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. Necturus beyeri is brownish dorsally and lighter brown ventrally. Numerous dark brown to blacks spots can be seen on the dorsum, sides, and venter. Adults are 16-22 cm total length. Sexually mature males can be distinguished by the swollen cloaca and pair of enlarged cloacal papillae that project posteriorly. Hatchlings are mottled with a few light spots dorsally. Hatchling size is 13-16 mm snout to vent length (Shoop 1965). Juveniles are spotted and do not have stripes as seen in N. maculosus. Description primarily from Petranka (1998).
Sympatric with N. alabamensis in some localities, but these species differ in body shape (near cylindrical in N. beyeri vs. flattened in N. alabamensis), ventral coloration (presence vs. absence of spots), and microhabitat use (living in streambank burrows, and frequently active in the water column vs. shelter under rocks or debris, active on the bottom) (Neill. 1963; Bart et al. 1997).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: United States
U.S. state distribution from AmphibiaWeb's database: Alabama, Florida, Georgia, Louisiana, Mississippi
The range is composed of two disjunct portions. Populations occur from eastern Texas to central Louisiana, and from southeastern Louisiana to central Mississippi. Found in medium to large streams. Logjams and leafy detritus are important habitat for adults and young (Petranka 1998 and references therein).
Life History, Abundance, Activity, and Special Behaviors
Little is known about the life history of this species. Some features may be similar to other species of Necturus. Courtship activity has not been observed. Fertilization is internal by means of a spermatophore (Petranka 1998; Sever and Bart 1996). Mating likely begins in late autumn or winter, and possibly extends over a few months. One female was found containing a spermatophore in late December. In one population that was studied in detail, oviposition sites were under large boards, railroad ties and logs embedded in sandy sections of the stream. Eggs are attached singly to the undersides of cover objects (Shoop 1965). Oviposition occurs in late April to May. Nests have been found with and without females so it is not clear if females attend their eegs. Average clutch size is around 30 (Shoop 1965; Sever and Bart 1996). Hatching occurs about 2 months after oviposition (Shoop 1965).
Diet items include crayfish, isopods, amphipods, mayflies, dragonflies and sphaeriid clams. Predators are not known, but likely include fish and crayfish (Petranka 1998). Necturus beyeri often occupies burrows in streambanks, and individuals frequently swim in the water column when they are active (Neill 1963). Mudpuppies and waterdogs are nearly inactive in the summer, and individuals are rarely found (Petranka 1998). Animals caught in the autumn may be quite lean compared with their condition in the winter and spring when they are in reproductive readiness (Bart et al. 1997).
Trends and Threats
Pollution and siltation of streams and rivers are likely to be threats to waterdog populations (Petranka 1998).
Relation to Humans
Mudpuppies and waterdogs are sometimes seen in the pet trade.
The systematics of Necturus in general, and N. beyeri in particular have been problematic. Some authors have doubted that the Alabama waterdog (N. alabamensis) is a separate species from the Gulf Coast waterdog. 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). See Petranka (1998) for discussion.Necturus beyeri, N. alabamensis, and N. maculosus are relatively closely related (Guttman et al. 1990).
Bart, H. L., Jr., Bailey, M. A., Ashton, R. E., Jr., and Moler, P. E. (1997). ''Taxonomic and nomenclatural status of the Upper Black Warrior River Waterdog.'' Journal of Herpetology, 31, 192-201.
Guttman, S. I., Weigt, L. A., Moler, P. E., Ashton, R. E., Jr., Mansell, B. W. and Peavy, J. (1990). ''An electrophoretic analysis of Necturus form the southeastern United States.'' Journal of Herpetology, 24(2), 163-175.
Neill, W. T. (1963). "Notes on the Alabama waterdog, Necturus alabamensis Viosca." Herpetologica, 19, 166-174.
Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington and London.
Sever, D. M., and Bart, H. L., Jr. (1996). ''Ultrastructure of the spermathecae of Necturus beyeri (Amphibia: Proteidae) in relation to its breeding season.'' Copeia, 1996(4), 927-937.
Shoop, C. R. (1965). "Aspects of reproduction in Louisiana Necturus populations." American Midland Naturalist, 74, 357-367.
Written by Meredith J. Mahoney (molge AT yahoo.com), Museum of Vertebrate Zoology
First submitted 2000-07-26
Edited by M. J. Mahoney (2001-05-09)
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