At Least Two Hominin Species Coexisted in Kenya 1.5 Million Years Ago

Paleoanthropologists have discovered 1.5-million-year-old footprints of two completely different species of hominins — Homo erectus and Paranthropus boisei — at a same locality near Lake Turkana in Kenya.

Hominin is a term that describes a subdivision of the larger category known as hominids.

Hominins includes all organisms, extinct and alive, considered to be within the human lineage that emerged after the split from the ancestors of the great apes. This is believed to have occurred about 6 to 7 million years ago.

Paleoanthropologists have long hypothesized that Homo erectus and Paranthropus boisei coexisted.

According to fossil records, Homo erectus persisted for 1 million years more.

Paranthropus boisei, however, went extinct within the next few hundred thousand years. Scientists don’t know why.

Both species possessed upright postures, bipedalism and were highly agile. Little is yet known about how these coexisting species interacted, both culturally and reproductively.

“The footprints are significant, because they fall into the category of trace fossils — which can include footprints, nests and burrows,” said Rutgers University’s Professor Craig Feibel.

“Trace fossils are not part of an organism but offer evidence of behavior. Body fossils, such as bones and teeth, are evidence of past life, but are easily moved by water or a predator.”

Professor Feibel and colleagues discovered the 1.5-million-year-old footprints of Homo erectus and Paranthropus boisei near Lake Turkana in Kenya.

“Their presence on the same surface, made closely together in time, places the two species at the lake margin, using the same habitat,” Professor Feibel.

“While skeletal fossils have long provided the primary evidence for studying human evolution, new data from fossil footprints are revealing fascinating details about the evolution of human anatomy and locomotion, and giving further clues about ancient human behaviors and environments,” said Dr. Kevin Hatala, a researcher at Chatham University.

“Fossil footprints are exciting because they provide vivid snapshots that bring our fossil relatives to life.”

“With these kinds of data, we can see how living individuals, millions of years ago, were moving around their environments and potentially interacting with each other, or even with other animals.”

“That’s something that we can’t really get from bones or stone tools.”

The authors distinguished one set of footprints from another using new methods they recently developed to enable them to conduct a 3D analysis.

“In biological anthropology, we’re always interested in finding new ways to extract behavior from the fossil record, and this is a great example,” said Dr. Rebecca Ferrell, a program director at the National Science Foundation.

“The team used cutting-edge 3D imaging technologies to create an entirely new way to look at footprints, which helps us understand human evolution and the roles of cooperation and competition in shaping our evolutionary journey.”

The findings appear today in the journal Science.

_____

Kevin G. Hatala et al. 2024. Footprint evidence for locomotor diversity and shared habitats among early Pleistocene hominins. Science 386 (6725): 1004-1010; doi: 10.1126/science.ado5275