Monday, Mar 11, 2013
A partial skull of a new fisher species was recently found at John Day Fossil Beds National Monument, near Dayville, Oregon. This discovery, described in the current issue of the Journal of Vertebrate Paleontology, represents the earliest record of a fisher in the world. Between 7.05 and 7.3 million years old, this find is more than 5 million years earlier than other records of fishers in North America.
The living fisher is an elusive member of the weasel family that occurs across the northern United States and Canada, living in dense forest environments. Fishers and their relatives have a very poor fossil record. Previously, the earliest known records of fishers in North America were from several sites in the eastern United States, less than 2 million years old. Fisher fossils are also known from China and Mongolia, and some may be almost as old as this new find, but they are not well dated.
Due to their rarity, the origin and evolutionary history of fishers is unclear, as is the origin of the related wolverines and martens. The new species, Pekania occulta, shows notable similarity to the living fisher species, Pekania pennanti, but its teeth are substantially more robust. Recent genetic studies have demonstrated fishers are most closely related to wolverines, and this find is similar in age to the estimated divergence time of fishers from wolverines and martens.
The robust nature of the new fossil species may reflect this history, suggesting that this may be similar to the ancestor of all of these animals.
Finds like this help paleontologists to better reconstruct past environments. Much like today, eastern Oregon of 7 million years ago is thought to have been mostly a sagebrush/bunchgrass steppe environment. Some of the animals in Oregon at that time were very different than today; there were mastodons, rhinos, camels, saber tooth cats, and giant ground sloths. Other animals like the fisher, along with beavers, foxes, ground squirrels, and pronghorn, would be very familiar to people living in Oregon.
The new fisher and recent beaver finds from the Rattlesnake Formation, as well as petrified wood fragments, suggest the region had heavily forested areas in the past, potentially in riparian areas and valleys along ancient rivers and streams.
Paleontologists have been studying John Day Basin for almost 150 years, but there is still much more to learn about Oregon’s past. New finds like this occur regularly, highlighting the importance of preserving fossils on public lands, which both aid scientific research and allow the public to enjoy these valuable natural resources.
The specimen will be going on display in the park’s Thomas Condon Paleontology Center. A noted above, more information on the can be found in the current issue of the Journal of Vertebrate Paleontology.