Home LATEST NEWS Issa climbed like a monkey and walked like a human

Issa climbed like a monkey and walked like a human

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The new lumbar vertebrae discovered […] form one of the most complete lower backs ever discovered in early hominids and provide insight into how this ancient human relative walked and climbed, explains the University of the Witwatersrand in a press release.

Silhouette of Australopithecus sediba showing the newly discovered vertebrae. View larger imageHave (New window)Have

Silhouette of Australopithecus sediba showing newly discovered vertebrae along with other skeletal bones of the species.

Photo: NYU / WITS UNIVERSITY

Paleontologists from 17 establishments participated in the work published in the journal eLifeHave (New window)Have (in English) which describe the new fossils. These vertebrae constitute, according to scientists, the missing link which settles an old debate on the mode of locomotion of this ancient species.

These fossils were discovered in 2015, during excavations taking place at the Malapa fossil site, located in South Africa in the area of ​​the sites of the Cradle of Mankind, listed as World Heritage of Humanity.

It was on this site that paleontologist Lee Berger of the University of the Witwatersrand discovered the first remains of a Australopithecus sediba in 2008, which he described in an article published in 2010.

The new vertebrae were recovered from breccias, conglomerates of rocks resulting from the mechanical degradation of other rocks.

The lumbar region is key to understanding the nature of bipedalism in our earliest ancestors and to how well they were adapted to walking on two legs., explained in the press release Professor Scott Williams of the University of the Witwatersrand, the main author of the article.

Reconstruction of the appearance of an Australopithecus sediba.View larger imageHave (New window)Have

Reconstruction of Issa’s appearance on display at the University of Michigan Museum of Natural History.

Photo: University of Michigan Museum of Natural History / Elisabeth Daynès / S. Entressangle

Lumbar vertebrae series are extraordinarily rare in the hominid fossil record, and only three comparable lower spines are known throughout the early African record., continues the scientist.

The female skeleton bears the catalog number MH 2, but researchers have dubbed it Issa, which means protective in Swahili.

This discovery also established that, like humans, Australopithecus sediba only had five lumbar vertebrae. Issa is one of only two primitive hominid skeletons to have both a lower spine and relatively complete dentition..

These vertebrae virtually complete her lower back and make Issa’s lumbar region the best-preserved ever to be discovered.said Lee Berger, who is one of the study’s authors and the leader of the Malapa Project.

Previous analyzes of the species’ incomplete lower spine, performed by authors not involved in the present study, supported the hypothesis that the spine of sediba was relatively straight, without curvature, or lordosis, typically seen in modern humans and associated with bipedalism.

In addition, these analyzes suggested that the spine of the Australopithecus sediba more like that of extinct Neanderthals and other more primitive species of ancient hominins.

However, the recent discovery reveals that Issa’s lordosis was in factHomo erectus) from Kenya, 1.6 years oldmillion years ago, and some modern humans “,” text “:” more extreme than that of any other Australopithecus discovered to date, and that the magnitude of the column curvature observed was only exceeded by that observed on the spine of the Turkana man (Homo erectus) of Kenya, 1.6 million years old, and some modern humans “}}”>more extreme than that of all other Australopithecines discovered to date, and that the magnitude of the spinal curvature observed was only exceeded by that observed on the spine of Turkana man (Homo erectus) from Kenya, 1.6 million years old, and some modern humans.

While the presence of lordosis and other features represents an obvious adaptation to two-legged walking, other features suggest strong trunk musculature, possibly associated with arboreal behaviors.says Prof. Gabrielle Russo of Stony Brook University, who also participated in the study.

Strong transverse spines pointing upwards are usually indicative of a strong trunk musculature, as seen in great apes, adds Prof. Shahed Nalla, from the University of the Witwatersrand. Together with other parts of the torso anatomy, this indicates that the sediba has retained clear adaptations for climbing.

Other work carried out on this ancient species has shown mixed adaptations of its skeleton, which tends to show its transient nature between walking like a human and adaptations to climbing. These include the distinctive features of the upper and lower limbs, but also the pelvis.

The spine connects it all, concludes Professor Cody Prang of Texas A&M University.

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