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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.
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.