DMU Anatomy Faculty Attend Pivotal Symposium on Human Ancestor

Heather Garvin, Ph.D., and Caroline VanSickle, Ph.D., both faculty members in the Department of Anatomy at Des Moines University Medicine and Health Sciences, were recently invited to participate in a special symposium celebrating a decade of study of the fossils of the human relative, Homo naledi. Entitled "Societies, Culture and Behavior - The Next 10 Years of Homo naledi Studies," the symposium, sponsored by the John Templeton Foundation and supported by the National Geographic Rising Star Project, sought to develop the future of anatomical and cultural research of this fossil species.

Garvin, a forensic anthropologist, and VanSickle, a paleoanthropologist, first joined the Rising Star Project in 2014 alongside scientists from America, Europe, Africa and Asia. Together, this distinguished team of scientists evaluated over 1,550 fossil bone fragments that had been discovered in the Rising Star Cave System of South Africa the year prior. Their work resulted in the introduction of a new human ancestor - Homo naledi. This species lived around 300,000 years ago and had skeletons adapted to both climbing and walking on two legs, with a brain one-third the size of humans today. There is much debate about how more than 20 Homo naledi individuals ended up deep in the cave system, raising questions about their potential use of fire and tools and what it could mean if this species was deliberately placing their dead in this difficult-to-navigate cave system.

Heather Garvin, Ph.D., left and Caroline VanSickle, Ph.D., right at the Rising Star cave where Homo naledi fossils were found.

Both Garvin and VanSickle have continued work on Homo naledi since they joined DMU in 2017 and 2023, respectively.

With extensive experience in modern human data, Garvin published the first three-dimensional reconstruction of the skull and led the team that estimated the brain and body size of the Homo naledi species.

"Part of the process in understanding Homo naledi is comparing the fossils to modern humans and extant apes. We estimated the brain and body size because the evolution of both is heavily referenced when deciding if something belongs to our genus, Homo," Garvin says.

Meanwhile, VanSickle published the initial descriptions of the fragmentary pelvic remains of this species and analyzed how its pelvis changed during growth and development.

"The anatomy of a fossil pelvis can tell us how the species walked and gave birth," VanSickle says. "The difficulty with Homo naledi is that we have a lot of fragments from multiple individuals, so we first must determine which pieces are from the same individual. It's like doing a difficult puzzle with no image to guide you."

During the 10-year reunion symposium, participants discussed strategies for ongoing studies of Homo naledi. They visited the Rising Star Cave System and other fossil sites in the area to see how the excavation infrastructure has expanded since 2014.

"The symposium united those of us who have worked on the fossils from the beginning with those currently excavating the sites," VanSickle says. "This allowed us to learn more about each other and the part we continue to play in learning about this early ancestor, something that is difficult to do over email." Garvin added that "the symposium also brought together an interdisciplinary group of scientists, providing unique perspectives to research questions."

Lee R. Berger, head paleoanthropologist on the Rising Star Project, has prioritized public outreach and open-access science since the beginning of the project. During the symposium, he spoke about the challenges of maintaining those values at sites where fossils are found faster and at a larger quantity than they have been in the past.

"Fossils are being discovered more frequently than they were in the past, which can make it difficult for scientists to keep up," VanSickle says. "One of the goals we discussed at the symposium was how to increase the involvement of South African scientists from excavation to publishing."

Garvin, VanSickle and other researchers continue to study the fossils in light of new information to better analyze how this species lived.

"As more fossils are discovered, it provides additional pieces of the puzzle, not only to who Homo naledi was, but also how our own species evolved," Garvin notes. Garvin and VanSickle are excited to be a continued part of the project. Updates will be shared as new research is published.

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