Two new Madtom catfish at risk

Two new species of Madtom catfish discovered in the USA's Tennessee River drainage have such a small distribution that they may be at risk of extinction.

The new Noturus catfishes, which are members of the family Ictaluridae, were discovered in a group of rivers which flow into the Tennessee River, and are not known from other waters, so could become endangered if their habitats become damaged.

One of the new fishes, which has been named Noturus fasciatus in a paper in the journal Copeia, was found in the Green River drainage of central Kentucky and north-central Tennessee.

The same fish has been captured in the past, but has been misidentified as N. elegans, and is believed to have a distribution which is confined to the Duck River and two small tributaries of the lower arm of the Tennessee River.

The second new catfish species, which was named N. crypticus, has a tiny range and is currently known only from the Little Chucky Creek in Greene County, Tennessee.

Brooks Burr, David Eisenhour and James Gradyc, who described the new fish say that all three species are closely related to each other and can be distinguished by their colour, body shape and differences in the number of anal fin rays.

The Madtoms live in riffle areas in small to medium-sized streams and live in or under gravel, rubble and slabs of rock.

The scientists say that further work is required to determine how endangered the fish are: "The limited geographic distributions of the two new species places them at greater risk of extinction, warranting comprehensive evaluation of their life histories, demographic characteristics, recruitment rates, and nesting requirements."

For more details see the paper: Burr, BM, DJ Eisenhour and JM Grady, 2005. Two New Species of Noturus (Siluriformes: Ictaluridae) from the Tennessee River Drainage: Description, Distribution, and Conservation Status. Copeia 2005: 783-802.