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Primate Molar Emerges From Fossil Beds
1/24/98-J. Chapman, JODA Staff
Evidence of the last known primate to inhabit North America prior to humans has recently surfaced among the field collections from the 1997 fossil prospecting season at John Day
Fossil Beds National Monument.
In December, while cataloging the summer's finds, fossil preparator Kelly Cahill
came across a strange molar, unlike any in the monument's museum collection. Monument
paleontologist Ted Fremd identified the 4mm specimen as a lower molar belonging to
Ekgmowechashala (IG-a-moo-we-CHA-sha-la), a small, ancient, lemur-like animal which is extremely rare in the
fossil record. "All of us have been looking for something like this for years," Fremd said.
The genus Ekgmowechashala is classified in the order Primates, sub-order Dermoptera (flying-lemurs), and
has a tooth structure similar to flying squirrels. A jaw fragment with adjacent upper molars (intact M1-M2, broken M3) from the same kind of animal was
previously known from the region, discovered in 1961. A cast of this specimen was used to
positively identify the newly found molar (lower m2) which "fit like a glove," according to Fremd.
The recent find is important because it includes good documentation of the
stratigraphic position of the fossil. Knowing where the fossil was located in the rock allows a date of 25
million years ago to be assigned to it. Other specimens of
Ekgmowechashala from South Dakota had been dated at 28 million years ago and were considered to mark the end of the original
primate lineage in North America. The John Day find confirms that ancient primates were in Oregon 3 million
years after scientists thought they had become extinct.
The newest molar was collected by John Zancanella of the Bureau of Land Management
who was part of an interagency team doing routine prospecting in the fossil beds.
"We try to continuously examine fossil-bearing rocks to collect scientifically
significant fossils on federal lands," stated Fremd. "Otherwise, weathering and other factors may
destroy them." Fremd plans to return with the field crew next summer to the area where the molar
was found in hopes of recovering more evidence of North America's last primate.
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