Florida Museum of Natural History

Margined Madtom
Noturus insignis

Margined Madtom

Photo by L. M. Page
Adult male from Roanoke R., Roanoke Co., VA
108 mm SL, Collected 30-April 1979, INHS 27134


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MARGINED MADTOM
Noturus insignis (Richardson 1836)

Identification: The body of the Margined Madtom is yellow to slate gray above and white or light below. The fins are yellow or light gray and the median fins, except for the adipose fin, have a black edge. Fin borders are blackest in clear streams and may be only dusky in color in turbid water. Individuals in the Dan River, Virginia, have dark spots on the body and fins. The upper jaw projects beyond the lower jaw. The rear edge of the pectoral spine has large teeth. The caudal fin edge is straight or slightly rounded. The anal fin has 15-21 rays. To 6 in. (15 cm) total length.

Range: The Margined Madtom is found on the Atlantic Slope from the St. Lawrence River and Great Lakes drainages, southern Quebec and Ontario, to the upper Altamaha River drainage in Georgia. It also is found in the upper Kanawha (New) River system in Virginia and North Carolina, and the upper Monongahela River system in Pennsylvania and Maryland. The Margined Madtom has been introduced into the Merrimack River, New Hampshire, and the upper Tennessee River drainage in Virginia and Tennessee. This species is common in the U.S., but is protected in Canada as a threatened species.

Habitat: The Margined Madtom inhabits rocky riffles and runs of clear, fast creeks and small to medium rivers.

Similar species: The Slender Madtom, Noturus exilis, is the only other madtom to have black borders on its fins, but differs from the Margined Madtom in that the jaws are equal (upper jaw does not project beyond lower jaw), and there is a large light yellow spot on the nape and a smaller one on the rear of the dorsal fin base.


distribution map

Distribution Map