Florida Museum of Natural History

Northern Madtom
Noturus stigmosus

Northern Madtom

Photo by L. M. Page

Northern Madtom

Photo by M. R. Thomas
Ohio River, IL
45 mm SL, SIUC 52576


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NORTHERN MADTOM
Noturus stigmosus Taylor 1969

Identification: The Northern Madtom has a stout body with the deepest point located beneath the dorsal fin, and a relatively deep caudal peduncle. The body is yellow or medium tan with brown or black mottling above and white to yellow below. The 1st of 4 dark saddles has an irregular front edge that encloses 2 large light spots in front of the dorsal fin. The fins are blotched or banded. The dorsal fin has a dark band at the base and another near the edge of the dorsal fin connected to one another along the front of the fin. The adipose fin has a brown or black band that extends into the upper half but doesn't reach the edge of the fin. The caudal fin has one dark crescent-shaped band in the middle extending forward across the upper and lower caudal rays to the caudal peduncle and another band near the clear edge. The pectoral spine is large with 5-10 prominent teeth on the rear edge and large teeth on the front edge. The caudal fin is straight or slightly rounded and nearly free from the adipose fin. The anal fin has 13-16 rays. To 5 in. (13 cm) total length.

Range: The Northern Madtom is found in Lake Erie and Ohio River basins from western Pennsylvania, southern Ontario, and West Virginia, to the Ohio River in southern Illinois. The species is uncommon and is disappearing on the edges of its range. It is protected in Canada as an endangered species.

Habitat: The Northern Madtom inhabits fast rocky riffles and runs in small to large rivers. It often is found near debris.

Similar species: The Piebald Madtom, N. gladiator, has a bolder pattern, the dark bar in the adipose fin crosses the body to connect with the bar in the anal fin, and the dark crescent-shaped band in the middle of the caudal fin is broadly joined to dark pigment on the caudal peduncle forming 2 distinct yellow spots at the base of the fin. The Neosho Madtom, Noturus placidus, has a dark band restricted to the lower half of the adipose fin and white lower front caudal fin rays. The Frecklebelly Madtom, Noturus munitus, has a more slender caudal peduncle and a black band extending to the edge of the adipose fin. The Mountain Madtom, Noturus eleutherus, has a dark brown bar at the base of the caudal fin, no dark crescent-shaped band in the middle of the caudal fin, no light spots in front of the dorsal fin, and no dark band near the edge of the dorsal fin.


distribution map

Distribution Map