2009-04-23 – Puijila darwini: Anello mancante nell`evoluzione dei Pinnipedi (missing link in pinniped evolution)
http://nature.ca/puijila/index_e.cfm (Official home page)
http://www.eurekalert.org/pub_releases/2009-04/cmon-feo042009.php (good scientific description of the discovery)
Fossil of a walking seal found
Remains of a previously unknown mammal could represent a missing link in pinniped evolution
: Wednesday, April 22nd, 2009
- Researchers discovered remains of a previously unknown pinniped in the Canadian Arctic. (Inset shows bones that were found.) The fossilized skeleton was about 65 percent complete. (Illustration fills in the missing pieces.)
A fossilized skeleton of what researchers are calling a walking seal has been uncovered in the Canadian Arctic. The remains of this previously unknown mammal could shed light on the evolution of pinnipeds, the group that includes seals, sea lions and walruses, researchers report in the April 23 Nature.
The animal, named Puijila darwini, had a long tail and an otterlike body with webbed feet and legs like a terrestrial animal, the researchers report. But P. darwini also had a pinniped-like skull.
“We realized there was no way this was an otter,” says study coauthor Natalia Rybczynski of the Canadian Museum of Nature in Ottawa. The walking seal probably lived about 20 million years ago and was adept at moving both on land and in water, the team reports.
Researchers describe Puijila darwini (illustration shown) as a walking seal, with the legs of a terrestrial animal, a seal-like skull and webbed feet.
Scientists had theorized that pinnipeds evolved from land-dwelling ancestors but had little fossil evidence to support that claim. The new finding could be the missing link in pinniped evolution, the researchers report.
“This is a fantastic discovery,” comments evolutionary biologist Annalisa Berta of San Diego State University.
The finding may also indicate that the Arctic was a geographic center for pinniped evolution, the researchers speculate.
But, Berta notes, other early pinnipeds have been discovered in the North Pacific and Eurasia. “We can’t yet conclude the Arctic was the area of origin for pinnipeds,” Berta says.
The Associated Press – 22-apr-2009
One expert called it “a fantastic discovery” that fills a crucial gap in the fossil record. The 23 million-year-old creature was not a direct ancestor of …
Non c'è ancora nessun commento.