The corrugated darter (Etheostoma basilare) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the eastern United States only known from Caney Fork, Tennessee, where it has been shown to have as many as five subgroups. They are active hunters which prey on insects, fry, and possibly young snails. Multiple species and subspecies of these darters can coexist where substrate is varied, so this must be carefully preserved to accommodate many similar species. With the warming of spring, E. basilare enters its breeding cycle and males develop their dimorphic coloration. Like most darters, it hugs the stream bed, using its body shape and fin posture to maintain its position. This lifestyle which is so dependent upon the benthic architecture of the stream is highly impacted by disturbance, which can be the result of increased or decreased flow from dams, introduction of polluted debris, or particulate size change due to erosion. Dams, in particular, pose a large threat to this species due to the effects of siltation, which can over time fill in streambed substrate gaps, destroying nesting sites and suffocating any eggs already laid. In addition, different species and subspecies of darter are highly adapted to a given substrate size, which insinuates that this habitat homogenization could result in a negative impact on the existent E. basilare subspecies diversity and on the darter ecological balance as a whole. Distribution The corrugated darter is endemic to the upper section of the Caney Fork and Collins River in eastern Tennessee, both of which are part of the Cumberland River drainage. It has been consistently present in this area since its original speciation, upon which its geographic home has had considerable influence. Formed by the abundance of melt from the receding North American glaciers, which presumably carried the darter ancestor with it, this part of the river system has been mostly isolated from neighboring water systems by this drastic geographic change, creating a likely environment for the genetic deviation of many darter species, E. basilare included. This effect can also be observed at a smaller scale. Conditions in this part of the river have enabled the corrugated darter to further diverge into five closely related subgroups, highlighting the adaptability of the species and how even small habitat differences can drive divergence. Ecology