Geometric Morphometric Analysis of Intervertebral Variation in Colubrid Snakes
Location
Ballroom
Start Date
4-12-2019 9:00 AM
End Date
4-12-2019 2:30 PM
Poster Number
3
Faculty Sponsor’s Department
Geosciences
Name of Project's Faculty Sponsor
Dr. Blaine Schubert
Type
Poster: Competitive
Project's Category
Evolutionary Biology, Morphology, Paleobiology
Abstract or Artist's Statement
Snake vertebrae are common throughout the Cenozoic fossil record, but identification of isolated vertebrae often proves difficult due to inter- and intra-columnar variability. Most fossil identifications are based on comparisons with disarticulated modern specimens, with a focus on mid-trunk vertebrae. One focus of this study was to determine the necessity of identifying a true mid-trunk vertebra prior to identification and to develop a method of locating the columnar position of an isolated vertebra for both modern and fossil identifications. Colubrid genera Farancia and Heterodon were chosen for the analysis because they share distinct morphological similarities, articulated modern specimens were available, and fossil species in these genera need to be reassessed. Every third pre-cloacal vertebra was selected from each specimen to undergo geometric morphometric analysis on its anterior face. Relative warp analyses detailed the inter-columnar variation of each specimen and found that the only significant difference in the column was between the anterior most vertebrae, which are already identifiable, and the remainder of the pre-cloacal vertebrae. Despite concern, the convention of using mid-trunk vertebrae for identification may prove accurate for these genera. Due to Farancia and Heterodon’s vertebral similarities, a discriminant function analysis was utilized to distinguish the two genera from one another. To evaluate this method’s utility in paleontology, vertebrae of two extinct species, Heterodon brevis and Paleofarancia brevispinosus, will undergo identical morphometric and discriminant analyses. This study also emphasizes the need for more modern snake skeletons in collections and the necessity of stringing the vertebral column prior to disarticulation.
Geometric Morphometric Analysis of Intervertebral Variation in Colubrid Snakes
Ballroom
Snake vertebrae are common throughout the Cenozoic fossil record, but identification of isolated vertebrae often proves difficult due to inter- and intra-columnar variability. Most fossil identifications are based on comparisons with disarticulated modern specimens, with a focus on mid-trunk vertebrae. One focus of this study was to determine the necessity of identifying a true mid-trunk vertebra prior to identification and to develop a method of locating the columnar position of an isolated vertebra for both modern and fossil identifications. Colubrid genera Farancia and Heterodon were chosen for the analysis because they share distinct morphological similarities, articulated modern specimens were available, and fossil species in these genera need to be reassessed. Every third pre-cloacal vertebra was selected from each specimen to undergo geometric morphometric analysis on its anterior face. Relative warp analyses detailed the inter-columnar variation of each specimen and found that the only significant difference in the column was between the anterior most vertebrae, which are already identifiable, and the remainder of the pre-cloacal vertebrae. Despite concern, the convention of using mid-trunk vertebrae for identification may prove accurate for these genera. Due to Farancia and Heterodon’s vertebral similarities, a discriminant function analysis was utilized to distinguish the two genera from one another. To evaluate this method’s utility in paleontology, vertebrae of two extinct species, Heterodon brevis and Paleofarancia brevispinosus, will undergo identical morphometric and discriminant analyses. This study also emphasizes the need for more modern snake skeletons in collections and the necessity of stringing the vertebral column prior to disarticulation.