We have just confirmed that Homo habilis actually existed

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Homo habilis is a paradoxical species. On the one hand, they have a famous name and hold the status of the first members of our family Homo: the first people, if you will. On the other hand, we never really knew that much about them, and what we do know is kind of weird. How can a species be well known and little known at the same time?

We have to start with the name, if only because it’s one of the few things we can be sure of. The species was nicknamed in 1964 by a trio of paleoanthropologists: Louis Leakey, Phillip Tobias, and John Napier. Although, as they acknowledged, it wasn’t their idea – their colleague Raymond Dart suggested “habilis” from the Latin for “capable, skillful, mentally capable, vigorous”.

They applied this name to a collection of bones and teeth they found in the Olduvai/Oldupai Gorge in Tanzania, East Africa. The remains were quite diverse: a lower jaw with teeth, an upper molar, skull bones called parietal bones, and some hand bones. The trio interpreted them as belonging to a single minor.

Crucially, the researchers argued that Homo habilis they were the makers of the Oldowan stone tools found at the site. By saying this, they made the broader claim that tool making is a defining feature of the genus Homo. Less “human” hominins such as Australopithecus probably did not make tools but Homo habilis and their ever-smarter offspring did, and that’s what made them special.

That’s a lot of interpretation to attach to a handful of fossils, but let’s be lenient. Very few hominin fossils were known at the time, and Leakey and his colleagues did what they could with what they had.

Over the next 62 years, researchers found more fossils that they assigned H. habilis. However, other remains have not clarified our understanding of the species. On the contrary, H. habilis he was wasting away

“They call it the trash can taxon,” he says Ian Tattersall at the American Museum of Natural History in New York. “Whenever [researchers] they found something they weren’t quite sure what it was, they just let it go Homo habilis. And pretty soon, Homo habilis became a somewhat unwieldy set of things that you would find very difficult to define.’

So can we understand this essential species and its place in our origins?

A new find

All this has become relevant again, because new H. habilis specimen came to light. It was excavated in 2012 and 2014 from the Koobi Fora Formation in Ileret, Kenya. Researchers led by Frederick Greene at Stony Brook University in New York and Ashley Hammond at the Miquel Crusafont Catalan Paleontological Institute in Barcelona described the remains in Anatomical record on January 13. Grine and Hammond could not speak to me, but Tattersall published comment on the finding January 24th and we spoke on the phone (we were both dealing with the worst connection ever).

The new specimen is the most complete H. habilis sometimes found. It includes the clavicle (clavicle), fragments of the shoulder blade (scapulae), both upper arm bones (humerus), both of the lower arm bones (ulna and radius), and fragments of the base of the spine (sacrum) and hip bone (os coxae).

A lot is still missing: head, ribcage, spine, arms, legs and feet. But it’s enough to find out a lot H. habilis.

This is the most obvious H. habilis he had rather long arms. One of the great trends in human evolution is the shortening of arms: our ape cousins ​​have long arms relative to their legs, while our arms are decidedly shorter. Compared to others Homo species like Homo erectus, H. habilis he had long arms.

For Tattersall, it’s proof H. habilis he still spent a lot of time in trees where long arms are an advantage. Before Homoearlier hominins like Australopithecus They seem to have lived a hybrid lifestyle, spending some time in trees and some time walking on two legs on the ground. “It’s a way of life that has no parallel in today’s world, but it’s obviously been very successful for a long time,” he says. Below Homo species like H. erectus were quite committed to bipedal walking on the ground, H. habilis he still had one foot in the trees.

The skeleton also suggests this H. habilis it was pretty mild. Scientists estimated that the individual was about 160 centimeters tall, but weighed only 30 to 33 kilograms. That’s smaller than most H. erectus specimens, markings again H. habilis as different.

There are still a lot of things we don’t know. We have very little information about diet H. habilis or their social dynamics and group size. It is also not clear how long the species has been around or how widespread it has been.

Yet it seems so H. habilisThe days of being a trash can taxon may be over.

Identity

In his commentary, Tattersall lists the fossils that have been assigned H. habilis over the past six decades. These include a fragmentary skeleton and skull from East Turkana, Kenya, a fragmentary skeleton and palate from Olduvai, another palate from Hadar, Ethiopia, a partial lower jaw from Ledi-Gerar, Ethiopia, and one skull from Sterkfontein, South Africa.

Tattersall calls these fossils “a motley assortment,” and he’s not wrong. There are few of them H. habilis bones of which we have more than one copy, so we cannot be sure that the ones we have are representative.

This led to decades of uncertainty. Some of the alleged H. habilis the fossil may not belong to that species or even to Homo genus. The South African one in particular is widely regarded as Australopithecussuggests H. habilis lived only in East Africa.

Some researchers have even argued that the entire species is a kind of mirage: a collection of bits and pieces from the past. Australopithecus and soon Homolumped together for no good reason.

The new specimen suggests that we can rule out this most extreme possibility and accept most of the alleged specimens. Although incomplete, “it appears to have the basic characteristics of most of the other skeletons that were so-called Homo habilis“, Tattersall says. These isolated fragments and pieces generally match a more complete skeleton.

I’m not saying that it clears everything up. Tattersall says that everything above the neck is still a bit of a mystery: “The skull and the teeth make a rather odd assemblage when you put them together.” Since the new skeleton doesn’t contain anything from the head, it doesn’t help us sort out which ones belong together.

Timeline and scope H. habilis they also need cleaning. “Homo habilis is something that we now know, thanks to the new specimen, to have been around, at least in Tanzania and Kenya, around 1.8 to 2 million years ago,” says Tattersall.

It is possible that this species occurred earlier or later, but this is less clear. The oldest claimed specimen is a partial lower jaw from Ledi-Gerar, Ethiopia, dated to 2.8 million years ago. “In my opinion it is not. Homo habilissays Tattersall Homo than to Australopithecusthat doesn’t mean it necessarily is H. habilishe says. Tattersall suggests that the group that gave rise to Homo was created at that time.

That said, it is an open question whether H. habilis he was indeed the first member Homo genus. It used to look like that Homo erectus (African specimens, which are sometimes called Homo ergaster) appeared later. However, recent fossil finds have moved this species back in time: we now have specimens H. erectus from at least 1.85 million years ago and even 2 million years ago. Combine that with the uncertainties around H. habilis fossil record and it is not clear which species is older.

All of this ultimately means that the origins of our lineage are still something of a mystery. We have fossils that tell us something about it, but we can’t be quite sure what they say. The “simple” story is that the group Australopithecus evolved in H. habilis and some of them later evolved H. erectus (aka H. ergaster). But maybe there were a lot of them Homo species living in parallel, right from the start. Or maybe something else happened.

If that seems a little disappointing, remember: now we know Homo habilis I guess it was real. It was not obvious last year.

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