Qualitative skeletal correlates of wing shape in extant birds (Aves: Neoaves)

摘要: Among living fliers (birds, bats, and insects), birds display relatively high aspect ratios, a dimensionless shape variable that distinguishes long narrow vs. short broad wings. Increasing ratio results in functional tradeoff between low induced drag (efficient cruise) increased wing inertia (difficult takeoff). Given the wide scope of its effects, pattern evolution is an important factor contributes to substantial ecological phylogenetic diversity birds. However, because feathers define wingtip (and hence wingspan ratio) often do not fossilize, resolution avian obscured by missing information. Here I use comparative approach investigate relationship skeletal proxies flight feather attachment shape. An accessory lobe internal index process digit II-1, bony correlate distal primary attachment, shows weak but statistically significant relationships mass independent other morphology. The dorsal phalangeal fossae which house primaries VIII IX, also show trend prominence with higher ratio. Quill knobs on ulna are examined concurrently, consistent signal respect Although quill cited as correlates performance birds, their inconsistent among extant taxa, may reflect diverging selection pressures acting conserved architecture. In contrast, major convergent responses increasing light musculoskeletal integumentary mophology underlies different clades, it unlikely single feature will predictive power across Neoaves. Confident inference basal ornithurine require multiple lines evidence, together understanding clade-specific evolutionary trends within crown.