Thursday, October 25, 2012

A new egg-eating sea snake in the genus Apiysurus

A new species of egg-eating sea snake, Aipysurus mosaicus from northern Australia and southern New Guinea has been described by Sanders et al (2012). A. mosaicus was previously considered an allopatric population of A. eydouxii, which occurs throughout the Sunda Shelf and in New Guinea. Molecular analyses reveal these two species to be sister lineages with a deep phylogenetic divergence exceeding that of all other sampled species pairs in Aipysurus. Aipysurus mosaicus is also distinguished from A.eydouxii by morphological characters: number of ventral scales, color pattern (e.g. number and shape of transverse body bands), internal soft anatomy (e.g. position of heart in relation to ventral scales), and skeletal morphology (e.g. shape of nasal and caudal neural spines). Additional sampling is needed to clarify the extent of geographic contact between A. eydouxii and the new species in New Guinea where they appear to be sympatric.

The new sea snake was found by chance by two research colleagues, Johan Elmberg of Sweden and Arne Rasmussen of Denmark, when they were examining formalin-filled jars of snakes at the Natural History Museum in Copenhagen. They found two sea snakes with the same name on the label, which had been there since being sent to Denmark by collectors in the 1800s. "But they looked different and didn't seem to belong to the same group of snakes," Johan Elmberg said in the statement from Kristianstad University in southern Sweden. "After comparing the sea snakes with other similar species in other museums in Europe it was even more obvious that we had found a new distinct sea snake," he said. The Mosaic sea snake is named after its unusually patterned skin, which looks like a Roman floor mosaic. It "never goes ashore and now that its identity is known it is apparent that it is relatively common in the sea in northern Australia and southern New Guinea," Elmberg said. He said the presence of sea snakes was a good sign. "Sea snakes are a good indicator of how the coral reefs and other precious ecosystems are doing. If there are snakes left in the environment it shows that the reefs are healthy and intact," he explained. Unlike some other sea snakes which have strong venom, the Mosaic sea snake is "virtually harmless," Elmberg said, adding that the species is unusual in that it feeds on fish eggs, and therefore has only very small fangs.

Kate L. Sanders et al. 2012. Aipysurus mosaicus, a new species of egg-eating sea snake (Elapidae: Hydrophiinae), with a redescription of Aipysurus eydouxii (Gray, 1849). Zootaxa 3431: 1–18.

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