Modern therian mammals are an active, diverse group characterized in part by upright limbs operating in a parasagittal plane. By bringing ground reaction forces closer to the center of mass, parasagittalism decouples fore- and hindlimb function and enables classically mammalian behaviors such as the selection of asymmetrical gaits and the use of forelimbs in food prehension. Though the adaptive advantages conferred by parasagittalism are clear, the exact route taken by the forelimb to arrive at its present...

Mammals are known for their great range of locomotor behaviors, including unique asymmetric gaits such as galloping and bounding. Asymmetric gaits are made possible by the subdivision of the dorsal vertebral column (the area between the pectoral and pelvic girdles) into two morphologically and functionally distinct regions. Anteriorly, the thoracic region bears ribs and is specialized for respiration, whereas posteriorly the dorsoventrally mobile lumbar region functions in locomotion. Combined, the regionalized dorsal vertebrae allow mammals to breathe and move simultaneously, permitting...