Human evolution; another Australopithecus species? (Introduction)

by David Turell @, Friday, December 07, 2018, 01:45 (10 days ago) @ David Turell

Still under debate about it, but sure looks like it:

https://www.newscientist.com/article/2187639-exclusive-controversial-skeleton-may-be-a-...

More than twenty years after it was first discovered, an analysis of a remarkable skeleton discovered in South Africa has finally been published – and the specimen suggests we may need to add a new species to the family tree of early human ancestors.

"The analysis also found evidence that the species was evolving to become better at striding on two legs, helping us to understand when our lineage first became bipedal.

"The specimen, nicknamed “Little Foot”, is a type of Australopithecus, the group of hominins to which the famous fossil “Lucy” belonged. Lucy’s species is called A. afarensis, but we know of several other species of these human-like primates living in Africa around 2 million years ago, including A. africanus.

***
"The Little Foot fossil came to light in the 1990s. Ronald Clarke of the University of the Witwatersrand in Johannesburg, South Africa was asked to go through a collection of bones from Sterkfontein Cave in South Africa. In 1994 he found that four foot bones, thought to belong to monkeys, actually resembled existing fossils belonging to the Australopithecus group.

"The foot bones were quite small, prompting Clarke’s now-deceased colleague Phillip Tobias to dub them “Little Foot”, in reference to the Bigfoot hominin that some believe roams North America.

"In 1997, Clarke and two colleagues found more of the skeleton encased in rock within the same cave. He began excavating it, a process that continued for over a decade. Because the fossilised bone flaked easily, Clarke chose to painstakingly remove the bones from the rock using only an air scribe – a tool that shoots out a thin jet of pressurised air.

***

"The result is a virtually complete skeleton that promises to tell us much about early human-like primates.

A flurry of initial studies, published at last, reveal that Little Foot was an elderly female, about 130 centimetres in height.

"According to a study led by Travis Pickering of the University of Wisconsin-Madison, Little Foot had an arm injury. He suspects she fell onto an outstretched hand during her youth, and that the resulting injury troubled her throughout her life.

"Robin Crompton of the University of Liverpool, UK and his colleagues have analysed how she would have walked. He says it is the first fossil of this age ever to have been discovered with its limbs fully intact.

“'This hominin had longer lower limbs than upper limbs, like ourselves,” says Crompton. This is an interesting finding, as the slightly older hominin Ardipithecus, which came before Australopithecus, had longer arms than legs – more like great apes do. “That means it was being selected for stride length in bipedalism,” says Crompton.

"Little Foot would not have been as good at carrying objects as we are. However, she would have been better at climbing trees than modern humans.

"That would have suited her home: a mix of tropical rainforest, broken woodland and grassland, through which she roamed widely.

A further paper examines the deposits in which Little Foot was encased and concludes that the fossil is 3.67 million years old, more than a million years older than previously thought. (my bold)

"Clarke has argued for over a decade that Little Foot does not belong to any of the known Australopithecus species, and should be named a new species in its own right. He favours calling it A. prometheus.

"The name was coined in 1948 by Raymond Dart, to describe a piece of skull found at Makapansgat in South Africa. Dart is a key figure in anthropology, because in 1925 he described the first Australopithecus specimen, the Taung Child. He used the fossil to argue that humans evolved in Africa. At the time most biologists thought our origins lay in Asia, and Dart was ridiculed for years until other discoveries confirmed that he was right.

"Clarke is convinced that many of the bones from Sterkfontein, including Little Foot, are not A. africanus, so he has resurrected the name A. prometheus. “There are many, many differences, not only in the skull but also in the rest of the skeleton,” he says. They include a flatter face than A. africanus, and larger teeth with a big gap between the upper canines and incisors.

"There is also Little Foot’s diet. Based on her teeth, she ate almost nothing but plants. “A. africanus was more omnivorous,” says Clarke."

Comment: The main thrust here to recognize is that this lady is roughly Lucy's age in fossil time, but she has longer arms than legs and Lucy is longer arms. What this means is a that there were several lines of hominin development going on at different places in Africa in the same periods of time. Places of discovery, to remind us, Lucy is Northeastern Africa and Little Foot is South Africa. It suggests God liked diversity in evolving humans, just as He created diversity in the huge bush of like. I suspect the reason for the diversity in life is econiches for food, while I suspect He already knew what H' sapiens would be like when evolution got to that point..


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