Intraspecific Phylogeography of North American Highland Fishes: A Test of the Pleistocene Vicariance Hypothesis

Abstract

The highland fish fauna of eastern North America consists of Appalachian and Ozark centers of endemism separated by the intervening Glacial Till Plains. Clades within these areas are more closely related phylogenetically to each other than to clades occurring in the intervening formerly glaciated region, suggesting that the Pleistocene glaciations fragmented a widespread highland region and its associated fauna. Alternatively, it is possible that these faunal assemblages predate the glaciations or that recent dispersals may have been more important than vicariance in determining faunal compositions. We examined the relationships among mitochondrial DNA (mtDNA) haplotypes within five clades of highland fishes, each with a distribution suggestive of a Pleistocene vicariance event. Darters of the subgenera Litocara and Odontopholis have distributions and mtDNA relationships that are consistent with the Pleistocene integration and burial of the Teays-Mahomet valley, a major drainage of the early Pleistocene. The distribution and mtDNA relationships among subspecies of Erimystax dissimilis are not consistent with Pleistocene vicariance, but relationships among Appalachian haplotypes are consistent with the late Pleistocene integration of the modern Ohio River system. Both Cottus carolinae and the Fundulus catenatus species group have representatives in the Mobile basin consistent with pre-Pleistocene divergences. Three haplotype clusters were found in C. carolinae, corresponding to the Appalachian, Ozark, and upper Kanawha River populations. However, Appalachian and Ozark F. catenatus populations are paraphyletic with respect to each other. This, coupled with a relatively low degree of sequence divergence, suggests that no long-term barriers to gene flow exist for C. carolinae and F. catenatus. These three distinct phylogeographic patterns indicate that Pleistocene vicariance is not the only explanation for the Appalachian-Ozark distribution of highland fish communities.

Reproductive ecology of the threatened and endemic freshwater mussel Lampsilis bracteata

“…A higher compatibility with sympatric host populations compared with allopatric host populations may be expected where different species or genetically distinct populations of fish are available to mussel populations, so that local adaptations might evolve (Eckert, 2003;Riusech & Barnhart, 2000;St. John White et al, 2017;Strange & Burr, 1997). Compatibility has been shown to decrease as isolation between the mussel source and fish source increased (St. John White et al, 2017) and host suitability was found to be higher on host fish within the natural distribution range of the mussel (Taeubert et al, 2010), but this tendency towards higher success on sympatric host fish is not universal.…”

The Himalayan Uplift and the Evolution of Aquatic Biodiversity Across Asia: Snowtrout (Cyprininae: Schizothorax) as a Test Case

“…Episodic flooding, on the other hand, allowed antecedent streams to down-cut, with headwaters subsequently being eroded and basins concomitantly expanding, with large-scale dispersals being promoted [29]. These alterations (i.e., captures, diversions, beheadings; [30]) not only extended the distribution of fishes into adjacent basins [31], but also facilitated hybridization [32,33,34], a process that has confound both taxonomists and managers (and continues to do so).…”

Riverscape community genomics: A comparative analytical approach to identify common drivers of spatial structure

“…Similar patterns were observed at smaller scales among drainages within the study region, as reported for White River crayfish (Fetzner & DiStefano, 2008). While the Lower White and Black rivers are certainly contemporary large-river habitats, both would have been much larger pre-Pleistocene when together they represented the main channel of the Old Mississippi River (Mayden, 1988;Strange & Burr, 1997). This large-river habitat would have separated the eastern and western highland tributaries, with inhospitable habitat for upland species.…”

“…Organisms within such dendritic networks are demonstrably impacted by the physical structure of the habitat (Peterson et al, 2013;White et al, 2020), with genetic relatedness as a surrogate for the underlying structural hierarchy (Hughes et al, 2009). While this is most apparent within the contemporary structure of river networks, their historic structure, i.e., paleohydrology, also serves to bookmark genetic diversity (Mayden, 1988;Strange & Burr, 1997). Moreover, the hierarchical complexity of these networks will likewise dictate population processes, as reflected within genetic diversities and divergences (Chiu et al, 2020;Hopken et al, 2013;Thomaz et al, 2016).…”