Data from: Ventilatory mechanics from maniraptoran theropods to extant birds

• Main Authors: Tickle, Peter G., Norell, Mark A., Codd, Jonathan R.
• Format: Dataset
• Language: unknown
• Published: 2012
• Subjects: Life History Evolution; Confuciusornis sanctus; Evolutionary physiology; The Ribs; Alca torda; Branta leucopsis
• Online Access: https://zenodo.org/record/4992528; https://doi.org/10.5061/dryad.cp4tc417

Shared behavioural, morphological and physiological characteristics are indicative of the evolution of extant birds from non-avian maniraptoran dinosaurs. One such shared character is the presence of uncinate processes; respiratory structures in extant birds. Recent research has suggested a respiratory role for these processes found in oviraptorid and dromaeosaurid dinosaurs. By measuring the geometry of fossil rib cage morphology we demonstrate that the mechanical advantage, conferred by uncinate processes, for movements of the ribs in the oviraptorid theropod dinosaur, Citipati osmolskae, basal avialan species Zhongjianornis yangi, Confuciusornis sanctus, and the more derived ornithurine Yixianornis grabaui, is of the same magnitude as found in extant birds. These skeletal characteristics provide further evidence of a flow-through respiratory system in non-avian theropod dinosaurs and basal avialans, and indicate that uncinate processes are a key adaptation facilitating the ventilation of a lung air sac system that diverged earlier than extant birds. Mm. appendicocostales projection angleAngle at which the Mm. appendicocostales projects from the uncinate processes in four extant bird species (Alca torda, Branta leucopsis, Falco tinnunculus and Alectoris rufa). Mm. appendicocostales projection angle.xlsxSMF Av 418Photograph of C. sanctus SMF Av 418 used to calculate mechanical advantage of the uncinate processes for movements of the ribs.mechadv AV418.tifSMF Av 421Photograph of C. sanctus SMF Av 421 used to calculate mechanical advantage of the uncinate processes for movements of the ribs.mechadv AV421.tifSMF Av 419Photograph of C. sanctus SMF Av 419 used to calculate mechanical advantage of the uncinate processes for movements of the ribs.mechadv AV419.tifSMF Av 422Photograph of C. sanctus SMF Av 422 used to calculate mechanical advantage of the uncinate processes for movements of the ribs.mechadv2 AV422.tif