Date of Award
Doctor of Philosophy
Arshad M. Khan
How do traits vary across the tree of life? Our ability to address this question is diminished if: A taxonomic group has a poorly sampled phylogeny, a species goes extinct before their systematic position is resolved, or a trait is inadequately characterized for detailed studies. In the current era of mass extinction, it is imperative to not only accelerate species discovery through traditional studies in taxonomy and expeditionary research, but also to increase rescue efforts for all types of data before poorly understood species and potentially undescribed traits are lost. Here, an integrative taxonomic approach was used and novel methods were developed for preserving neuroanatomy in arboreal lizards (Chamaeleonidae) from the Albertine Rift, a Central African biodiversity hotspot. Species-tree and gene-tree methods were used on DNA data to test several phylogeographic hypotheses regarding the relative influence of geology, climate, and environment on the evolutionary histories of two understudied chameleon species, Rhampholeon boulengeri and Kinyongia adolfifriderici. Phylogeographic results revealed unanticipated biogeographic scenarios and underestimated species richness in pygmy chameleons (genus Rhampholeon). Morphometrics from museum specimens, including type material were compared to results from molecular phylogenies to describe three new forest chameleon species (genus Kinyongia). With a greater knowledge of ancestry in these two species groups, a protocol for preserving brains in suboptimal-field conditions was developed. This method was validated to show that samples preserved in the field could be utilized to describe neuroanatomy from gross anatomical down to cellular scales. Significantly, this protocol revealed that the detailed characterization of neuroanatomical traits could be achieved from a novel data source-field-preserved brains. This new methodology represents the beginnings of a comprehensive analysis aimed at studying vertebrate brain evolution by incorporating greater species diversity. In sum, as we seek to discover Earth's biodiversity during a period when the extinction rate is exceptionally high, we must explore new methods aimed at integrating data across a wide variety of scientific disciplines, while continuing to describe species and traits using traditional approaches in taxonomy and systematics.
Received from ProQuest
Hughes, Daniel, "Comparative Phylogeography, Taxonomy, And Neuroanatomy Of Montane Chameleons In The Albertine Rift, Central Africa" (2018). Open Access Theses & Dissertations. 1455.