Fatlips minnow
The fatlips minnow is a species of suckermouth minnow that was first described in the upper Tennessee River system. No fewer than 20 specimens were used for description, and the epithet crassilabrum was assigned to the species, separating it from Phenacobius catostomus, with which it had previously been identified. The first holotype specimen collected in 1947 was an adult female in length from the River.
Geographic distribution
The distribution of the fatlips minnow is restricted to North America, where it occurs in the upper Tennessee River drainage in western Virginia, western North Carolina, eastern Tennessee and northeastern Georgia. Its habitat is gravel and riffles in small to medium creeks. The fatlips minnow is believed to have arisen from a P. catostomus -like stock population that re-invaded the upper Tennessee River via reciprocal stream piracy. A genetic sister relationship between P. crassilabrum and P. uranops has been consistently resolved. The ranges of P. crassilabrum and P. uranops complement one another in the Tennessee River system, with the former opting for higher elevations. In Virginia, P. crassilabrum occupies the lower free-flowing portion of the South Fork of Holston River and Laurel Creek.There are documented instances of nonindigenous occurrences of Phenacobius species; these are believed to be a result of fishermen releasing their unused baitfish into local bodies of water. The current population of P. crassilabrum is presumed to be about 10,000 individuals.