A new species of the genus Tylototriton (Urodela, Salamandridae) from western Thailand.

Porrawee Pomchote,Axel Hernandez,Wichase Khonsue,Panupong Thammachoti,Pitak Sapewisut,Kanto Nishikawa,Parada Peerachidacho

doi:10.3897/zookeys.1072.75320

Abstract

We describe a new species of the newt genus Tylototriton from Umphang Wildlife Sanctuary, Tak Province, western Thailand based on molecular and morphological evidence and named here as Tylototritonumphangensissp. nov. The new species is assigned to the subgenus Tylototriton and differs from other species in having dark-brown to blackish-brown body and limbs, truncate snout, prominent antero-medial ends of the expansion of the dentary bones, laterally protruding quadrate regions, indistinct and small rib nodules, a well-segmented vertebral ridge, and rough dorsolateral bony ridges, which are steeper anterior, and curved medially at the posterior ends. The molecular data show that Tylototritonumphangensissp. nov. differs from T.uyenoi sensu stricto by a 5% genetic sequence divergence of the mitochondrial NADH dehydrogenase subunit 2 region gene. The new species and T.uyenoi are both endemic to Thailand, distributed along the Northwest Thai (Dawna) Uplands of Indochina. To clarify the species boundary between Tylototritonumphangensissp. nov. and T.uyenoi, additional field research is needed in adjacent areas. Tylototritonumphangensissp. nov. is restricted to evergreen hill forests in Umphang Wildlife Sanctuary. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List.

Highlights

The mean likelihood score of the Bayesian inference (BI) analyses for all trees sampled at stationary was −4033.667
Molecular and morphological evidence indicate that the newts found at Umphang Wildlife Sanctuary (UPWS), Tak Province, western Thailand are a distinct, new species described here
With our description of this new species, the number of Tylototriton species is 33, with six of them present in Thailand: T. verrucosus, T. uyenoi, T. panhai, T. anguliceps, T. phukhaensis, and T. umphangensis sp. nov. Three of these six species are endemic to Thailand (T. uyenoi, T. phukhaensis, and T. umphangensis sp. nov.)

Summary

Introduction

The salamandrid genus Tylototriton Anderson, 1871, commonly known as crocodile newts, includes 32 nominal species ranging across eastern Himalaya, eastern Nepal, northern India, Bhutan, Myanmar, central to southern China (including Hainan island), and southwards through Laos to Thailand and Vietnam (Hernandez 2016; Bernardes et al 2020; Pomchote et al 2020a, 2020b; Poyarkov et al 2021a). All known species are terrestrial and micro-endemic, regarded mostly as niche specialists that are generally found at middle to high elevations in subtropical, moist, forested environments. These provide a relatively narrow thermal range (15−24.0 °C) with a high annual rainfall, especially during the monsoon season, which ensures favorable breeding conditions and survival of Tylototriton species (Hernandez et al 2018). Several recent phylogenetic studies have revealed the presence of undescribed cryptic lineages, which might represent independent species, in South-east Asia, especially in the Indochina region (Wang et al 2018; Zaw et al 2019; Bernardes et al 2020; Pomchote et al 2020a, 2020b; Poyarkov et al 2021a)

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Conclusion