DNA uncovers identical deadly sea snakes

U. QUEENSLAND (AUS) — A lethal beaked sea snake is actually two separate species that have evolved to look exactly alike, report researchers.

The University of Queensland’s Associate Professor Bryan Fry says the Australian and Asian beaked sea snakes were originally thought to be from the same species, however, in comparing their DNA, the research team has found these two snakes are unrelated.

Australian and Asian beaked sea snakes are two unrelated species despite their identical appearances. (Credit: U. Queensland)


“This mix-up could have been medically catastrophic, since the CSL sea snake anti-venom is made using the venom from the Asian snake based on the assumption that it was the same species,” says Fry.

“Luckily, the anti-venom is not only very effective against the Australian new species but actually against all sea snakes since they all share a very stream-lined fish-specific venom.”

Fry says the finding was an example of a situation where two species evolved separately but ended up looking similar, known as the convergent phenotypic evolution phenomenon.

Fry says that the ‘beaked’ morphology of the species could be associated with the extremely specialized niche the snakes occupy, even though both species evolved from different ancestors and were not even close relatives.

He says the two species occupy the same specialized habitat of silt-filled shallows of tropical estuaries throughout the Asian and Australian regions.

These snakes are responsible for the majority of deaths and injuries to fishermen handling nets in these habitats.

As Fry and colleagues from the University of Adelaide report in Molecular Phylogenetics & Evolution, the Asian snake will retain the original name Enhydrina shistosa.

The Australian beaked sea snake has been given the scientific name Enhydrina zweifeli, which identifies the region in New Guinea where it is found.

The new snake will be placed in a separate genus from the true Enhydrina genus in a follow-up publication, which will resolve the complex higher order relationships of sea snakes.

Source: University of Queensland