We are so excited to announce Dr. Wilken’s successful defense of his thesis, entitled “The Load Paths in the Jaws of Extant Mammals and Fossil Mammaliaforms and Their Significance for Mammal Jaw and Ear Evolution”. We wish him luck as he moves on to his new job at the University of Missouri!
Congratulations to Alec Wilken and Chelsie Snipes for publishing their new paper, “Biomechanics of the mandibular middle ear of the cynodont Thrinaxodon and the evolution of mammal hearing”, along with Dr. Ross and frequent collaborator Zhe-Xi Luo! This paper uses finite element analysis to show that the 250-million-year-old synapsid Thrinaxodon already possessed tympanic hearing similar to modern mammals, relying primarily on a soft-tissue eardrum for airborne sound detection. The results indicate that the functional shift toward a mammalian middle ear—detached from the jaw and specialized for sensitive hearing—occurred very early in mammalian evolutionary history. This paper was covered in UChicago’s Biological Sciences Division newsletter- see the coverage here!
Congratulations to Kaleb Sellers, former Ross Lab postdoctoral scholar, for his new position in the Oral Biology department at the University of Illinois: Chicago, where he is now a Clinical Assistant Professor! We are thrilled to continue to have Kaleb nearby, and hope to continue spending time with him and collaborating on projects.
Congratulations to Dr. Kaleb Sellers, Alec Wilken, and their colleagues at the University of Missouri on the publication of their new paper, “Quadrate orientation and joint reaction force underwent correlated evolution during suchian evolution”, in the Journal of Anatomy! Using 3D biomechanical modeling of fossils and living crocodylians, the authors show that the orientation of the quadrate bone in the jaw closely matches the orientation of joint reaction forces (JRF) in the sagittal plane. These findings demonstrate that quadrate anatomy evolved in coordination with JRF during suchian evolution, providing a quantitative framework for studying evolutionary changes in jaw joint biomechanics.
Congratulations to Dr. Peishu Li and his collaborators within and outside the Ross Lab (including two undergraduate students and one high schooler working with the lab) for publishing a new paper in Integrative and Comparative Biology. The paper compares and contrasts mechanisms of tongue base retraction in macaques, opossums, and dogs to investigate hypotheses of their evolutionary conservation, concluding that the the biomechanics of TBR are functionally diverse and not strictly determined by anatomical variation, allowing for evolutionary flexibility in hyolingual morphology without compromising swallowing performance.
Congratulations to Ross Lab postdoc, Yeganeh Sekhavati, for publishing a new paper in the Journal of Human Evolution! The paper examines the evolution of foot morphology in hominins, focusing on changes essential for bipedalism. Dr. Sekhavati and colleagues analyzed 62 foot-related traits and reconstructed ancestral characteristics to trace foot evolution from the last common ancestor of Homo and Pan. The results suggest a Pan-like ancestor, with early adaptations for foot eversion and midtarsal stability preceding other stability features. Additionally, arboreal traits were found in the Paranthropus and Australopithecus clades, indicating evolutionary adaptations from an African ape-like ancestor.
Dr. Ross has published 2 new papers in April. The first, coauthored with lab alum Dr. Amanda Smith, along with many other collaborators, finds that Homo habilis, while exhibiting australopith-like facial strain during biting, was not adapted for forceful molar processing, suggesting that dietary or food processing changes were significant in the emergence of Homo. The second, with Ross Lab alum Dr. Katie Whitlow and UChicago researcher Dr. Mark Westneat, finds that that bowfin, similar to teleost fishes, adapt their jaw movements, hyoid arch depression, and pectoral girdle motions based on prey type and suggests that the ability to modulate feeding strikes evolved early in actinopterygian fishes and may be an ancestral trait for jawed vertebrates.
