Tuesday, October 22, 2019

[Herpetology • 2019] Tylototriton kachinorum • A New Species of Crocodile Newt, Genus Tylototriton (Caudata, Salamandridae) from the Mountains of Kachin State, northern Myanmar


Tylototriton kachinorum  
Zaw, Lay, Pawangkhanant, Gorin & Poyarkov, 2019


Abstract
 We describe a new species of the genus Tylototriton from Ingyin Taung Mt., Mohnyin Township, Kachin State, Myanmar, based on morphological and molecular evidence. The new species is assigned to the subgenus Tylototriton s. str. and is clearly distinct from all known congeners by the following characters: medium body size; thin, long tail, lacking lateral grooves; rough skin; truncate snout; wide, protruding supratemporal bony ridges on head, beginning at anterior corner of orbit; weak, almost indistinct sagittal ridge; long, thin limbs, broadly overlapping when adpressed along body; distinct, wide, non-segmented vertebral ridge; 13 or 14 rib nodules; brown to dark-brown background coloration with dull orange-brown to yellowish-brown markings on labial regions, parotoids, rib nodules, whole limbs, vent, and ventral tail ridge. We also briefly discuss biogeography and species diversity of the genus Tylototriton in Myanmar.


Key words: Tylototriton kachinorum sp. nov., mtDNA genealogy, ND2, 16S rRNA, Shan, Biogeography, Endemism, Taxonomy




Figure 4: Holotype of Tylototriton kachinorum sp. nov. (ZMMU A5953, male) in situ 
(Photo by Nikolay A. Poyarkov and Than Zaw)



Tylototriton kachinorum sp. nov.



Diagnosis: The new species is assigned to the genus Tylototriton based on molecular data and by the following combination of morphological attributes: (1) presence of dorsal granules, (2) dorsolateral bony ridges on head, (3) presence of dorsolateral series of knob-like warts (rib nodules); and (4) absence of quadrate spine (Figure 2). Tylototriton kachinorum sp. nov. is distinguished from all other congeners by a combination of the following morphological attributes: (1) medium body size, adult SVL 62.3–74.1 mm in males, 72.5– 84.8 mm in females; (2) tail thin and long, longer than body in both sexes, lacking lateral grooves; (3) skin rough with fine granules; (4) snout truncate in dorsal view; (5) supratemporal bony ridges on head wide, protruding, beginning at anterior corner of orbit; (6) sagittal ridge on head very weak, almost indistinct; (7) limbs long and thin, tips of forelimb and hindlimb broadly overlapping when adpressed along body; (8) vertebral ridge distinct, wide, non-segmented; (9) rib nodules weakly distinct, 13 – 14 along each side of body; (10) background coloration brown to dark-brown; (11) labial regions, parotoids, rib nodules, whole limbs, vent, ventral tail ridge with dull orange-brown to yellowish-brown markings.

The new species is also markedly distinct from all congeners for which comparable sequences are available of ND2 (P≥ 5.3%) and 16S rRNA (P≥2.4%) mitochondrial DNA genes.


Etymology: The specific name “kachinorum is a Latin adjective in the genitive plural (masculine gender), derived from the name of the Kachin people who inhabit the montane areas of northern Myanmar and adjacent territories (Kachin Hills), including the type locality of the new species.




Recommended vernacular name: We recommend the following name in English: Kachin Crocodile Newt. Recommended vernacular name in Burmese (Myanmar) language: Kachin Yae Poke Thin.


Figure 6: Lateral (A), dorsal (B), and ventral (C) views of larval specimen (ZMMU A5957; Grosse (2013) stage 40) of Tylototriton kachinorum sp. nov. in life Scale bar: 3 mm. 
Photos by Nikolay A. Poyarkov


   


Than Zaw, Paw Lay, Parinya Pawangkhanant, Vladislav A. Gorin and Nikolay A. Poyarkov, Jr. 2019.  A New Species of Crocodile Newt, Genus Tylototriton (Amphibia, Caudata, Salamandridae) from the Mountains of Kachin State, northern Myanmar. Zoological Research. 40(3); 151-174. DOI: 10.24272/j.issn.2095-8137.2019.043