(By Dr. Joseph D. Lim and Dr. Kenneth Lester Lim)
TEETH millions of years old reveal a new human species, turning the story of evolution upside down.
The new unknown branch of humanity from the depths of time cannot be named yet based on the teeth alone. More fossils are needed before that can happen, reports Arizona State University (ASU) which leads the study published August 13 in the scientific journal Nature.
The fossilized teeth were unearthed by the Ledi-Geraru Research Project in northeastern Ethiopia, eastern Africa.
The prehistoric teeth, which date to between 2.8 million and 2.6 million years ago (Ma), belong to a species that was a member of the genus Australopithecus, the same genus of the famous Lucy fossil discovered in 1974 also in Ethiopia. Lucy was the first evidence that hominins, our ancestors, walked on two legs over 3 million years ago.
This time, the set of fossil teeth suggests that the new member of the human family lived at the time of Homo, the ancestor of Homo sapiens.
About 3 Ma and 2 Ma, two closely related human ancestors shared a critical period in human evolution, according to the new study, pointing out that this was when the genera Homo and Paranthropus first appear in fossil records and a possible ancestor of the Australopithecus afarensis genera disappears.
Homo was present at 2.78 Ma and 2.59 Ma, and Australopithecus at 2.63 Ma.
The new study suggests that Australopithecus and early Homo co-existed as two non-robust lineages in Ethiopia’s Afar Region before 2.5 Ma, and that the fossil record of hominin, man’s ancestors, is more diverse than previously known.
The international team led by scientists at Arizona State University collected 13 fossilized teeth in the research area from 2015 to 2018. The collections at two localities represent a newly discovered species of Australopithecus, says the study’s first author, Brian Villmoare of the Department of Anthropology, University of Nevada Las Vegas.
“This new research shows that the image many of us have in our minds of an ape to a Neanderthal to a modern human is not correct – evolution doesn’t work like that,” says Professor Kaye Reed in a press statement from Arizona State University. “Here we have two hominin species that are together. And human evolution is not linear, it’s a bushy tree, there are lifeforms that go extinct.”
Reed is a paleoecologist who studies the relationships between ancient organisms and environments by analyzing fossils and geological information. A Research Scientist at the Institute of Human Origins and President’s Professor Emerita at the School of Human Evolution and Social Change at Arizona State University, she has been co-director of the Ledi-Geraru Research Project since 2002.
“The new finds of Homo teeth from 2.6-2.8-million-year-old sediments confirms the antiquity of our lineage,” says Villmoare.
“We know what the teeth and mandible of the earliest Homo look like, but that’s it. This emphasizes the critical importance of finding additional fossils to understand the differences between Australopithecus and Homo, and potentially how they were able to overlap in the fossil record at the same location.”
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Dr. Joseph D. Lim, Ed. D., is the former Associate Dean of the College of Dentistry, University of the East; former Dean, College of Dentistry, National University; Past President and Honorary Fellow of the Asian Oral Implant Academy; Honorary Fellow of the Japan College of Oral Implantologists; Honorary Life Member of the Thai Association of Dental Implantology; and Founding Chairman of the Philippine College of Oral Implantologists. For questions on dental health, e-mail jdlim2008@gmail.com or text 0917-8591515.
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Dr. Kenneth Lester Lim, BS-MMG, DDM, MSc-OI, graduated Doctor of Dental Medicine, University of the Philippines, College of Dentistry, Manila, 2011; Bachelor of Science in Marketing Management, De la Salle University, Manila, 2002; and Master of Science (MSc.) in Oral Implantology, Goethe University, Frankfurt, Germany, 2019. He is an Associate Professor; Fellow, International Congress of Oral Implantologists; and Fellow, Philippine College of Oral Implantologists. For questions on dental health, e-mail limdentalcenter@gmail.com/PN
