 |
| Tylototriton ngoclinhensis Phung, Pham, Nguyen, Ninh, Nguyen, Bernardes, Le, Ziegler & Nguyen, 2023 |
Abstract
A new species of the genus Tylototriton is described from Ngoc Linh Mountain, Kon Tum Province, in the Central Highlands of Vietnam based on integrative taxonomy, namely by combining molecular and morphological evidence. Tylototriton ngoclinhensis sp. nov. differs from all other congeners based on morphological data, allopatric distribution, and molecular divergence. In terms of genetic divergence, Tylototriton ngoclinhensis sp. nov. distinctly differs from the sister species T. panhai (6.77%) and from T. ngarsuensis (12.36%) based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. Tylototriton ngoclinhensis sp. nov. is a moderate sized and robust salamander species with large cephalic edges, parotoids, and vertebral ridge orange in coloration. The new taxon differs from its congeners by a combination of the following morphological characteristics: size medium (SVL 60.8–66.5 mm, TL 57.6–61.8 mm in males, and SVL 72.5–75.6 mm, TL 62.9–67.9 mm in females); head longer than wide; parotoids very prominent and enlarged, projecting backwards; tail length shorter than snout-vent length; vertebral ridge large, high and glandular in appearance; 14 large and distinct dorsolateral glandular warts; gular fold present; tips of fore and hind limbs overlapping when adpressed along the body; tips of fingers reaching between eye and nostril when foreleg is laid forward; dorsal surface and lateral sides of the head, upper and lower lips, dorsolateral glandular warts, vertebral ridge, the peripheral area of the cloaca and the ventral edge of the tail orange in coloration; the presence of a distinct black line extending from the posterior end of the eye towards the shoulder. Tylototriton ngoclinhensis sp. nov. is restricted to evergreen montane forests near water bodies on Ngoc Linh Mountain. We suggest that the new species should be classified as Endangered (EN) in the IUCN Red List. This new important discovery represents the eighth Tylototriton taxon described from Vietnam, and at the same time constitutes the southernmost distributional record for the whole genus in Asia.
Key words: Crocodile newt, ND2 gene, Ngoc Linh Mountain, Salamandridae, taxonomy, Tylototriton ngoclinhensis sp. nov.
 |
| Dorsolateral view of Tylototriton ngoclinhensis sp. nov., holotype male (IEBR A.5130), in life. |
 |
| Tylototriton ngoclinhensis sp. nov. in its microhabitat at the type locality. |
Tylototriton ngoclinhensis sp. nov.
Proposed common name: Ngoc Linh Crocodile Newt
Diagnosis: The new species is assigned to the genus Tylototriton and the subgenus Yaotriton based on the results of the molecular phylogenetic analyses and the following combination of morphological attributes: rough skin covered with fine warts, the presence of dorsolateral bony ridges on the head; the presence of dorsolateral glandular warts on the body; quadrate spine absent (Nussbaum and Brodie 1982; Nishikawa et al. 2013a; Le et al. 2015). Furthermore, the species is diagnosed from its congeners by the following combination of morphological characters: (1) size medium (SVL 60.8–66.5 mm, TL 57.6–61.8 mm in males, and SVL 72.5–75.6 mm, TL 62.9–67.9 mm in females); (2) head longer than wide; (3) parotoids very prominent and enlarged, projecting backwards; (4) tail length shorter than the snout-vent length; (5) vertebral ridge large, high, and glandular in appearance (6) 14 distinct dorsolateral glandular warts; (7) gular fold present; (8) tips of fore- and hind limbs overlapping when adpressed along the body; (9) tips of fingers reaching between eye and nostril when foreleg is laid forward; (10) dorsal surface and lateral sides of the head, upper and lower lips, rib nodules, vertebral ridge, peripheral area of the cloaca, and the ventral edge of tail with orange coloration; (11) presence of a distinct black line extending from the posterior end of the eye towards the shoulder.
Etymology: The specific epithet ngoclinhensis refers to the type locality of the new species, Ngoc Linh Mountain in the Central Highlands of Vietnam. As common names, we suggest Ngoc Linh Crocodile Newt (English), Cá cóc sần ngọc linh (Vietnamese).
 |
| Habitat at the type locality of Tylototriton ngoclinhensis sp. nov. on Ngoc Linh Mountain. |
Trung My Phung, Cuong The Pham, Truong Quang Nguyen, Hoa Thi Ninh, Huy Quoc Nguyen, Marta Bernardes, Son Thanh Le, Thomas Ziegler and Tao Thien Nguyen. 2023. Southbound – the Southernmost Record of Tylototriton (Amphibia, Caudata, Salamandridae) from the Central Highlands of Vietnam represents A New Species. ZooKeys. 1168: 193-218. DOI: 10.3897/zookeys.1168.96091