• Necturus is a genus of aquatic salamanders 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 genus is under scrutiny by herpetologists.

• The relationship between the species is still being studied. In 1991 Collins elevated N. maculosus louisianensis to full species status, usually considered a subspecies of the common mudpuppy (N. maculosus), but his interpretation was not largely followed