Madtom
Encyclopedia
Madtoms or stonecats are catfish
es (order
Siluriformes) of the genus
Noturus of the family
Ictaluridae
. It is the most speciose group of catfish in North America
.
Nearly one half of the species of madtom catfishes was described in the single comprehensive revision of the group. Morphology
is very conserved in this genus; most of the species look very similar and it is difficult to tell them apart with the usual meristic
and morphometric
characters used to identify species. The more conspicuously variable attributes of these secretive fishes are features of pigmentation, which also are more difficult to quantify and often vary according to substrate
and water quality. These species have small to tiny or fragmented ranges
, and aspects of pigmentation are important diagnostic characters of each. Over one quarter of the recognized species diversity in Noturus remains undescribed.
A number of madtom species are narrowly distributed and extremely rare, and thus are at great risk of extinction
. N. trautmani may even be extinct, having been last collected in 1957.
Catfish
Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Noturus of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Ictaluridae
Ictaluridae
The Ictaluridae, sometimes called Ictalurids, are a family of catfish native to North America, where they are important food fish and sometimes as a sport fish. They include fish commonly known as bullheads, madtoms, channel catfish, and blue catfish....
. It is the most speciose group of catfish in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
.
Nearly one half of the species of madtom catfishes was described in the single comprehensive revision of the group. Morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
is very conserved in this genus; most of the species look very similar and it is difficult to tell them apart with the usual meristic
Meristics
Meristics is an area of ichthyology which relates to counting quantitative features of fish, such as the number of fins or scales. A meristic can be used to describe a particular species of fish, or used to identify an unknown species...
and morphometric
Morphometrics
Morphometrics refers to the quantitative analysis of form, a concept that encompasses size and shape. Morphometric analyses are commonly performed on organisms, and are useful in analyzing their fossil record, the impact of mutations on shape, developmental changes in form, covariances between...
characters used to identify species. The more conspicuously variable attributes of these secretive fishes are features of pigmentation, which also are more difficult to quantify and often vary according to substrate
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
and water quality. These species have small to tiny or fragmented ranges
Range (biology)
In biology, the range or distribution of a species is the geographical area within which that species can be found. Within that range, dispersion is variation in local density.The term is often qualified:...
, and aspects of pigmentation are important diagnostic characters of each. Over one quarter of the recognized species diversity in Noturus remains undescribed.
A number of madtom species are narrowly distributed and extremely rare, and thus are at great risk of extinction
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
. N. trautmani may even be extinct, having been last collected in 1957.