Date of Award
2025-05-01
Degree Name
Master of Science
Department
Biological Sciences
Advisor(s)
Eli Greenbaum
Abstract
Philothamnus is a genus of nonvenomous colubrid snake endemic to sub-Saharan Africa. Forest retraction during Late Mioceneâ??Pliocene global cooling facilitated an adaptive radiation of this ancestrally forest-adapted genus into the expanding savanna biome. Efforts to parse the taxonomic relationships resulting from this diversification have been stymied by widespread morphological conservatism. This study focuses on two wide-ranging species of Philothamnus with high potential for cryptic diversity, P. semivariegatus and P. heterolepidotus. Using molecular and morphological data, my goal was to produce a phylogeny with detailed descriptions of cryptic diversity to resolve their taxonomy. I used Maximum likelihood and Bayesian inference methods on a molecular dataset of three mitochondrial (16S, cyt b, and ND4) and two nuclear (c-mos and RAG1) genes to produce phylogenies, and meristic and mensural data were collected from museum specimens to evaluate morphological variation. Six morphologically diagnosable, species-level clades were identified within the P. semivariegatus complex with diversification occurring primarily in the Late Miocene â?? Pliocene. One of these candidate species is found across much of tropical Africa and shows strong population structure, likely owing to cyclic expansion and contraction of forest habitats during this time period. The other five are located in southern Africa, where the influence of geographical features such as the Benguela Current and Great Escarpment on habitat heterogeneity likely drove diversification. Three species-level clades were identified in the P. heterolepidotus complex with diversification taking place in the Pliocene when tectonic uplift and rifting reconfigured the hydrology of Central Africa. This likely had a profound influence on the biogeography of P. heterolepidotus whose ecology is closely tied to water sources.
Language
en
Provenance
Received from ProQuest
Copyright Date
2025-05
File Size
253 p.
File Format
application/pdf
Rights Holder
Everett Madsen
Recommended Citation
Madsen, Everett, "Phylogenetics And Integrative Taxonomy Of Two Species Of African Bush Snakes, Philothamnus Semivariegatus And P. Heterolepidotus (squamata: Colubridae)" (2025). Open Access Theses & Dissertations. 4405.
https://scholarworks.utep.edu/open_etd/4405