Comprehensive DescriptionRead full entry
Completely aquatic and gilled throughout life. Among mudpuppies and waterdogs (genus Necturus), this species is medium-sized. All mudpuppies and waterdogs have bushy external gills, two gill slits, a laterally compressed tail, and four toes on front and hind feet. Adult Alabama waterdogs measure 10-13 cm snout to vent length (15-22 cm total length). The dorusm is reddish brown to nearly black. Some populations have spots on the dorsum. The venter lacks spots in all age classes. Tips of the toes are light colored. The body and head are flattened. Sexually mature males can be distinguished by the swollen cloaca and pair of enlarged cloacal papillae that project posteriorly. Hatchlings are mottled dorsally with a few light spots. In some populations, juveniles have light stripes on the head and back, similar to juveniles of N. maculosus. Juveniles have a dark eye stripe running from the nostril, through the eye to the gills. The stripe is retained in adults. (Neill 1963; Bart et al. 1997; Petranka 1998; Bailey and Moler 2003).
Sympatric with N. beyeri in some localities, but these species differ in body shape (flattened in N. alabamensis vs. near cylindrical in N. beyeri), ventral coloration (absence vs. presence of spots), and microhabitat use (shelter under rocks or debris, active on the bottom vs. living in burrows, and frequently active in the water column) (Neill. 1963; Bart et al. 1997).
The systematics of Necturus in general, and N. alabamensis in particular, have been quite problematic. Some authors have doubted that the Alabama waterdog is a separate species from the Gulf Coast waterdog (N. beyeri). Although they co-occur in some areas, these forms are apparently distinct in microhabitat preference, morphology, and with respect to genes (Neill 1963; Guttman et al. 1990; Bart et al. 1997). Populations of Necturus from the Coastal Plain have sometimes been assigned to this species, but they are now tentatively assigned to N. beyeri. (Bailey and Moler 2003).See Petranka (1998) and Bailey and Moler (2003)for further discussion.