"Living Fossil" Eel Discovered in Palau

"Living Fossil" Eel Discovered in Palau

Amber Williams
Published: 08/23/2011

The saying goes that there’s nothing new under the sun. But under the sea is a different story. Researchers recently discovered a new eel in the Pacific Ocean that they’ve deemed a “living fossil.” It’s so new in fact, that they had to make up a new family, genus, and species to classify it.


(Primitive eel found off the coast of the Republic of Palau. By Jiro Sakaue)

Arguably, the eel isn’t “new,” since the prehistoric creature has been around longer than humans. However, the glimpse it offers into what ancient life may have looked like millions of years ago certainly is. Most of the plants and animals that once inhabited the earth have gone extinct. Sadly, we will never know about many of them because their forms weren’t preserved as fossils. Since fossilized animals lie few and far between on earth’s timeline, any insight into what creatures used to live, and how they may have evolved into the forms we see around us today, are priceless.

A scientist from the Smithsonian Institution in Washington, D.C., came upon the eel in a cave in the Republic of Palau, an island nation about 500 miles east of the Philippines. Around 115 feet deep, the eel gracefully swam (video). At first glance, the researchers debated whether it was actually an eel in the first place. It had a bigger head and a shorter body than eels we know, as well as gill openings around its neck and the beginning of fin rays. It was more of an “eel-like fish,” wrote the scientists in their paper, published in the Proceedings of the Royal Society B.

Gene sequencing revealed that it was indeed a true eel, even though some of its features were more primitive than the defined eels we know today and some even more primitive than the oldest known eel fossils. The recent discovery belongs to the group Anguilliformes, which appears in fossils dating from the Cretaceous period, about 100 million years ago. This eel is now the most primitive living member of that group.

After the scientists compared the anatomy of the new eel to its living and extinct relatives and performed similar comparisons with their DNA, they found that “the living fossil” shares at least 15 characteristics with both. It also shares 7 characteristics with its living relatives that are absent in its extinct brethren. Unlike current eels, though, the new one has cranial bones near the jaw that bear teeth, like other eels from the Cretaceous. Yet it exhibits some unique traits, too. It has gill rakers, which are bony projections that help with filter feeding, and fewer than 90 vertebrae. These are traits even more primitive than the oldest known eel fossil. So, while pop song lyrics may never be completely original, and love stories may be recycled until the end of time, who knows what new tales the earth will tell.

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