''Necturus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of aquatic

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Proteidae The family (biology), family Proteidae is a group of aquatic Salamander, salamanders found today in the Balkan Peninsula and North America. The range of the genus ''Necturus'' (commonly known as waterdogs or mudpuppies) runs from southern cent ...

Species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of the genus are native to the eastern

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

and

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

. They are commonly known as waterdogs and mudpuppies. The common mudpuppy ''(N. maculosus)'' is probably the best-known

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

– as an amphibian with gill slits, it is often dissected in comparative anatomy classes. The common mudpuppy has the largest distribution of any fully aquatic salamander in North America.

Taxonomy

The genus ''Necturus'' is under scrutiny by

herpetologists Herpetology (from Ancient Greek ἑρπετόν ''herpetón'', meaning "reptile" or "creeping animal") is a branch of zoology concerned with the study of amphibians (including frogs, salamanders, and caecilians (Gymnophiona)) and reptiles (incl ...

. The relationship between the species is still being studied. In 1991, Collins recommended ''N. maculosus louisianensis'' be elevated to full species status as ''N. louisianensis''. Originally described by Viosca as a species, it is usually considered a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

of the common mudpuppy (''N. maculosus''). However, the interpretation of Collins was not largely followed. Petranka, J.W. (1998). ''Salamanders of the United States and Canada''. Washington, District of Columbia: Smithsonian Institution Press. . A 2018 study identified two lineages (Great Lakes and Mississippi River), but did not draw conclusions about species vs. subspecies status ("Our limited samples are consistent with either interpretation." pg. 360). Currently, the Society for the Study of Reptiles and Amphibians considers the Red River mudpuppy to be a subspecies of ''N. maculosus'', but notes that "its taxonomic status requires further research."

Species

There are seven or eight species: ''

Nota bene ( ; plural: ) is the Latin language, Latin phrase meaning ''note well''. In manuscripts, ''nota bene'' is abbreviated in upper-case as NB and N.B., and in lower-case as n.b. and nb; the editorial usages of ''nota bene'' and ''notate bene'' fi ...

'': A binomial authority in parentheses indicates that the species was originally described in a genus other than ''Necturus''. Two known fossil species, '' N. krausei'' and an unnamed species, are respectively known from the

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

Saskatchewan Saskatchewan is a Provinces and territories of Canada, province in Western Canada. It is bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and to the south by the ...

and from Florida during the Pleistocene.

Description

''Necturus'' are paedomorphic: adults retain larval-like morphology with external gills, two pairs of gill slits, and no eyelids. They are moderately robust and have two pairs of short but well-developed limbs and a large, laterally compressed tail. Lungs are present but small. Typical adult size is in total length, but ''Necturus maculosus'' is larger and may reach . ''N. maculosus'' is brown to gray on its back with bluish black spots. There may be spots on its belly, but these spots range from heavily spotted to no spotting. There are dark red bushy gills. Four toes are present per hindlimb.

Reproduction

Females lay eggs under rocks and other large cover objects in late spring and early summer. Females guard nests at least until eggs hatch. Females forage while nest-guarding, but they may eat some of their eggs as a source of energy if other food sources are not readily available. Larvae are believed to stay under the rock as late as November.

Ecology

''Necturus'' occur in surface waters, preferentially with clear water and rocky substrates without silt. ''N. maculosus'' live in lakes, rivers, streams, and creeks. They like shallow waters with low temperatures from autumn to early spring. They are most active in cold temperatures, specifically between 9.1 and 20.2 degrees Celsius. During the day, ''N. maculosus'' seeks refuge under rocks or logs and plant debris. They forage during the night and eat a variety of prey, but have preference for

crayfish Crayfish are freshwater crustaceans belonging to the infraorder Astacidea, which also contains lobsters. Taxonomically, they are members of the superfamilies Astacoidea and Parastacoidea. They breathe through feather-like gills. Some spe ...

. During the winter and spring, ''N. maculosus'' will also eat fish. ''N. maculosus'' are good indicators of ecosystem health. This species has frequently been harmed via bycatch events (primarily passive ice fishing), chemical pollutants, and siltation. Amphibian chytrid fungus (Bd) has been known to affect captive ''N. maculosus'', but it is currently unknown whether it has affected wild ''N. maculosus''.

References

External links

* {{Authority control Proteidae Amphibian genera Extant Paleocene first appearances Taxa named by Constantine Samuel Rafinesque