On Wednesday, March 28th, Drexel University in Philadelphia announced that scientists had discovered a new species of fossil fish. This new species, Holoptychius bergmanni, was a sarcopterygian or a lobe-finned fish. Lobe-finned fish, such as the coelacanth, differ drastically from actinopterygian, or ray-finned fish. Ray-finned fish have delicate fins that fan out from bony spines, while lobe-finned fish have fat, fleshy lobed fins. Scientists think that sarcopterygian fish are the ancestors to modern tetrapodal, or four-legged, animals.
Another fossil sarcopterygian, Tiktaalik roseae, was discovered in 2008 in northern Canada by Drs. Ted Daeschler (Drexel University), Neil Shubin (University of Chicago) and the late Farish A. Jenkins (Harvard University) and was dated to about 375 million years old. The H. bergmanni fossils were found in northern Canada by the same team that found Tiktaalik, as well as Dr. Jason Downs (Swarthmore College), and is thought to have lived at the same time and in the same environment as Tiktaalik. Tiktaalik and H. bergmanni were large predatory fish, and it is possible that the two species even competed against each other for food. In life, H. bergmanni would have been between two and three feet long.
Both of these fish lived during the Devonian period, a time when large swaths of North America, and much of the world, were covered by shallow seas. According to Dr. Daeschler, “We call it a ‘fish-eat-fish world’, an ecosystem where you really needed to escape predation.” Why is this discovery so important? Dr. Jason Downs suggests that these discoveries will help scientists to better understand the transition from finned to limbed vertebrates.
The scientists plan to return to Ellesemere Island in Canada to search for fossils older than H. bergmanni and Tiktaalik in the summer of 2013.
Holoptychius bergmanni was named in honor of the late Martin Bergmann. Martin Bergmann was the director of the Polar Continental Shelf Program (PCSP) and was killed in a plane crash in 2011.