Researchers report the discovery of an ancient species of Old World monkey, providing insights into a form of dental evolution. Knowledge about the origin and evolution of Old World monkeys, a member of the family Cercopithecoidea, is limited because of a meagre fossil record that until now consisted of only two fossilized teeth from the first approximately 12 million years of the group's existence. John Kappelman and colleagues found 22 million-year-old cercopithecoid dental remains that help fill this longstanding gap in the fossil record. The authors examined the fossil monkey's dentition via phylogenetic analysis, CT scans, and 3D reconstructions. The teeth, which were found at three different sites in Nakwai, Kenya, lacked a trait shared among all modern Old World monkeys, namely bilophodonty, or the presence of two transverse crests that connect the four cusps of a molar. The authors named the species Alophia metios, given that the monkeys did not have lower molar cross lophids. Because Alophia lacked lophs, they probably relied on cusps to process food. The findings suggest that Alophia may have fed on hard objects, such as fruits and seeds. Monkeys may have evolved bilophodonty when they began incorporating soft leaves into their diet, according to the authors.
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Article #18-15423: "Primitive Old World monkey from the earliest Miocene of Kenya and the evolution of cercopithecoid bilophodonty," by D. Tab Rasmussen et al .
MEDIA CONTACT: John Kappelman, University of Texas at Austin, TX; tel: 512-471-0055; email: jkappelman@austin.utexas.edu ; Ellen R. Miller, Wake Forest University, Winston Salem, NC; tel: 336-473-0708; email: millerer@wfu.edu ; Mercedes Gutierrez, University of Minnesota, Minneapolis, MN; tel: 612-625-5902; email: mmgutier@gmail.com ; James B. Rossie, Stony Brook University, NY; tel: 631-632-7620; email: james.rossie@stonybrook.edu
Proceedings of the National Academy of Sciences