| dc.description.abstract | Anchialine habitats are found within underwater subterranean coastal cave systems and contain a vast array of stygobitic taxa. Due to the inherent difficulties of accessing underwater cave systems, the evolutionary history of many anchialine taxa is not well-known. Anchialine fauna often exhibit globally disjunct distribution patterns that are not readily explained by dispersal or vicariant processes. The objective of this dissertation is to evaluate the evolutionary relationships and distribution within both model crustacean taxa, Remipedia and genus Typhlatya using an integration of ecological, molecular, and morphological evidence to elucidate general biogeographic trends of anchialine fauna. The first study compares the mandibular gnathal edge amongst remipede genera and finds notable disparity amongst the mouthparts, suggesting different feeding strategies may be used across taxa. Additionally, mandibular comparison suggests phylogenetic uncertainty regarding the placement of a few taxa within Remipedia. Using the most comprehensive molecular dataset for Remipedia to date, the second study recovers a phylogeny incongruent with previous studies, suggesting some clades need to be re-examined. The distribution patterns within the class were reassessed to reveal species ranges extending across islands of the same shallow-water banks, but not between banks. This may suggest that deep-water acts as a barrier and potential driver of diversification within select anchialine fauna. The third study compares the interspecies relationships within remipede genus Godzillius, with the inclusion of a description for new species, Godzillius louriei sp. nov. The final study explores the phylogeny and biogeographic distribution of Typhlatya species within the Yucatan Peninsula. This study finds that, contrary to previous marine-colonizing hypotheses, Typhlatya species from the Yucatan may have a fresh/oligohaline ancestor which is hypothesized to have traveled across shallow landspans between the Yucatan Peninsula and Cuba. In summary, these findings suggest that the distribution patterns of anchialine fauna are largely driven by vicariant processes, such as the historic migration of shallow-water platforms. Dispersal may be possible through spelean corridors, but the capabilities and barriers of such migration is likely unique to each taxon and remains a significant question for future research. | |
