A species that hasn’t shown significant change over a very long period of time is known as a “living fossil.” Scientists love studying these species because they give insight into what the world was like millions of years ago. However, it is often difficult to connect the living fossils to the related species of prehistoric times. John Graf, a researcher at Southern Methodist University in Texas, thinks he has done just this. Graf and his research group are analyzing the bones of a 100-million-year-old coelacanth, a member of an order of fish that includes two species of living fossils. Coelacanths are ancient fish with only a few defining characteristics: lobed fins, an electrosensory organ, extra thick scales, and hinged joint that allowed the fish to swallow very large prey. There are 40 known species of coelacanths, and the two that exist today as living fossils are essentially the same as coelacanths that existed 320 million years ago. The new species was found by Robert Reid in the 1980s in Forth Worth, Texas; and has been dubbed Reidus hilli. Graf and his associates have only skull fragments to study, but believe that R. hIlli was probably about one-and-a-half feet long. Compared to other coelacanths at the time, which grew up to 10 feet long, Reidus was somewhat of a runt. Modern coelacanths measure up to seven feet long. The researchers think this new species was an in-between in the evolutionary lineage of older coelacanths and today’s living fossils.

coelocanth
The fossilized skull of the new coelocanth, Reidus hilli, from Forth Worth, Texas (image by Dale Winkler / Southern Methodist University).

Learn more about coelacanths at National Geographic onlline.

Discover more about this study at News National Geographic.com.

Read the original article in the journal Historical Biology.

Published On: November 27, 2012

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