Thursday, February 19, 2015

A second chance for two Australian sea snakes (Aipysurus) presumed extinct

Photographs A,C: A. apraefrontalis (SAMA R68142)
from Ashmore Reef; and B, D:Aipysurus foliosquama
(WAM R150365) from Barrow Island.
One in five reptile species are estimated to be at risk of extinction and many are thought to have become extinct within the last 50 years. Threats to reptiles include habitat loss and degradation, climate warming, and overharvest for food, traditional medicines and leather. Rediscoveries of presumed extinct species inspire optimism, but many such rediscovered species remain at immediate risk of extinction and require urgent assessment of population status and threats in their remaining range to guide management actions.

In a new paper published in PLoS ONE, Sanders, Schroeder, Guinea and Rasmussen (2015) report on the critically endangered leaf-scaled (Aipysurus foliosquama) and short-nosed (A. apraefrontalis) sea snakes. Species currently recognized only from Ashmore and Hibernia reefs ~600km off the northwest Australian coast. Steep population declines in both species were documented over 15 years and neither has been sighted on dedicated surveys of Ashmore and Hibernia since 2001. The authors examine specimens of these species that were collected from coastal northwest Australian habitats up until 2010 (A. foliosquama) and 2012 (A. apraefrontalis) and were either overlooked or treated as vagrants in conservation assessments. Morphological variation and mitochondrial sequence data confirm the assignment of these coastal specimens to A. foliosquama (Barrow Island, and offshore from Port Hedland) and A.apraefrontalis (Exmouth Gulf, and offshore from Roebourne and Broome). Collection dates, and molecular and morphological variation between coastal and offshore specimens, suggest that the coastal specimens are not vagrants as previously suspected, but instead represent separate breeding populations. The newly recognized populations present another chance for leaf-scaled and short-nosed sea snakes, but the coastal habitats in northwest Australia are threatened by infrastructure developments and sea snakes are presently omitted from environmental impact assessments for industry. The authors note further studies are urgently needed to assess these species’ remaining distributions, population structure, and extent of occurrence in protected area.

Citation

Sanders KL, Schroeder T, Guinea ML, Rasmussen AR (2015) Molecules and Morphology Reveal Overlooked Populations of Two Presumed Extinct Australian Sea Snakes (Aipysurus: Hydrophiinae). PLoS ONE 10(2): e0115679. doi:10.1371/journal.pone.0115679.




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