New species discovered

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University of Indianapolis alumnus Zachary Throckmorton returned to campus to share his research and findings on an entirely new species of Homo genus.  His talk covered the findings of the international research team he was a part of in 2014.

Throckmorton completed his undergraduate studies with a bachelor of science degree in anthropology-zoology at the University of Michigan, Ann Arbor, in 2004 before coming to the University of Indianapolis where he earned his master’s of science degree in human biology in 2007. In 2009, he completed his masters’ of science degree in anthropology at the University of Wisconsin-Madison, followed by his advance to dissertator status in 2010. Under the direction of  John Hawks, he earned his Ph.D. in May of 2013 and is currently a professor at Lincoln Memorial University.

In 2013, Homo naledi was discovered by paleoanthropologist Lee Berger in the Cradle of Life region of South Africa in Rising Star Cave. The cave posed a challenge for excavators because its passageways were too small for average cavers. In turn, an all-female team of small and talented cavers navigated the passageways to where Homo naledi lay. When they arrived at the base, they discovered a trove of more than 1,500 fossils and fossil fragments, belonging to at least 15 separate skeletons, one of the richest collections of hominin fossils ever discovered.

In January 2014, just as he had to find his team of cavers, Berger put out an ad on Facebook that called for early career-scientists—defined as “advanced graduate students who were all but dissertation”—and untenured assistant professors.

“Basically, [these were] people who were about to, or who had just earned their Ph.D.’s,” Throckmorton said. “They were looking for people who had expertise in a specific, particular area in the human body and in paleoanthropology.”

Throckmorton’s area of expertise is the anatomical variation and evolution of the human foot and ankle, and his body of work was deemed valuable, leading to his selection. He was made aware of his selection for the team in March of 2014 and spent six weeks with a group of about 25 others in the workshop in May and June of 2014.

In his presentation, Throckmorton brought to light the numerous similarities, differences and oddities of Homo naledi. He began by examining the skull, which was very similar in structure to  that of modern humans. The biggest difference is that the fossils had a brain less than half of the size of modern humans. The size and makeup of the teeth suggested further that the fossils belonged to the genus Homo.

Throckmorton then examined the shoulder, which he noted was much more ape-like and designed for climbing than a traditional human shoulder. The hands, however, consisted of long slender digits with distinct thumbs and curved fingers, suggesting they would have been able to use tools. The curvature of the fingers was also a climbing adaptation.

The part of the body with the least number of well-preserved fossils was the chest and abdomen. According to Throckmorton, when the body decomposes, it releases different substances from that section of the body, causing it to erode and break down bones in the region. From digital reconstructions and data from the rest of the body, researchers were able to deduce that Homo naledi was only about 100 pounds and stood only about five feet tall.

Throckmorton’s area of expertise, the foot, revealed much about the early hominins. Most importantly, the structure is strikingly similar to that of modern humans, the main difference being that the foot is flatter and has more curved toes. The foot and leg structures suggest that Homo naledi was built to walk upright and had a similar range of motion to that of modern humans.

Sophomore anthropology and archaeology major Jessica Thompson attended the event because the findings pertain directly to her field of study. Thompson said that she would love to have an opportunity such as Throckmorton’s.

“It would be awesome to go out and be able to do digs like that, but I can’t have my hopes up too much,”  she said. “I’m just planning on trying to work in a museum to do curation or historical preservation in the natural history section.”

Throckmorton, before his opportunity with Homo naledi, expressed a similar sentiment towards being a part of a discovery of this magnitude.

“I never had the audacity—in my wildest dreams—that I would have an opportunity like this,” he said. “In fact, I designed my research career assuming that I would never have early access to hominin fossils.”

Zachary Throckmorton can be followed on Twitter @throckman for his latest updates.

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