REMAINS OF ANCIENT PRIMATE FOUND IN OREGON
Scientists have unearthed fossil teeth and a jaw fragment1 in Oregon. And these have helped flesh out2
the features of an ancient animal that once lived in North America. A new species of primate, it had
features similar to a modern lemur’s.
Primates are a group of mammals that includes monkeys, lemurs, gorillas and humans. The Sioux are a
tribe of Native Americans. The newfound primate’s genus3 name comes from a Sioux term for monkey:
Ekgmowechashala. These last nonhuman primates to live in North America vanished around 26 million
years ago. No other primates lived in North America until humans arrived well over 25 million years
later. This timeline comes from the new study.
Joshua Samuels works for the National Park Service in Kimberly, Ore. As a paleontologist, he studies
ancient fossils. He and his colleagues4 dug up the ancient primate bones between 2011 and early 2015.
They found two complete teeth, two partial teeth and a jaw fragment.
All came from rocky sediment at Oregon’s John Day Formation. This rock layer contains fossils from
between 30 million and 18 million years ago. A tooth and jaw fragment from the same species had been
found there previously. All the fossils belong to a new species of Ekgmowechashala, the researchers say.
Partial5 jaws and teeth of a related species had turned up at sites in South Dakota and Nebraska.
The scientists figured out the age of the fossils based on their position between layers of volcanic ash.
The ages of those layers was already known. That let the scientists determine that the new fossils must
be between 28.7 million and 27.9 million years old.
Where did the primates come from?
Millions of years ago, land connected what is now Alaska and Russia. The ancient primates probably
crossed that “land bridge” around 29 million years ago, the researchers now say. That journey would
have taken place some 6 million years after other North American primates had died out.
Samuels says the new fossils appear to resemble those from a 34-million-year-old primate from
Thailand, in Southeast Asia. The new fossils also are similar to a 32-million-year-old primate from
Pakistan, which lies between the Middle East and India.
Erik Seiffert is a paleontologist at Stony Brook University in New York. He suggested an Asian–North
American primate connection back in 2007. But Samuels and his team “have laid out the evidence in
more detail,” Seiffert now says.
Some researchers suspect Ekgmowechashala’s closest present-day relatives would have been tarsiers.
These small primates live on islands in Southeast Asia. Other scientists think the now extinct North
American primates were more closely related to lemurs. They exist only in Madagascar. It’s an island off
of the East Coast of southern Africa.
K. Christopher Beard agrees with Samuels’ team that Ekgmowechashala is likely more related to the
lemurs. A paleontologist, Beard works at the University of Kansas in Lawrence. But he argues that to
confirm this, scientists need to find ankle bones. They should point out whether the ancient6 primate
species had a greater kinship7 to lemurs or to tarsiers.
GLOSS WORDS
1.
2.
3.
4.
5.
6.
7.
fragment – small piece
flesh out – make clearer
genus – scientific grouping
colleagues – coworkers
partial – Parts of
ancient – very old
kinship – relationship