Submission Type
Poster
Abstract
Paleognathae is a group of flightless birds largely characterized by the absence of the keeled sternum. As they diverged from their flighted ancestors, most palaeognaths developed cursorial traits, such as greater body mass and elongated hindlimbs, and concomitant with this was the reduction of the forelimbs, which were no longer needed for flight. This study investigates the forelimb variation within and between different paleognathous species to determine which behaviors and environmental pressures may have contributed most to the forelimb morphologies of extant taxa. Differences in the forelimb elements of males and females, indicating sexual dimorphism in the wing, would suggest that variation results from sex-specific functions such as mating displays. Comparison between captive and wild populations could show variation resulting from the presence of competition, predation, and other environmental factors. However, initial results suggest there is no clear pattern of sex-specific variability among Struthio camelus individuals. Using two-dimensional geometric morphometrics, principal component (PC) data for species representing all paleognath families were analyzed to investigate variation between forelimb elements and also to test adherence to the hypothesized pattern of limb reduction in which reduction occurs distal to proximal. These methods allow us to contrast interspecies and intraspecies variation to quantify how functional demands on the wing affect morphological variation of the bones and thus better understand the evolutionary relationship between form and function in cases of limb reduction.
Recommended Citation
Marzec, Isabel and Burch, Sara, "085 - Investigating Drivers of Variation in the Paleognath Wing" (2025). GREAT Day Posters. 24.
https://knightscholar.geneseo.edu/great-day-symposium/great-day-2025/posters-2025/24
085 - Investigating Drivers of Variation in the Paleognath Wing
Paleognathae is a group of flightless birds largely characterized by the absence of the keeled sternum. As they diverged from their flighted ancestors, most palaeognaths developed cursorial traits, such as greater body mass and elongated hindlimbs, and concomitant with this was the reduction of the forelimbs, which were no longer needed for flight. This study investigates the forelimb variation within and between different paleognathous species to determine which behaviors and environmental pressures may have contributed most to the forelimb morphologies of extant taxa. Differences in the forelimb elements of males and females, indicating sexual dimorphism in the wing, would suggest that variation results from sex-specific functions such as mating displays. Comparison between captive and wild populations could show variation resulting from the presence of competition, predation, and other environmental factors. However, initial results suggest there is no clear pattern of sex-specific variability among Struthio camelus individuals. Using two-dimensional geometric morphometrics, principal component (PC) data for species representing all paleognath families were analyzed to investigate variation between forelimb elements and also to test adherence to the hypothesized pattern of limb reduction in which reduction occurs distal to proximal. These methods allow us to contrast interspecies and intraspecies variation to quantify how functional demands on the wing affect morphological variation of the bones and thus better understand the evolutionary relationship between form and function in cases of limb reduction.
Comments
Sponsored by Sara Burch