Sea Snakes: Pacific 70, Atlantic 0

The banded sea snake (Laticauda colubrina) is venomous but relatively docile.

WHILE THERE ARE NEARLY 70 SPECIES OF SEA SNAKES in the Pacific and Indian Ocean basins, there are exactly none in the Caribbean and tropical Atlantic. Even though sea snakes almost certainly could prosper in the warm Caribbean tropics, their absence is a factor of timing, geography and ocean currents.

“WHY ARE THERE NO SEA SNAKES IN THE ATLANTIC? was a question explored in a recent article in the journal Bioscience. Unfortunately, anything beyond the article’s Abstract was behind a paywall.  Fortunately, it was written by a team of scientists mostly from the Florida Museum of Natural History, based at the University of Florida, and the Museum published its own version, an informative article called…  Why Are There No Sea Snakes in the Atlantic?” 

BRIEFLY, IT DEVELOPS THAT SEA SNAKES ARE:  1) The most diverse and successful reptiles in the oceans in terms of species; 2) Found throughout the Indo-Pacific basin, in areas as widespread as Japan, South Africa and Central America; 3) Relatively late arrivals on the evolutionary scale – the first species appeared in the Coral Triangle (or, the Triangle of Diversity) in the South Pacific six to eight million years ago (mya), with most species arriving one to three mya.

SINCE THE ISTHMUS OF PANAMA had been pushed up from the seafloor, closing off any connection between the Pacific and Caribbean basins between four and five mya, sea snakes would have arrived at Central American too late to spread into the Caribbean. And they are prevented from traveling west past the tip of South Africa because of cold currents rising up from Antarctic regions, which would kill them.

PRINCIPAL SOURCE:  Why Are There No Sea Snakes in the Atlantic?Florida Museum of Natural History

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