Date of Award

5-2024

Degree Type

Honors College Thesis

Academic Program

Biological Sciences BS

Department

Biological Sciences

First Advisor

Nicole M. Phillips, Ph.D.

Advisor Department

Biological Sciences

Abstract

Family Pristidae contains five of the most critically endangered elasmobranch species: Anoxypristis cuspidata, Pristis pristis, Pristis pectinata, Pristis zijsron, and Pristis clavata. The species of this family have suffered drastic population declines and range reductions due to historic patterns of overexploitation, accidental entanglement, and habitat disruption. The conservation of this taxa has been historically complicated by taxonomic uncertainty, as similar morphologies across species make them exceedingly difficult to identify. A morphological and genetic comparison of sawfish specimens collected globally was conducted in 2013, which supported a reduction in the number of described species from seven to five. However, the study was based on small samples sizes from some geographic regions and limited genetic data. Here, a study was conducted to assess the genetic relationships between and within the currently described species of sawfishes utilizing historic DNA. Tissues were sampled from historic trophy rostra and a 374-bp portion of the mitochondrial 12S rRNA gene was PCR-amplified. Successful amplicons were sequenced and analyzed using MEGA v X and Network v 10.1.10. We found evidence for the splitting of regionally defined genetic subgroups within P. pristis, as is evident by phylogenetic and haplotype analyses. The resulting data may act as a baseline genetic library for future unknown samples, as displayed here. A comprehensive study of the mitogenomes of these species may be needed to further investigate genetic divergence in subgroupings of P. pristis.

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