Necturus

The genus Necturus is under scrutiny by herpetologists. 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: ==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 . == 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. 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. == References ==