UT researchers find new species of ancient monkey that fills in evolutionary gap

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Photo Credit: Jeb Milling | Daily Texan Staff

UT researchers discovered a new species of ancient monkeys during field work in Kenya, bridging a gap in the history of old world monkey evolution.

The new species, called Alophia metios , was discovered by a team led by John Kappelman, a geology and anthropology professor at UT. The research is a continuation of the work conducted by Tab Rasmussen, an anthropology professor from Washington University in St. Louis who led the project before his death.

“There was basically a gap (in the fossil records) going from about 20 million all the way back to 30 million (years) ... just this empty hole,” Kappelman said.

The Alophia metios discovery is noteworthy because the species appears in the middle of this gap, said anthropology graduate student Ben Rodwell.

“What’s interesting in terms of morphology (is) the structure of the tooth,” said Ellen Miller, an anthropology professor at Wake Forest University who was a member of the team. “Alophia is actually more primitive than (monkeys) found earlier in time.” 

 

The name “Alophia” was chosen because, unlike earlier species, Alophia metios do not have lophs in their teeth, Kappelman said. Lophs are crests in the teeth that run between the points, or cusps. 

“For most Old World monkeys, the lophs are one of the features which link all of them together,” Kappelman said. 

Bilophodont, or two lophs in each of the teeth, is a distinguishing feature of modern Old World monkeys, which are primates living in the eastern hemisphere.

“Bilophodonty is something that works really well to process leaves,” Kappelman said. “Without bilophodonty ... it probably ate harder foods like nuts, hard fruits ... but not leaves.”

The distinction in diet is important for understanding when divisions within living Old World monkeys began to appear.

“There’s one big division, one that’s mainly folivorous (leaf-eating) and one that’s mainly frugivorous (fruit-eating),” Rodwell said. “This is kind of the beginnings of that shift, then eventual partitioning, of those two main groups.”

Kappelman and his team plan to go back out into the field later this year in search of more fossils from Alophia metios to further their understanding of the species.

“These projects are large collaborative efforts ... between the different countries,” Kappelman said. “When you work with people under these conditions, you have the professional relationships but also the friendships that are built, and that’s really important.”