Abigail Nishimura

ABIGAIL NISHIMURA, then a graduate student at Stony Brook University, Stony Brook, New York, was awarded a grant in October 2019 to aid research on “Reconstructing Hominin Neck Function Using Experimental and Macroevolutionary Approaches,” supervised by Dr. Gabrielle Russo. Human necks are unusual compared to other living mammals, as we balance our heads above an upright trunk while striding on two legs (bipedalism). Studying the evolution of the mammalian neck is therefore important in understanding the evolution of behaviors that are unique to the human lineage. Here, we used a broad comparative sample and new statistical tests to model patterns of neck evolution in primates, rodents, and marsupials. This project focused on the fifth cervical vertebra through the first thoracic vertebra. Results show that vertebral shape differs depending on a species’ locomotor mode (how a species moves around the environment), substrate (whether a species lives in the trees or on the ground), and to a lesser degree, posture (whether a species has an upright or horizontal trunk). However, evolutionary modeling shows that these differences are subtle in scale and are rapidly adaptable, warranting caution when attempting to infer behaviors from the fossilized necks of mammalian species. Regarding broader impacts, the seven undergraduate trainees who contributed to this project included four women and one member of an underrepresented minority group. Additionally, the hundreds of 3D scans gathered for this project will be uploaded to open-source repositories.