A Comparative Study of Eggshell Pore Morphology of Palaeognath Birds
Submission Type
Event
Expected Graduation Date
2016
Location
Center for Natural Sciences, Illinois Wesleyan Universtiy
Start Date
4-18-2015 2:00 PM
End Date
4-18-2015 3:00 PM
Disciplines
Biology | Developmental Biology | Ornithology
Abstract
Avian eggshell pores, which allow gas exchange to and from the embryo, vary in size and structure (e.g., diameter, branching pattern, shape, abundance, and dispersion) among species. Previous studies have indicated that eggshell microstructures can contribute to the development of evolutionary hypotheses (phylogenies) of avian taxa. We are focusing on the Palaeognath taxon, which includes the extinct flightless Ratites (Elephant Birds and Moas), the extant flightless Ratites (i.e., Ostriches, Emus, Rheas, Kiwis, Cassowaries), and the extant flighted Tinamous. The purpose of our study is to evaluate whether eggshell pore morphologies are phylogenetically informative characters for Palaeognath birds. We are using a polyurethane-based resin to make three-dimensional corrosion casts of eggshell pore spaces. Preliminary data from the casts of Elephant Bird pore spaces indicate that in one third of the observed fragments, bifurcated branching exists in the palisade layer (the region closest to the external surface). Unbranched pores were cylindrical based on a comparison of pore diameters in the upper, middle, and lower regions.
A Comparative Study of Eggshell Pore Morphology of Palaeognath Birds
Center for Natural Sciences, Illinois Wesleyan Universtiy
Avian eggshell pores, which allow gas exchange to and from the embryo, vary in size and structure (e.g., diameter, branching pattern, shape, abundance, and dispersion) among species. Previous studies have indicated that eggshell microstructures can contribute to the development of evolutionary hypotheses (phylogenies) of avian taxa. We are focusing on the Palaeognath taxon, which includes the extinct flightless Ratites (Elephant Birds and Moas), the extant flightless Ratites (i.e., Ostriches, Emus, Rheas, Kiwis, Cassowaries), and the extant flighted Tinamous. The purpose of our study is to evaluate whether eggshell pore morphologies are phylogenetically informative characters for Palaeognath birds. We are using a polyurethane-based resin to make three-dimensional corrosion casts of eggshell pore spaces. Preliminary data from the casts of Elephant Bird pore spaces indicate that in one third of the observed fragments, bifurcated branching exists in the palisade layer (the region closest to the external surface). Unbranched pores were cylindrical based on a comparison of pore diameters in the upper, middle, and lower regions.