Meeting Abstract
Birds possess unique modifications of the tetrapod Bauplan, including pneumatization of the postcranial skeleton that results from invasion of bone by respiratory epithelium. The degree of pneumaticity in living birds varies greatly among taxa. Previous research has characterized the degree of pneumaticity in selected Avian groups and proposed evolutionary hypotheses, frequently related to body size and/or ecological drivers, in which this variability is framed. This study focuses on Cuculidae, a heretofore unsampled clade that occupies an early branching position in Neognathae and exhibits a broad distribution of body sizes, geographic ranges and types of habitat occupied. Sixteen species were sampled, capturing much of the aforementioned diversity and representing all major cuclid subclades. Skeletal specimens from museum collections were examined for osteological correlates of pneumaticity, with anatomical regions for each specimen scored based on the presence/absence of pneumatic features. This survey reveals both phylogenetic and ecological signals. In both Crotophaginae and Neomorphinae, the basic pneumaticity condition includes aeration of the sternum, humerus, femur, pelvic girdle, dorsal ribs and entire vertebral column except C1. In Cuculinae, Couinae and Centropodinae, the same patterns exist with the exception of the femur. The femur has the greatest variability across Cuculidae, with slightly more than half the specimens sampled exhibiting a pneumatic femur. Other variable regions include bones of the pectoral girdle and the tibiotarsus. In addition to a phylogenetic signal, there appears to be a relationship between relative pneumaticity and both body size and preferred habitat (e.g. terrestrial vs. arboreal).
