Discordant patterns of morphological and molecular change in broadtail madtoms (genus Noturus)

Abstract

Two morphologically distinct forms of an undescribed madtom catfish (Noturus sp.) occur in the rivers and lakes of southeastern USA. 'Lake' broadtail madtoms are endemic to Lake Waccamaw and are probably related to nearby 'river' broadtail populations. To investigate phylogenetic relationships, we surveyed mitochondrial DNA (mtDNA) sequence variation in 'lake' and 'river' broadtails and other members of the genus Noturus. Mitochondrial rDNA data suggest a sister group relationship between broadtail madtoms and N. insignis, not N. leptacanthus as posited previously. Population-level analyses using additional mtDNA characters (NADH dehydrogenase subunit 2 (ND2) and cytochrome b (Cytb)) identified two highly divergent genetic lineages within broadtail madtoms that do not correspond to the morphological designations 'river' and 'lake'.

Gene–Gene Concordance and the Phylogenetic Relationships among Rare and Widespread Pygmy Sunfishes (Genus Elassoma)

“…Perhaps more interesting than the issue of species limits among pygmy sunfishes is mounting evidence from pygmy sunfishes (Quattro et al, in press) and unrelated species (Bennetts et al, 1999;Collins et al, 1999) for widespread genetic differentiation among populations in coastal Carolina rivers and a high rate of endemism among southeastern Atlantic Coastal Plain drainages (Jenkins and Palmer, 1978;Jenkins and Lachner, 1980;Jenkins and Birkhead, 1994;Bennetts et al, 1999). With evidence of genetic divergence among populations in coastal Carolina drainages and no evidence for vicariance within the region, it would be interesting to estimate phylogenetic support for vi-224 cariance or similar shared historical influences by reconstructing relationships across drainages with other species.…”

Evolutionarily independent genes and genomes and insights on genetic structure, evolution and conservation of the collis group of darters

“…For example, population genetic variation is strongly structured across broadtail madtom (Noturus) populations, including a strongly supported Pee Dee River clade (Bennetts et al, 1999). Genetic variation among Coastal Plain pygmy sunfishes (Elassoma) is also characterized by significant among-drainage divergence (Quattro, Jones & Rohde, 2001b).…”

“…For example, the Pee Dee River broadtail madtom population is an ESU (Bennetts et al, 1999), as are the Waccamaw and Santee River populations of Elassoma boehlkei (Quattro et al, 2001b), the New/Savannah River populations of Table 1 for population codes and Tables 3-6 Elassoma okatie (Quattro et al, 2001b), and the Altamaha River and Savannah River populations of M. robustum (Wirgin et al, 2001). According to Moritz's (1994) conservative estimators of long-term isolation, all populations of the collis group are ESUs.…”

“…Etheostoma saludae (the Saluda darter) is entirely restricted to two tributaries of the Congaree River, South Carolina, whereas the closely related Etheostoma collis (the Carolina darter) occurs only within the Catawba River, Pee Dee River, Cape glaciation, 'deep' (historical) population separations are expected to accrue between adjacent drainages (Hewitt, 2000). Indeed, previous studies have revealed significant genetic components of variation among river systems in a variety of south-eastern freshwater fish species (Bennetts et al, 1999;Quattro, Jones & Oswald, 2001a;Wirgin, Opermann & Stabile, 2001;Quattro et al, 2002). However, several of the now-isolated rivers in which collis group species occur were components of larger, ancient river systems that traversed the exposed Continental Shelf during glaciation, providing the potential for gene flow across drainages and more complex divergence patterns.…”

Parasites of the Carolina Bay Lake-EndemicFundulus waccamensis(Waccamaw Killifish)

“…Additionally, Lake Waccamaw is home to a population of an undescribed Noturus sp. (broadtail madtom) (Bennetts et al 1999, Rohde et al 2009) and a slightly divergent morphotype of Notropis petersoni Fowler (Coastal Shiner; Krabbenhoft et al 2009a)-a cyprinid originally described as Notropis waccamanus (Hubbs and Raney 1946). A genetically distinct population of Elassoma boehlkei Rohde & Arndt (Carolina Pygmy Sunfish) has sporadic, low-density occurrence in the canals and creeks adjacent to Lake Waccamaw and in a few other localities in the Waccamaw and Santee river basins of South Carolina (Quattro et al 2001, Rohde andArndt 1987).…”