Thursday, April 2, 2020

[Herpetology • 2020] Emydocephalus orarius • A New Species of Turtle-headed Sea Snake (Emydocephalus: Elapidae) endemic to Western Australia

Emydocephalus orarius 
Nankivell, Goiran, Hourston, Shine, Rasmussen, Thomson & Sanders, 2020

Photo: Brad Maryan

We describe a new species of turtle-headed sea snake Emydocephalus orarius sp. nov. (Elapidae) from Western Australia’s Coral Coast, Pilbara and Kimberley regions. Phylogenetic analysis of mitochondrial markers places the new species as the sister lineage to the two currently recognised species in Emydocephalus: E. annulatus from the Timor Sea reefs and Coral Sea, and E. ijimae from the Ryukyu Islands. Analysis of nuclear SNP data from the new species and E. annulatus from Australia and New Caledonia provides additional independent evidence of their evolutionary distinctiveness. The new taxon is usually morphologically diagnosable from its congeners using a combination of scalation and colour pattern characters, and appears to reach greater total lengths (>1 m in the new species versus typically ~80 cm in E. annulatus/E. ijimae). The new species is known largely from soft-bottomed trawl grounds, unlike E. annulatus and E.ijimae which usually inhabit coral reefs. The discovery of this new species brings the number of sea snake species endemic to Western Australia to six.

Keywords: Reptilia, Hydrophiinae, marine,mitochondrial, RADseq, Australia, systematics

Emydocephalus orarius

Etymology. The species epithet ‘orarius’ (Latin, ‘coastal’) refers to the coastal Western Australian distribution of the new species. Other species of Emydocephalus are found on coral reefs, typically on clear oceanic reefs some distance away from coastlines of major landmasses. 

James H. Nankivell, Claire Goiran, Mathew Hourston, Richard Shine, Arne R. Rasmussen, Vicki A. Thomson and Kate L. Sanders. 2020. A New Species of Turtle-headed Sea Snake (Emydocephalus: Elapidae) endemic to Western Australia. Zootaxa. 4758(1); 141–156. DOI:  10.11646/zootaxa.4758.1.6