Homo naledi and 3D printing

Contributed by Ryan Wheeler

Since the announcement of Homo naledi’s discovery in 2015, this South African fossil hominin has made an appearance in the multidisciplinary science course Human Origins, taught at the Peabody and offered as a senior science elective by Phillips Academy.

Over 100 specimens of Homo naledi have been scanned and made available via Duke University’s MorphoSource website. This represents unprecedented access to the fossils. Typically, we rely on older casts (our plaster casts from Wenner-Gren’s twentieth century casting program have become quite fragile!) or models made from photos and measurements.

Image of Homo naledi hand from Morphosource website.
Reconstruction of Homo naledi hand from MorphoSource website.

Last year in Human Origins Phillips Academy Mkerspace guru Claudia Wessner helped us 3D print Homo naledi’s femur, which includes some unusual features, including a distinct sulcus or furrow on the femoral neck that is not known in other hominins. Students and instructor alike puzzled over the femur, and compared it to other casts and models in the Peabody collection.

This year Ms. Wessner was kind enough to host us again and discuss different types of 3D scanning and printing and help us think how these might be useful in paleoanthropology and physical anthropology.

Image of students and Makerspace guru Claudia Wessner with 3D print of Homo naledi hand.
Human Origins students look on as Claudia Wessner prepares the resin print of Homo naledi’s hand for a bath in alcohol.

Instead of the femur, we chose to do a 3D print of Homo naledi’s hand, also available via the MorphoSource website. We were treated to side by side 3D prints using the Makerspace’s filament and resin printers. While the prints with the filament printer were interesting, the resin print is at a level comparable with a cast or model, in terms of finish and detail. Lee Berger and his colleagues, involved in discovery and study of Homo naledi, have pointed out that the hand is quite similar to that of a modern human, but also has curved bones likely related to tree climbing. Students in Human Origins 2017 got a chance to see Homo naledi’s hand up close and compare with bones of a modern human, noting the similarities and differences.

Image of resin 3D hand print.
Resin 3D hand print.

In the intervening months between the 2016 and 2017 Human Origins classes we’ve learned a lot more about Homo naledi. Lee Berger’s book, Almost Human, was published, adding lots of exciting details to the discovery and quest to date the remains, and perhaps most important, we now understand the dating of the fossils. In May 2017 we learned that Homo naledi dates between 236,000 and 335,000 years ago, making them a cousin, rather than great-grandparent of modern humans. It is fascinating to imagine, however, that a hominin that combined aspects of Australopithecines and much more modern features existed around the same time as the earliest anatomically modern humans.

Image with comparison of four hands: from upper left, clockwise: 3D resin print of Homo naledi; plastic anatomical model, modern human; 3D filament print, Homo naledi; real bone anatomical model, modern human.
Comparison of hands, from upper left, clockwise: 3D resin print of Homo naledi; plastic anatomical model, modern human; 3D filament print, Homo naledi; real bone anatomical model, modern human.

An end of the term assignment, Human Origins in the News, asks students to find recent and relevant news stories and share them with the class. One story—from September 2017—reports on new fossils found at the Rising Star Cave system. Also members of the new genus and species, these fossils may help understand how Homo naledi accessed the cave and if they were being interred there.

Beyond the classroom, Homo naledi inspired some excitement in one of the seniors who took the course in 2016. I was delighted when she wrote to me in May 2017 to report that Lee Berger’s Almost Human book was out–she had pre-ordered on Amazon and her copy had arrived. A few months later she had a chance to hear Dr Berger deliver a lecture on Homo naledi at the Chautauqua Institute in New York.

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