Cataloged as KNM-ER 64061, the partial skeleton is the most total ever credited to Homo habilis

Dating to about 2 million years earlier, the fossil was recuperated from the Upper Burgi Member of the Koobi Fora Formation near Ileret, Kenya.

The specimen was discovered in close association with an almost total set of teeth and jaw pieces, KNM-ER 64060, formerly recognized as coming from Homo habilis

Geological, taphonomic and geochemical analyses show that the teeth and postcranial bones probably originated from the very same person.

Together, the discovers represent what the scientists refer to as ‘potentially the 4th person’ of Homo habilis understood to maintain both diagnostic oral remains and associated postcranial bones, a mix that is extremely unusual in the Early Pleistocene fossil record.

“Indeed, there are just 3 other really fragmentary and insufficient partial skeletons understood for this essential types,” stated Stony Brook University’s Professor Fred Grine.

The KNM-ER 64061 skeleton consists of both humeri, both radii and ulnae, parts of the shoulder girdle, pieces of the hips and sacrum, and other aspects.

No leg bones were recuperated, functions of the hips recommend that lower-limb mechanics were more comparable to later on members of Homo than to earlier australopiths.

At the very same time, the upper limbs inform a more primitive story. The lower arm appears reasonably long compared to the arm, a pattern called a high brachial index, which lines up Homo habilis more carefully with earlier hominins than with Homo erectus

The arm bones likewise have abnormally thick cortical bone, looking like the condition seen in australopiths and other early Homo fossils.

Based upon the length of the humerus, the researchers approximate that the private stood about 1.6 m high.

Approximated body mass, in between about 30.7 and 32.7 kg, is lower than in other recognized Homo habilis specimens and noticeably smaller sized than quotes for Homo erectus

Homo habilis upper limbs have actually been coming a growing number of into focus, and KNM-ER 64061 validates that the arms were relatively long and strong,” stated Dr. Ashley Hammond, a scientist at the American Museum of Natural History, the Institut Català de Paleontologia Miquel Crusafont at the Universitat Autònoma de Barcelona and the Institucio Catalana de Recerca i Estudis Avançats.

“What stays evasive is the lower limb construct and percentages.”

“Going forward, we require lower limb fossils of Homo habiliswhich might even more alter our point of view on this crucial types.”

The findings strengthen the view that Homo habilis kept a mosaic of ancestral and obtained characteristics.

While elements of the skeleton point towards more human-like mobility, the general body percentages and little size recommend that this early types had actually not yet gotten the high, heavier-bodied kind seen in later human beings.

In between about 2.2 and 1.8 million years back, eastern Africa was home to several hominin types, consisting of Paranthropus boisei Homo habilis Homo rudolfensis and perhaps early Homo erectus

The brand-new skeleton highlights that Homo habilis inhabited an unique location amongst them, both physically and evolutionarily.

“Insofar as they are understood, the Homo habilis partial skeletons provide an image of postcranial anatomy that tends to vary from that of other members of our genus, with the caution that the postcranial skeleton of Homo rudolfensis is presently unidentified,” the authors stated.

Their paper was released online on January 13, 2026 in The Anatomical Record

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Frederick E. Grine et alNew partial skeleton of Homo habilis from the upper Burgi Member, Koobi Fora Formation, Ileret, Kenya. The Anatomical Recordreleased online January 13, 2026; doi: 10.1002/ ar.70100