''Noturus hildebrandi'', also known as the least madtom, is a species of

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

. Its native range stretches from the Obion River in Kentucky to the

Homochitto River The Homochitto River (pronounced "ho-muh-CHIT-uh") is a river in the U.S. State of Mississippi. It flows from its source in southwest Mississippi for about west and south, emptying into the Mississippi River between Natchez and Woodville. Acco ...

in Mississippi.

Description

The least madtom is a small slender-bodied fish with a flat head. It measures up to 6.9 centimeters in length. The adipose fin is either clear or white; however, populations in Mississippi sometimes have a dark patch on the adipose fin. Body coloration varies by geography. There are two known subspecies, ''Noturus h. hildebrandi'' and ''Noturus h. lautus. N. h. hildebrandi,'' which inhabits the Homochitto River and Bayou Pierre, has a long head and a mottled coloration. ''N.h. lautus'' lives in the Obion and surrounding rivers; this subspecies has a shorter head and four light-colored oval areas on a red-brown to black back. Males and females are identical in appearance. Most live about 12 to 15 months, dying shortly after reproducing.

Habitat

The least madtom inhabits sandy riffles, mixed rock riffles, creeks, pools, and small rivers. It is commonly found in shallow areas containing submerged logs, sticks, leaves, and other debris.

Reproduction

The least madtom's spawning season lasts from June through August. During this time the males increase in size. The females spawn during their second summer. To prepare for spawning, adults take shelter, either singly or in pairs, under stones, shells, or in debris. An average of 19 orange

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...

s are laid in these areas. Both parents guard the nest as the eggs develop. Eggs hatch within 8 to 9 days. Yolk resorption takes about 9 to 10 days after hatching.

Diet

The least madtom's diet consists of 16 different

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

taxa.

Midge A midge is any small fly, including species in several families of non-mosquito Nematoceran Diptera. Midges are found (seasonally or otherwise) on practically every land area outside permanently arid deserts and the frigid zones. Some mid ...

s make up the majority of their diet, followed by caddisfly larva. Crustaceans are consumed only in late winter and early spring. The size of prey is proportional to body size.

References

{{Taxonbar, from=Q3753214 Noturus Freshwater fish of the United States Fish of the Eastern United States Endemic fauna of the United States Endemic fauna of Tennessee Fauna of the Southeastern United States Fish described in 1950