Submission Type
Poster
Start Date
4-26-2023
Abstract
The common Ostrich (Struthio camelus) is a member of a large clade of flightless birds known as the ratites. The ratites are morphologically classified by their absence of a keeled sternum that, in flighted birds, provides a large surface area for flight muscle attachment. Although morphology in flighted birds is relatively constrained, the lack of selective pressures in ratites has led to increased variability in the wing. The skeleton of S. camelus exhibits numerous adaptations related to cursoriality, such as a double patella, shortened wing skeleton, and a lightweight pelvic girdle. Though their wings may not be capable of flight, they are used for balance while running and in mating displays. However, it is unclear whether these functional roles constrain the potential variability in the forelimb bones. Geometric morphometric methods and a principal component analysis (PCA) were used to quantify the variation of the individual forelimb elements. Photographs from a set of sixteen scapula and eighteen humeri were analyzed using these methods. Digital landmarks were placed on homologous points on each specimen, while semi landmarks placed between the landmark points were used to capture the curved portions of the bones. After conducting a PCA, substantial variation was observed between individuals as well as between the left and right sides of a single individual. Further analysis will be conducted to identify variation and asymmetry between S. camelus and other ratite taxa in order to better understand the link between function and variability in their evolution.
Recommended Citation
Marzec, Isabel, "352 - Quantifying variation of the ostrich wing (Aves: Paleognathae)" (2023). GREAT Day Posters. 49.
https://knightscholar.geneseo.edu/great-day-symposium/great-day-2023/posters-2023/49
Included in
352 - Quantifying variation of the ostrich wing (Aves: Paleognathae)
The common Ostrich (Struthio camelus) is a member of a large clade of flightless birds known as the ratites. The ratites are morphologically classified by their absence of a keeled sternum that, in flighted birds, provides a large surface area for flight muscle attachment. Although morphology in flighted birds is relatively constrained, the lack of selective pressures in ratites has led to increased variability in the wing. The skeleton of S. camelus exhibits numerous adaptations related to cursoriality, such as a double patella, shortened wing skeleton, and a lightweight pelvic girdle. Though their wings may not be capable of flight, they are used for balance while running and in mating displays. However, it is unclear whether these functional roles constrain the potential variability in the forelimb bones. Geometric morphometric methods and a principal component analysis (PCA) were used to quantify the variation of the individual forelimb elements. Photographs from a set of sixteen scapula and eighteen humeri were analyzed using these methods. Digital landmarks were placed on homologous points on each specimen, while semi landmarks placed between the landmark points were used to capture the curved portions of the bones. After conducting a PCA, substantial variation was observed between individuals as well as between the left and right sides of a single individual. Further analysis will be conducted to identify variation and asymmetry between S. camelus and other ratite taxa in order to better understand the link between function and variability in their evolution.
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