Temporal range: 
Eight species (but see text)
Necturus is a genus of aquatic salamanders in the family Proteidae. Species of the genus are native to the eastern United States and Canada. They are commonly known as waterdogs and mudpuppies. The common mudpuppy (N. maculosus) is probably the best-known species – 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.
The genus Necturus is under scrutiny by herpetologists. The relationship between the species is still being studied. In 1991 Collins reelevated N. maculosus louisianensis to full species status as N. louisianensis. Originally described by Viosca as a species, it usually had been considered a subspecies of the common mudpuppy (N. maculosus). However, the interpretation of Collins was not largely followed. Then, a 2018 study confirmed it as a distinct species, with Amphibian Species of the World following these results, although other authorities do not.
There are seven to eight species:
|Image||Scientific name||Common Name||Distribution|
|Necturus beyeri Viosca, 1937
synonym: N. lodingi Viosca, 1937
|western waterdog (formerly the Gulf Coast waterdog) or Mobile mudpuppy. These two names have been recognised as independent species in the past.||Alabama, Louisiana, Mississippi, and Texas.|
|Necturus lewisi Brimley, 1924||Neuse River waterdog||North Carolina.|
|Red River waterdog. Sometimes considered a subspecies of N. maculosus.||southeastern Kansas, southern Missouri, northeastern Oklahoma, Arkansas, and northcentral Louisiana.|
|Necturus maculosus (Rafinesque, 1818)||common mudpuppy||southern section of Canada, as far south as Georgia|
Guyer et al., 2020
|Apalachicola waterdog||southeastern Alabama, the Panhandle of Florida, and southwestern to north-central Georgia.|
|Necturus mounti Guyer et al., 2020||Escambia waterdog||southern Alabama and the Panhandle of Florida.|
|Necturus punctatus (Gibbes, 1850)||dwarf waterdog||from southeastern Virginia to southcentral Georgia.|
Nota bene: 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 of Saskatchewan and from Florida during the Pleistocene.
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 20–25 cm (8–10 in) in total length, but Necturus maculosus is larger and may reach 40 cm (16 in).
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.
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 at late as November.
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. 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.
- ^ "Fossilworks: Necturus".
- ^ a b c d e Frost, Darrel R. (2019). "Necturus Rafinesque, 1819". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 9 June 2019.
- ^ a b c "North American Herpetofauna: Amphibia: Caudata". Centre for North American Herpetology. Retrieved 9 June 2019.
- ^ a b c Vitt, Laurie J.; Caldwell, Janalee P. (2014). Herpetology: An Introductory Biology of Amphibians and Reptiles (4th ed.). Academic Press. pp. 463–465.
- ^ a b c d e Haines, Adam M.; Pennuto, Christopher M. (2022-09-26). "Common Mudpuppy (Necturus maculosus (Rafinesque, 1818)) in Western New York: A Seasonal Comparison of Diet, Body Condition, and Capture Methods". Journal of Herpetology. 56 (3). doi:10.1670/20-141. ISSN 0022-1511. S2CID 252586807.
- ^ a b "Proteidae". AmphibiaWeb. University of California, Berkeley. 2019. Retrieved 9 June 2019.
- ^ Petranka, J.W. (1998). Salamanders of the United States and Canada. Washington, District of Columbia: Smithsonian Institution Press. ISBN 1588343081.
- ^ a b "Necturus louisianensis Viosca, 1938 | Amphibian Species of the World". amphibiansoftheworld.amnh.org. Retrieved 2021-12-16.
- ^ Chabarria, Ryan E.; Murray, Christopher M.; Moler, Paul E.; Bart, Henry L.; Crother, Brian I.; Guyer, Craig (2018). "Evolutionary insights into the North American Necturus beyeri complex (Amphibia: Caudata) based on molecular genetic and morphological analyses". Journal of Zoological Systematics and Evolutionary Research. 56 (3): 352–363. doi:10.1111/jzs.12203. ISSN 1439-0469.
- ^ a b "AmphibiaWeb – Necturus maculosus ". amphibiaweb.org. Retrieved 2021-12-16.
- ^ "Necturus beyeri Viosca, 1937 | Amphibian Species of the World". amphibiansoftheworld.amnh.org. Retrieved 2021-12-17.
- ^ "Fossilworks: Necturus krausei ". fossilworks.org. Retrieved 17 December 2021.
- ^ "PBDB". Necturus Rafinesque (mudpuppy).
- ^ VanDeWalle, Terry; Collins, Suzanne L. (2013). "Salamanders in Your Pocket: a Guide to Caudates of the Upper Midwest". University of Iowa Press.
- ^ a b c d Collins, Merri K.; Spear, Stephen F.; Groves, John D.; Williams, Lori A.; Kuchta, Shawn R. (2019-10-04). "Searching for a Salamander: Distribution and Habitat of the Mudpuppy (Necturus maculosus) in Southeast Ohio Using eDNA as a Rapid Assessment Technique". The American Midland Naturalist. 182 (2): 191. doi:10.1674/0003-0031-182.2.191. ISSN 0003-0031. S2CID 203658126.
- ^ a b c d Lennox, Robert J.; Twardek, William M.; Cooke, Steven J. (2018-08-28). "Observations of Mudpuppy (Necturus maculosus) bycatch in a recreational ice fishery in northern Ontario". The Canadian Field-Naturalist. 132 (1): 61–66. doi:10.22621/cfn.v132i1.2040. ISSN 0008-3550.
- ^ a b Chatfield, Matthew W. H.; Moler, Paul; Richards-Zawacki, Corinne L. (2012-09-11). "The Amphibian Chytrid Fungus, Batrachochytrium dendrobatidis, in Fully Aquatic Salamanders from Southeastern North America". PLOS ONE. 7 (9): e44821. Bibcode:2012PLoSO...744821C. doi:10.1371/journal.pone.0044821. ISSN 1932-6203. PMC 3439441. PMID 22984569.
- Media related to Necturus at Wikimedia Commons