The Howl of Rancho La Brea: the functional morphology of Pleistocene canid hyoids

Abstract

The Rancho La Brea (RLB) fossils housed at the La Brea Tar Pits and Museum in Los Angeles, California represent one of the richest collections of carnivoran fossils in the world. The collection is particularly well known for exceptional preservation, including that of of rare and understudied bones. Among these, the RLB collection houses hyoids from several extinct species, including relatively large samples of specimens from the dire wolf (Canis dirus) and the coyote (Canis latrans). In this study, we compare fossilized hyoid elements from these two fossil samples to modern specimens: the gray wolf (C. lupus), red wolf (C. rufus), and modern coyote (C. latrans). Seven measurements were taken on each long bone of the hyoid apparatus and eight measurements of the u‐shaped basihyoid. Principal component analysis was performed to determine statistical differences between species and the drivers of those morphological differences. For most of the bones, the majority of the variation was driven by size. Red wolves, modern coyotes, and RLB coyotes could not be differentiated from each other based on any of the hyoid elements, but dire wolves could be clearly differentiated from all other canids for all elements. The hyoid apparatus of C. dirus is larger and more robust than that of C. lupus, its closest modern analogue. As larger hyoids have been associated with a lower vocal frequency, this distinction would likely result in the vocalizations of C. dirus occurring at a lower frequency than those produced by C. lupus. Support or Funding Information North Carolina State University Office of Undergraduate Research Grant