44-11 Ecometric Investigation of Artiodactyl Locomotion in Miocene Assemblages from the Great Plains

Session: Paleontology, Paleoecology/Taphonomy, Phylogenic Morphological Patterns (Posters)

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Abstract:

The Miocene (~20-5 .3 Ma) was a period of change for North American environments. Interconnected forests were replaced by patchy landscapes of woodlands and grasslands, which contributed to the diversification of animals adapted to open-canopy habitats, such as many artiodactyls (even-toed, hoofed mammals). Many groups developed cursorial morphology that allowed efficient movement over long distances. A positive relationship between habitat openness and cursoriality has been documented in modern taxa within the astragalus, or ankle bone. This load-bearing bone element scales with body mass and exhibits a functional ratio that correlates with habitat. Communities with low ratios are associated with greater cursoriality in open-canopy habitats while high ratios are exhibited by communities from closed-canopy habitats. Results from Miocene communities in the topographically complex Mojave Region suggest that a phylogenetic overprint may complicate interpretation, so we collected data from the more topographically uniform Great Plains to evaluate the strength of this relationship. We measured 145 astragali from Montana and Nebraska in the vertebrate collections of the Carnegie Museum of Natural History. This study investigates four families: Antilocapridae, Camelidae, Entelodontidae, and Merycoidodontidae. By analyzing the locomotor morphology of artiodactyls from the Miocene Great Plains, we gain a better understanding of environmental conditions and their effect on mammalian evolution. Our dataset allows us to test three hypotheses: 1) Do artiodactyls in the Great Plains exhibit lower functional ratios than those in the Mojave? 2) What is the distribution of body mass among the sampled localities? 3) Do phylogenetic signals suggest that lineage plays a stronger role than environment in the evolution of cursorial morphology? We will also evaluate the relationship between body size, lineage, and functional ratio to determine which variables exert the strongest influence on the evolution of locomotion in artiodactyls.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2, 2026

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