Meeting Abstract

P2.74  Wednesday, Jan. 5  Whole bone and cross-sectional morphology of the wing skeleton in procellariiform seabirds: implications for differences in flight behavior SIMONS, Erin L. R.*; O’CONNOR, Patrick M.; Midwestern Univ. esimon@midwestern.edu

Procellariiforms are wide-ranging pelagic seabirds that span a large body size range, exhibit high wing size and shape variability, and employ a variety of flight behaviors (i.e., flap-gliding, dynamic soaring, and underwater flapping). The objectives of this study were to characterize the external whole bone and cross-sectional morphology of the wing skeleton, examine the relationship between morphology and flight mode, and to compare and integrate these results with previous research on other birds. External length and diameter measurements of wing elements were taken on 530 skeletal specimens from 101 species of procellariiforms. In addition, the main wing elements of 17 of the species were microCT scanned to examine the cross-sectional geometry. The lengths of all three main wing elements were found to be positively allometric when phylogenetic relationships were taken into account. In addition, principle components analysis (PCA) and classification and regression tree (CART) analysis found that the diameters of distal elements and lengths of proximal elements were able to successfully partition procellariiform species into primary flight mode groups. Analysis of cross-sectional geometry indicates that the elements of birds that utilize more high frequency flapping exhibit more elliptically shaped cross sections of the distal elements, a shape optimized to resist bending loads. The cross sections of elements of dynamic soaring birds exhibit large polar moments, or shapes optimized to resist torsional loads. These results are congruent with results observed in other bird groups, namely pelecaniforms, and therefore may indicate general trends in the structure and function of the avian wing skeleton.