Characterizing the Aquatic Locomotor Evolution of Archaeocetes Utilizing Post-Cranial Geometric Morphometrics



Levy, Andrew Evan

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Cetaceans are one of the most unusual and divergent forms of mammals in terms of both their morphology and ecology (Uhen, 2010). Numerous methods have been used to characterize the locomotion and locomotor evolution of cetaceans, from comparing fossil morphology to modern mammalian analogues (Thewissen and Fish, 1997) to observing the microstructure and osteology of archaeocete postcrania (Houssaye et al., 2015). I used three-dimensional landmark-based geometric morphometrics to analyze and compare the shape of archaeocete innominata and to investigate the controls on their morphology. While I had hypothesized that the shape of the innominate was primarily driven by aquatic locomotory mode, my results indicated that neither locomotory mode, nor the secondary factors of phylogenetic affinity and robustness fully explained the shape variability. This suggests that more of the postcranial skeleton, such as the hindlimb and vertebral column, must be looked at in conjunction to comprehend the drivers of innominate shape change.



Locomotion, Paleontology, Cetacean, Morphology, Archaeocete, Morphometric