Little Foot hominin fossil may be new species of human ancestor | Evolution

According to research that raises questions about our evolutionary past, Little Foot, one of the world’s most complete hominin fossils, may be a new type of human ancestor.

Little Foot, introduced to the public in 2017, is the most complete. Australopithecus the skeleton ever found. The foot bones that gave the fossil its name were first discovered in South Africa in 1994, prompting 20 years of painstaking excavation in the Sterkfontein cave system.

Paleoanthropologist Prof. from the University of Witwatersrand, who led the team that excavated the skeleton. Ronald Clarke, attributed to Little Foot to species Australopithecus prometheus. Others believed that Australopithecus africanusA species first described in 1925 and previously found in the same cave system.

Australopithecus – Meaning “southern ape,” the term refers to a group of hominins that existed in Africa 4.2 million years ago.

However, a new study led by Australian researchers has been published. American Journal of Biological AnthropologyHe found that Little Foot’s characteristics differ from both species, which raises a third possibility.

Dr. from La Trobe University in Melbourne, who led the research. “We think this is a previously unknown, unsampled type of human ancestor,” Jesse Martin said.

“It doesn’t look like much Australopithecus prometheus … but it also doesn’t look like all of them African To exit Sterkfontein.

Martin, a postdoctoral research fellow at the University of Cambridge, added: “This thing will be part of the hominin lineage, so it’s possible that it’s not just a point in our human family tree that we haven’t explored before, but a whole branch of that tree.”

Martin said that Clarke was “one of the only people to claim that there were two species of hominins at Sterkfontein” and that in this regard he “was proven right”.

“Where [Clarke] And I’m leaving, claiming it’s definitely not the case Prometheushe said.

Researchers have identified key differences that distinguish Little Foot from others. Australopithecus africanusIncluding a longer nuchal plane (an area at the back of the skull).

“The lower part of the skull is supposed to be pretty preserved in human evolution, so it doesn’t change that quickly,” Martin said. “If you find differences between things at the base of the skull… those differences are more likely to represent different species, because from an evolutionary perspective they don’t change easily. The differences we found are all in that area.”

“Finding evidence of a completely new species hiding in plain sight at Sterkfontain is quite remarkable and counterintuitive,” Martin added, “given that this is the most complete human ancestor fossil on record.”

“We must be able to understand where the human being falls on the family tree.”

The study’s authors did not formally reclassify Little Foot, suggesting: “It is more appropriate for a new species to be named by the research team who have spent more than two decades excavating and analyzing the extraordinary Little Foot specimen. We hope that in this context they will regard our proposal as well-intentioned advice.”

There is also disagreement among scientists about Little Foot’s age. The fossil skeleton was dated as follows: 3.67 million years oldhowever, other scientists have suggested that Little Foot could not be older than that. 2.8 million years.

Prof Ronald Clarke, who discovered the skeleton, has been contacted for comment.