A missing geographic link in the distribution of the genus Echinotriton (Caudata: Salamandridae) with description of a new species from southern China

Abstract

Disjunct geographic distribution of a species or a group of species is the product of long-term interaction between organisms and the environment. Filling the distributional gap by discovery of a new population or a species has significant biogeographic implications, because it suggests a much wider past distribution and provides evidence for the route of range expansion/contraction. The salamandrid genus Echinotriton (commonly known as spiny salamanders, spiny newts, or crocodile newts) has two species that are restricted to two widely separated areas, one in eastern Zhejiang province, China and the other in the Ryukyu Archipelago of Japan. It has been hypothesized that Echinotriton was once continuously distributed between the two areas through a historical land bridge that connected mainland China, Taiwan, and the archipelago. Finding fossils or relic populations along the postulated distribution are strong evidence for the hypothesis. Hundred-twenty-two years after the description of E. andersoni and eight-one years after that of E. chinhaiensis, we discover a third species of Echinotriton in southern China, which fills the distributional gap of the former two species. Species status of the new species is confirmed through molecular phylogenetic analysis and morphological comparison. Mitochondrial DNA indicates that the new species is sister to E. chinhaiensis, while nuclear DNA does not support this relationship. The new species has a very large quadrate projection, a single line of lateral warts pierced by distal rib extremities, normally developed 5th toes, and conical skin tubercles. Our discovery supports the hypothesis that there was a continuous distribution of Echinotriton from eastern coastal China to the Ryukyu Archipelago. We suggest that other species of this genus may also be found in Taiwan. Due to the rarity of this new species, we urge all hobbyists to refrain themselves from collecting this salamander or leaking locality information if encountered, and boycott any trading.

Two new species of the genus Goniurosaurus (Squamata: Sauria: Eublepharidae) from southern China

“…They highlighted Goniurosaurus species as taxa likely to become commercial commodities, and called for caution in disclosing exact localities in describing new species. Hou et al (2014) also reported similar cases of poaching on restricted-range herpetofauna for the pet market following disclosure of locality information in formal publications.…”

Estimating the global trade in Southeast Asian newts

“…Two East Asian newt species have already been extirpated in all or a significant part of their ranges (Lau et al, 2007), and at least one Southeast Asian newt is perilously close to being driven to extinction in the wild primarily due to the pet trade (Stuart et al, 2014). The threat of the illegal pet trade to Asian newts is such that a recent publication describing a new newt species from China, Echinotriton maxiquadratus, did not reveal the collection locality and made the specific request that "all hobbyists…refrain themselves from collecting this salamander or leaking locality information if encountered, and boycott any trading" (Hou et al, 2014;pp 89. ).…”

An Extremely Peramorphic Newt (Urodela: Salamandridae: Pleurodelini) from the Latest Oligocene of Germany, and a New Phylogenetic Analysis of Extant and Extinct Salamandrids

“…Some sources [ 4 , 15 , 29 ] termed the large, sculptured bone that is in broad contact with the posterior end of the maxilla in Chelotriton the quadratojugal, whereas [ 22 ] interpreted this bone in the same taxon as the quadrate. A bone in a comparable position was referred to as the quadrate in Tylototriton and Echinotriton [ 8 , 33 , 45 ], and a separate quadratojugal bone was described neither in these nor in other pleurodelines. In most anatomical studies dealing with the salamander skull, a quadratojugal bone is not identified.…”

“…A rather smooth, triangular piece of bone in the right orbitotemporal fenestra (Figs 8 and 11 ) is connected posteromedially to a fragment of a thicker bone. This could represent the ventromedial process of the maxilla that was sutured to the pterygoid, as in Tylototriton [ 22 ] or Echinotriton [ 8 , 45 ].…”

“…The remains of the ribs are long and attain the length of more than three successive vertebrae. Taking into account the missing proximal portion, they were proportionally longer than the elongate ribs of the Enspel specimens of Chelotriton [ 29 ], as well as those of Echinotriton [ 8 , 45 ] or Palaeopleurodeles [ 11 ]. The first four of the preserved right ribs are straight, whereas the posteriorly following ones are slightly curved ventrally.…”