PhD: Evolution and ecomorphology of the avian skeleton

Birds comprise over 10,000 extant species that diverged from their last common ancestor in the Late Cretaceous. The extant avian radiation exhibits striking locomotor disparity, including highly varied modes of flight, as well as subaqueous diving, and flightlessness, and some of this variation is evident among the earliest fossil birds. Flight in particular is of central importance to understanding the evolutionary success of birds. Its origin is thought to have resulted an in energetic trade-off between development of the fore- and hind-limbs (Heers & Dial 2015), and exposed bone-related portions of the genome to strong selection (Machado et al. 2016).
Many hypotheses have been proposed to describe how the morphology of the avian skeleton has responded to evolutionary variation in locomotory function (Videler 2005). These hypotheses advance our understanding of ecomorphological adaptation and the mechanics of flight, as well as terrestrial locomotion in birds. Furthermore, they provide a tool with which to infer the locomotory capabilities of extinct species, and can shed light on the evolutionary origin of flight from non-flying dinosaur ancestors (Xu et al. 2014). However, relationships between skeletal morphology and locomotion across the evolutionary history of living birds are poorly constrained, limiting our ability to defend these inferences.
This project will apply quantitative methods, including 3D geometric morphometrics and phylogenetic comparative methods, to address this knowledge gap. Substantial data for this research are available in the form of a database of CT scans of the skeletons of more than 400 bird species documenting multiple independent origins of many locomotory styles including flightlessness, swimming and soaring. By quantifying skeletal form across this broad taxonomic sample, the student will test key hypotheses regarding the evolution of the avian skeleton, form-function relationships, and their significance for our knowledge of early birds and the dinosaur-bird transition.

References
Videler. 2005. Avian flight. Oxford University Press.
Heers & Dial. 2015. Wings versus legs in the avian bauplan: development and evolution of alternative locomotor strategies. Evolution 69, 305–320.
Machado et al. 2016. Bone-associated gene evolution and the origin of flight in birds. BMC Genomics 17, 371.
Xu et al. 2014. An integrative approach to understanding bird origins. Science 346, 1253293.