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.

Heritable Variation in a Family-Diagnostic Trait

“…The vast majority of these studies do not include Central Highland specimens because of species range limitations or sampling omissions. However, the few reports that do include Central Highland specimens conclude that these populations are most closely related to nearby southwestern populations (Strange and Burr 1997;Walker et al 1997). The lone exception is a phylogeographic study of the giant permanently aquatic salamander Cryptobranchus alleganiensis (Routman et al 1994).…”

Molecular Phylogeny of North Mediterranean Freshwater Barbs (Genus Barbus: Cyprinidae) Inferred from Cytochrome b Sequences: Biogeographic and Systematic Implications

“…Primary (or true) freshwater fish are of great value for zoogeographic studies because, being unable to 175 cross saline waters (30-36 ppm), they depend on water routes for movement and dispersal and their evolution is therefore strictly correlated with the history of hydrographic networks (Bianco, 1989;Strange and Burr, 1997).…”

Phylogeographic and population genetic analyses reveal Pleistocene isolation followed by high gene flow in a wide ranging, but endangered, freshwater mussel

“…In eastern North America, it has been proposed that current species distributions and genetic structure at both intra-and interspecific levels were formed through pre-Pleistocene vicariance (Mayden, 1985;Wiley and Mayden, 1985), geographic isolation through multiple glacial refugia during the Pleistocene glaciations, and post-glacial dispersal with secondary contact (Near et al, 2001;April et al, 2013). Phylogeographic studies have identified changes in drainage patterns through geological history as the major component forming current patterns of genetic variation of freshwater organisms in North America (Strange and Burr, 1997;Near et al, 2001;Berendzen et al, 2003). For example, populations in previously glaciated regions often show reductions in genetic diversity due to founder effects following dispersal from refugia, and signs of range expansion (Bernatchez and Wilson, 1998;Berendzen et al, 2003).…”