Wednesday, May 4, 2022

[Herpetology • 2022] Theloderma hekouense • A New Cryptic Species in the Theloderma rhododiscus complex (Anura, Rhacophoridae) from China–Vietnam Border Regions


 Theloderma hekouense 
 Du, Wang, Liu & Yu, 2022

Hekou Bug-eyed Frog | 河口棱皮树蛙  ||  DOI: 10.3897/zookeys.1099.80390

Abstract
We describe a new species of Theloderma from southern Yunnan, China and northern Vietnam based on morphological and molecular evidence. Theloderma hekouense sp. nov., which had been recorded as T. rhododiscus, is the sister to T. rhododiscus. The new species differs genetically from T. rhododiscus by 4.2% and 10.7% in 16S rRNA and COI genes, respectively, and it can be morphologically distinguished from T. rhododiscus by having more densely spaced white warts on the dorsal surface, red subarticular tubercles, red metacarpal tubercles, a red metatarsal tubercle, and black dorsal and ventral surfaces in preservative. Currently the new species is only known from the China–Vietnam border regions of Yunnan and Ha Giang, while T. rhododiscus has a wide distributional range in China including Guangxi, Guangdong, Hunan, Fujian, Jiangxi, and presumably Guizhou and eastern Yunnan. Including the new species, there are currently 10 Theloderma species in China and seven Theloderma species in Yunnan, where more species will probably be found.

Keywords: 16S rRNA, COI, southern Yunnan, Theloderma hekouense sp. nov.

Views of holotype of Theloderma hekouense sp. nov. (GXNU YU000496) in life.

Theloderma hekouense sp. nov. and T. rhododiscus
A–C dorsal and ventral views of Theloderma hekouense sp. nov. A, B holotype (GXNU YU000496) in preservative C paratype (GXNU YU000495) in life
D–F T. rhododiscus D, E topotype (GXNU YU000069) in preservative F topotype (GXNU YU000417) in life.

 Theloderma hekouense sp. nov.

Diagnosis: The new species was assigned to genus Theloderma by its phylogenetic position and the following morphological characters: distinct tympanum, terminal phalanx with Y-shaped distal end, intercalary cartilage between terminal and penultimate phalanges of digits, tips of digits expanded into large discs bearing circummarginal grooves, head skin not co-ossified to skull (Poyarkov et al. 2018). Theloderma hekouense sp. nov. can be distinguished from T. rhododiscus and other congeners by having a combination of the following characters: 1) small body size; 2) dorsal surface coarsely rough with large ridges and tubercles; 3) dense warts on dorsal surface; 4) absence of white markings on dorsal surface; 5) iris uniformly reddish brown; 6) discs, metacarpal tubercles, metatarsal tubercles, and subarticular tubercles red; 7) webbing between fingers, vocal sac, and vomerine teeth absent.

Habitat of Theloderma hekouense sp. nov.
 A habitat at the type locality B an individual found in a water bucket that was set up in the field as potential breeding site of treefrog preferred breeding in water-filled tree holes by the authors for amphibian monitoring.


Etymology: The specific epithet is named after the type locality, Hekou County, Yunnan, China. We suggested “Hekou Bug-eyed frog” for the common English name and 河口棱皮树蛙 (Hé Kǒu Léng Pí Shù Wā) for the common Chinese name.

 

  Lingyun Du, Jian Wang, Shuo Liu and Guohua Yu. 2022. A New Cryptic Species in the Theloderma rhododiscus complex (Anura, Rhacophoridae) from China–Vietnam Border Regions.  ZooKeys. 1099: 123-138. DOI: 10.3897/zookeys.1099.80390