Campus Only Senior Thesis
Bachelor of Arts
Organismal Biology and Ecology
Dr. Catherine McFadden
Dr. Elise Ferree
© 2023 Asha Peddada
As coral species rapidly decline, it is more important than ever to understand the ecological characteristics of coral reefs for effective conservation. This requires establishing baseline knowledge of species abundance, distribution, and diversity, all of which depend on accurate identification and delimitation of coral species. Employing a molecular taxonomic approach, species were defined as Molecular Operational Taxonomic Units (MOTUs) based on established genetic distance thresholds. By integrating Philippines samples with existing datasets for genera Sclerophytum, Lemnalia/Paralemnalia, Cladiella, Capnella, Klyxum, and family Xeniidae, our understanding of octocoral biodiversity and geographical distribution across the Philippines as well as octocoral distributions in the Indo-Pacific can be expanded. PCR was used to amplify the nuclear ribosomal gene 28S of randomly collected samples from the Philippines. Sequences were edited and aligned with ~2000 sequences from other specimens collected at other locations across the Indo-Pacific. β-diversity and Sørenson's dissimilarity of each genus and family were measured from presence/absence matrices of MOTUs vs. sampling site, and visualized using hierarchical clustering plots. Four new cryptic species were found to be regionally endemic to the Philippines. The prevalence of a single MOTU in the Paralemnalia genus suggests 28S may not be a good barcode for distinguishing Paralemnalia and Lemnalia species. Turnover is responsible for high β-diversity of octocorals in the Indo-Pacific, indicating that species composition depends on regional variation. Surprisingly, only Xeniidae and Klyxum exhibit close clustering with South China Sea locations. These findings have implications for octocoral conservation strategies and emphasize regional variation in Indo-Pacific species composition.
Peddada, Asha, "DNA Barcoding Illuminates Biodiversity and Geographical Distributions of Indo-Pacific Shallow-Water Octocorals off the Coast of the Philippines" (2023). Pitzer Senior Theses. 182.
This thesis is restricted to the Claremont Colleges current faculty, students, and staff.