Form and function in the avian pelvis.

The avian pelvis plays a critical role in the hindlimb function of birds, connecting the hindlimb and axial skeleton and serving as the major attachment site for proximal hindlimb musculature. To assess how diversification of locomotor modes in birds has impacted the evolution of avian pelvic morphology, we conducted a two-dimensional geometric morphometric analysis of bird pelves in dorsal and lateral views from 163 species (n = 261) across Aves. We investigated the relationships among pelvic shape and ecology, phylogeny, and allometry, and conducted disparity analyses to understand how pelvic morphospace has been explored through the diversification of Aves.

Absolute abundance and preservation rate of .

Although much can be deduced from fossils alone, estimating abundance and preservation rates of extinct species requires data from living species. Here, we use the relationship between population density and body mass among living species combined with our substantial knowledge of to calculate population variables and preservation rates for postjuvenile We estimate that its abundance at any one time was ~20,000 individuals, that it persisted for ~127,000 generations, and that the total number of that ever lived was ~2.5 billion individuals, with a fossil recovery rate of 1 per ~80 million individuals or 1 per 16,000 individuals where its fossils are most abundant.