Human-Chimp ancestor was similar to modern african apes

After comparing fossilized shoulder blades, scientists think that the last common ancestor between chimps and humans could have been a modern African ape. And recently published findings say our ancestors stayed up in the trees much longer than we thought.

We split from other apes a very long time ago, so fossils from that time are very rare. In order to test evolutionary hypotheses, a team of scientists compared 3D shape measurements of scapulas of humans, chimpanzees, gorillas, orangutans and gibbons and saw that we have features that clearly link us with African apes.

The image above shows us the scapula of different species. African ape like (top left), modern human (bottom right), predicted ancestral forms (in gray), Australopithecus afarensis (top right), Australopithecus sediba (middle left), Homo ergaster (middle right) and Homo neanderthalensis (bottom middle).

The explanation to this is that we share a common ancestor with these apes, and although we have evolved a lot, modern African apes haven’t. The reason for this to have happened is that humans evolved towards living on the ground while apes continued living in the trees.

https://www.ucsf.edu/news/2015/09/131526/shouldering-burden-evolution

Ancient neanderthal skulls reveal insights into human evolution

Not long ago, 17 skulls have been found in a Middle Pleistocene cave in Spain. Some show some Neanderthal features and other more primitive ones, and this suggests that Neanderthals didn’t evolve these defining characteristics all at once but in stages. In fact, despite having some Neanderthal features, some of the findings had small brain cases, while Neanderthals could even have brain cases bigger than humans.

These fossils have some features in common with Neanderthals but are too primitive to be Neanderthals but too young to be some primitive human ancestors so specialists conclude that these fossils are the oldest reliably dated proto-Neanderthals.

The Neanderthal features they had were related to chewing. Modifications were made due to the intensive use of the frontal teeth, often used as a “third hand”, used to grip objects like meat, so they could have free hands to steady the object and cut it with a tool.

The findings suggest a mosaic pattern of evolution, with different traits evolving separately at different rates, making Neanderthalization more like a build-up rather than a linear evolution.

For more further information, check:

http://www.eurekalert.org/pub_releases/2014-06/aaft-swm061314.php 

http://news.nationalgeographic.com/news/2014/06/140619-neanderthal-spain-skulls-bones-pit-science-heidelbergensis/#

Orrorin tugenensis and the unclear origin of bidepalism

Nowadays, we all know that our ancestors began to diverge from the other arboreal neighbors, by developing bipedality which become a great advantage. But analysis carried out in 2013 suggests that bipedality could appear before Australophitecus afarensis. The discovery of a 6 million year old femur carried out by Sergio Almécija and his group of researchers from Stony Brook University in 2000, suggest that bidepality could appear before Lucy, which means 2 million years before.

The bones of these individual belong to the species Orrorin tugenensis, that lived approximately 6 million years ago at the end of the Miocene in eastern Africa (Tugen Hills, central Kenia). To analyze the bone, it was subjected to cutting-edge technology that analyses the 3D morphology. The obtained information was compared with a variety of apes and other hominids, and they concluded that the femur has an intermediate morphology between fully bipedal primates and those that were arboreal or quatrupedal. One comparison was with Australopithecus afarensis (Lucy) and determined that Orrorin´s femur and humerus are about 1,5 times larger.

Although some scientist and researchers do not agree Orrorin tugenensis was a truly hominin, it was likely one of the very first, and this new information brings new hypotheses about how bipedality could have been originated.

For the moment, there is no enough evidence to determine if this individual was the first to develop bidepality, and further study of other ape from the Miocene will be needed, in order to better understand where and when bipedality originated.

For more further information: http://www.newswise.com/articles/early-tree-dwelling-bipedal-human-ancestor-was-similar-to-ancient-apes-and-lucy-but-not-living-apes