18-Ago-2011 - New species is eel-equivalent of the coelacanth




Protoanguilla palau: 'first eel'. Photo by: Jiro Sakaue.
The ocean holds endless surprises still. In an underwater cave off the Pacific island nation of Palau, reachers have made an astounding discovery: an eel species unknown to science that harkens back 200 million years. The new species, described in the Proceedings of the Royal Society B as an 'enigmatic, small eel-like fish', sports anatomical features that differentiate it from the over 800 known species of eel surviving today.

"The equivalent of this primitive eel, in fishes, has perhaps not been seen since the discovery of the coelacanth in the late 1930s," says Dave Johnson, ichthyologist at the Smithsonian's National Museum of Natural History and lead author of the team's research, in a press release. Before its discovery in the 1930s, the coelacanth was only known from fossils dating back 70 million years. However, even the eel fossil record has never shown anything quite like this.

The new species, named Protoanguilla palau, sports a second upper jaw bone and less than 90 vertebrate. These two features have only been seen in fossil eels going going to the Cretaceous. But another feature breaks all the rules: the animal has a complete set of 'rakers' in its gill arches, which has only been seen in bony fish, never before in eels either alive or fossilized. To determine its truly relationship to eels and bony fish, the researchers analyzed the animal's mitochondrial DNA and found that it is a 'true eel'. The animal likely appeared some 200 million years ago, just at the very end of the Triassic period.
Source: mongabay.com

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