy and species diversity of the genus Brachytarsophrys in Guangxi, China.