Monday, March 13, 2023

[Herpetology • 2023] Gracixalus truongi • A New Species of Gracixalus (Anura: Rhacophoridae) from northwestern Vietnam

Gracixalus truongi 
Tran, Pham, Le, Nguyen, Ziegler & Pham, 2023

Truong’s Treefrog | Nhái cây trường  ||  DOI: 10.3897/zookeys.1153.93566

A new species of small tree frog is described from northwestern Vietnam based on morphological differences and molecular divergence. Gracixalus truongi sp. nov. is distinguishable from its congeners and other small rhacophorid species on the basis of a combination of the following characters: size relatively small, SVL 32.2–33.1 mm in males, 37.6–39.3 mm in females; head slightly wider than long; vomerine teeth absent; snout round and long RL/SVL 0.17–0.19 in males, 0.16–0.17 in females; spines on upper eyelid absent; supratympanic fold distinct; tympanum distinct; dorsal skin smooth; throat smooth and venter granular; tibiotarsal projection absent; webbing of fingers rudimentary, toes with moderately developed webbing; dorsum moss-green, with an inverse Y-shaped dark green marking extended from interorbital region to posterior region of dorsum; external vocal sac absent in males; males with a nuptial pad on finger I. In the molecular analyses, the new species has no clear sister taxon and is at least 4.5% divergent from other congeners based on a fragment of the mitochondrial 16S rRNA gene.

Keywords: 16S rRNA, Dien Bien Province, Gracixalus truongi sp. nov., morphology, Rag1, Son La Province, taxonomy

Gracixalus truongi sp. nov., holotype (IEBR A.5004), male, in life
A dorsolateral view B ventral view.

Gracixalus truongi sp. nov., dorsolateral view of paratypes in life
A female (IEBR A.5005) from Dien Bien Province B female (ZVNU 09) from Son La Province.

 Gracixalus truongi sp. nov.
Diagnosis: The new species is assigned to the genus Gracixalus based on molecular phylogenetic analyses and the following morphological characters: the presence of intercalary cartilage between terminal and penultimate phalanges of digits, tips of digits expanded into large discs bearing circum-marginal grooves, the vomerine teeth being absent, horizontal pupil, tibia ~ 4–5× longer than wide, translucent skin, inner (first and second) and outer (third and fourth) fingers not opposable, and dorsum with an inversed Y-shaped dark brown marking (Fei et al. 2009; Rowley et al. 2011, 2020; Chen et al. 2018; Yu et al. 2019; Le et al. 2021).

Etymology: We name this new species in honor of our colleague, Prof. Dr. Truong Quang Nguyen from the Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, in recognition of his great contributions to the herpetofaunal exploration of the Indochina region. 
We recommend “Truong’s Treefrog” as the common English name of the new species 
and the common name in Vietnamese “Nhái cây trường”.

Tung Thanh Tran, Anh Van Pham, Minh Duc Le, Nam Hai Nguyen, Thomas Ziegler and Cuong The Pham. 2023. A New Species of Gracixalus (Anura, Rhacophoridae) from northwestern Vietnam.  ZooKeys. 1153: 15-35. DOI: 10.3897/zookeys.1153.93566