Adaptation and constraint in the evolution of the mammalian backbone

摘要: The axial skeleton consists of repeating units (vertebrae) that are integrated through their development and evolution. Unlike most tetrapods, vertebrae in the mammalian trunk subdivided into distinct thoracic lumbar modules, resulting a system is constrained terms count but highly variable morphology. This study asks how thoracolumbar regionalization has impacted adaptation evolvability across mammals. Using geometric morphometrics, we examine evolutionary patterns five vertebral positions from diverse mammal species encompassing broad range locomotor ecologies. We quantitatively compare effects phylogenetic allometric constraints, ecological between regions, impact on (disparity rate) serially-homologous vertebrae. Although signal allometry evident throughout trunk, effect ecology partitioned positions. Lumbar shape correlates strongly with ecology, differentiating taxa based use asymmetric gaits. Similarly, disparity rates also elevated posteriorly, indicating link region, adaptation, evolvability. Vertebral mammals facilitated rapid evolution posterior response to selection for locomotion static body support.