Dr. Susan McIntosh displays the Homo naledi casts which were printed on Rice’s 3D printer merely one year after being discovered.
In October, Dr. Susan McIntosh’s Introduction to Physical Anthropology (ANTH 203) students sent her links to articles about the discovery in South African caves of skulls from a new form of Homo, Homo naledi. While she was already aware of this archaeological discovery, she was excited by her students’ enthusiasm for breaking news related to her course.
Historically, it has taken many years for casts of fossils to be publicly accessible, but archaeologist Lee Burger (University of the Witwatersrand, Johannesburg) has revolutionized a more timely method of disseminating fossil finds: after finding the Homo naledi fossils last year, he used a 3D scanner, translated the information to code, and then placed the files for 90 of the fossils on the Internet for anyone to print with a 3D printer. Although this species was only discovered in September 2014, the 3D files were posted in September 2015 for the public to use. McIntosh read about other scientists printing 3D models of Homo naledi and wondered if it would be possible to do the same at Rice.
Each week, McIntosh does an activity-based class in which she spends about 20 minutes doing an in-class exercise followed by a lecture with questions and student interaction. At the time of this discovery, she was planning to teach a class on the evolution of teeth and the shape of the dental arch in different species of primates and fossil human relatives. She already had casts of skulls for chimpanzees, A. afarensis, A. boisei, and H. habilis. McIntosh wondered if there was a way to obtain Homo naledi casts to add to her activity. Since there was a lot of debate about the identification of the naledi fossils as Homo, a comparison of the teeth would allow students to make their own assessment. She started looking for a 3D printer on campus and discovered that there was a 3D printer housed at OIT’s Primary Data Center. As an outsider to the process, she relied on Dr. George Phillips in the Department of Biochemistry and Cell Biology, to guide her. McIntosh said, “I knew nothing about 3D printing. I downloaded the open source files from the web, took them over on a flash drive to Mudd Lab, and sent the files to Dr. Phillips.”
McIntosh looks over the arsenal of fossil models she has collected to interactively teach her ANTH 203 students about evolution. This year, the activity was further enhanced by the addition of a model from Homo naledi.
With a few days to spare before her class activity, McIntosh received the models of Homo naledi. Students were able to compare the 3D naledi cast of a maxilla (upper jaw) with the maxillae of other species to find the closest match. McIntosh explains, “In this way, students are able to see – without extensive paleoanthropological knowledge – that different species have different sizes and proportions of teeth and differently shaped dental arches. This reveals to them how paleoanthropologists are able to make a species identification based on a fragment of a jaw. ”
While in the past it had taken years from the time of discovery of a species until she was able to display the 3D replicas in her classroom, McIntosh was able to provide the models within a year of its discovery. Students enjoyed the activity, and for McIntosh, “It was exciting to be able to go beyond merely announcing a major new fossil discovery in class by having the students handle casts of the fossils.” In the future, McIntosh plans to continue using this technology to shape her lesson plans and to reveal the latest discoveries to her students.