Comprehensive DescriptionRead full entry
Completely aquatic and gilled throughout life. The dwarf waterdog is the smallest member of the genus Necturus, which includes waterdogs and mudpuppies. All mudpuppies and waterdogs have bushy external gills, two gill slits, a laterally compressed tail, and four toes on front and hind feet. Adult dwarf waterdogs are 11.5-19 cm total length, and the tail is slightly less than 40% of total length. Sexually mature males can be distinguished by the swollen cloaca and pair of enlarged cloacal papillae that project posteriorly. Females have a proportionally longer tail than males. Coloration is generally a uniform slate gray to brown or dark olive above, normally without spots. Ventral color is dirty white and without spots, although a few may encroach at the edges of the venter. Dorsal spots are seen in some North Carolina populations. Spotted N. punctatus may be distinguished from the spotted N. lewisi by differences in size (N. lewisi is larger) and ventral coloration (N. punctatus has an unspotted venter, while N. lewisi is spotted). Also, spotted N. punctatus do not co-occur with N. lewisi. Hatchlings are uniformly brown dorsally, without stripes seen in other juvenile Necturus, like N. maculosus (Dundee 1998; Petranka 1998).