Photo by: Purwo Kuncoro

New fossil ape discovered in India

Chris Gilbert searching for fossils near Ramnagar, India. Photo credit: Biren Patel.

A 13-million-year-old fossil unearthed in northern India comes from a newly discovered ape, the earliest known ancestor of the modern-day gibbon. The discovery was made by Leakey Foundation grantee Christopher C. Gilbert, Hunter College. It fills a major void in the ape fossil record and provides important new evidence about when the ancestors of today’s gibbon migrated to Asia from Africa.

The findings were published on September 9, 2020, in the Proceedings of the Royal Society B.

CT scan images of Kapi ramnagarensis in various views.

The fossil, a complete lower molar, belongs to a previously unknown genus and species (Kapi ramnagarensis) and represents the first new fossil ape species discovered at the famous fossil site of Ramnagar, India, in nearly a century. 

Gilbert’s find was serendipitous. Gilbert and team members Chris Campisano, Biren Patel, Rajeev Patnaik, and Premjit Singh were climbing a small hill in an area where a fossil primate jaw had been found the year before. While pausing for a short rest, Gilbert spotted something shiny in a small pile of dirt on the ground, so he dug it out and quickly realized he’d found something special.

Fossiliferous deposits near Ramnagar, India where Kapi ramnagarensis was discovered. The fossil was excavated from the mound near the center of the picture. Photo credit: Chris Gilbert.

“We knew immediately it was a primate tooth, but it did not look like the tooth of any of the primates previously found in the area,” he said. “From the shape and size of the molar, our initial guess was that it might be from a gibbon ancestor, but that seemed too good to be true, given that the fossil record of lesser apes is virtually nonexistent. There are other primate species known during that time, and no gibbon fossils have previously been found anywhere near Ramnagar. So we knew we would have to do our homework to figure out exactly what this little fossil was.”

The field team in 2015 that discovered Kapi ramnagarensis, from left: Dr. Ningthoujam Premjit Singh (Panjab University), : Dr. Rajeev Patnaik (Panjab University), Dr. Chris Gilbert (Hunter College, CUNY), Dr. Biren Patel (USC), and Dr. Chris Campisano (Arizona State Univ.). Photo credit: Chris Gilbert.

Since the fossil’s discovery in 2015, years of study, analysis, and comparison were conducted to verify that the tooth belongs to a new species, as well as to accurately determine its place in the ape family tree. The molar was photographed and CT-scanned, and comparative samples of living and extinct catarrhine primate teeth were examined to highlight important similarities and differences in dental anatomy.

“What we found was quite compelling and undeniably pointed to the close affinities of the 13-million-year-old tooth with gibbons,” said Leakey Foundation grantee Alejandra Ortiz. “Even if, for now, we only have one tooth, and thus, we need to be cautious, this is a unique discovery. It pushes back the oldest known fossil record of gibbons by at least five million years, providing a much-needed glimpse into the early stages of their evolutionary history.”

Map illustrating the location of Kapi (black star) relative to modern (dark green) and historical (light green) populations of lesser apes and the approximate distribution of early fossil apes in East Africa (blue triangles). Green triangles mark the location of previously discovered fossil hylobatids Bunopithecus and Yuanmoupithecus. Note that Kapi ramnagarensis is millions of years older than any previously known fossil hylobatid and found in a geographic region intermediate between earlier apes in Africa and other known hylobatids in East Asia. Illustration by Luci Betti-Nash.

In addition to determining that the new ape represents the earliest known fossil gibbon, the age of the fossil, around 13 million years old, is contemporaneous with well-known great ape fossils, providing evidence that the migration of great apes, including orangutan ancestors, and lesser apes from Africa to Asia happened around the same time and through the same places.

“I found the biogeographic component to be really interesting,” said Chris Campisano. “Today, gibbons and orangutans can both be found in Sumatra and Borneo in Southeast Asia, and the oldest fossil apes are from Africa. Knowing that gibbon and orangutan ancestors existed in the same spot together in northern India 13 million years ago, and may have a similar migration history across Asia, is pretty cool.”

The research team plans to continue research at Ramnagar, having recently received a grant from the National Science Foundation to continue their ongoing search for ape fossils. 


New Middle Miocene Ape (Primates: Hylobatidae) from Ramnagar, India fills major gaps in the hominoid fossil record

Christopher C. Gilbert, Alejandra Ortiz, Kelsey D. Pugh, Christopher J. Campisano, Biren A. Patel, Ningthoujam Premjit Singh, John G. Fleagle and Rajeev Patnaik

Published: September 9, 2020

https://doi.org/10.1098/rspb.2020.1655/


Article coauthors include Chris Gilbert* Anthropology, Hunter College, and the Graduate Center (both of the City University of New York); Alejandra Ortiz*, New York University and the Institute of Human Origins, Arizona State University; Kelsey D. Pugh*, American Museum of Natural History; Christopher J. Campisano*, Institute of Human Origins and the School of Human Evolution and Social Change, Arizona State University; Biren A. Patel*, Keck School of Medicine and the Department of Biological Sciences, University of Southern California; Ningthoujam Premjit Singh, Department of Geology, Panjab University; John G. Fleagle*, Department of Anatomical Sciences, Stony Brook University; and Rajeev Patnaik, Department of Geology, Panjab University

* Indicates a Leakey Foundation grantee

This research at Ramnagar was funded by The Leakey Foundation, the PSC-CUNY faculty award program, Hunter College, the AAPA professional development program, the University of Southern California, the Institute of Human Origins (Arizona State University), and the National Science Foundation.  Indian colleagues are further supported by the Indian Ministry of Earth Sciences and Science and Engineering Research Board.




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