Description
Necturus mounti is a neotenic species of aquatic salamander with adults reaching a standard length of up to 116 mm for males and 110 mm for females. Average male snout-vent length is 108.4mm and average female snout-vent length is 94.8 mm. Males reach sizes that average 13.6 mm longer in standard length than females. This species is identified as a member of the family Proteidae by retention of external gills in adults, and the presence of four robust limbs with four toes on the hind limbs. Typically, seventeen costal grooves are present (range of 16-17). Reproductive males can be distinguished from adult females by the presence of a swollen cloaca, a cloacal lining of finger-like projections, and a spur-like tip on each side of the posterior end of the cloacal opening (Guyer et al. 2020).

Larvae of Escambia Waterdogs lack the dark middorsal or dorsolateral stripes of larvae of N. alabamensis, N. lewisi, and N. maculosus. Similarly, larvae of Escambia Waterdogs lack the white spotting of larvae of N. beyeri. Adults of Escambia Waterdogs typically possess dark spots that are not typically present in adults of N. punctatus. Adults and larvae of Escambia Waterdogs are most difficult to distinguish from those of Apalachicola Waterdogs (N. moleri). However, adults of Escambia Waterdogs typically have a wide, spotless belly while adults of Apalachicola Waterdogs have dark spotting that invades the ventrolateral area (Guyer et al. 2020).

In life, the dorsum and sides of adults are pinkish gray with numerous small dark purple or black spots. The size of the dark spots typically is about the same size as the eyes. In preservative, the head is a dark slate brown. The dorsal ground color is a uniform dark grey brown that retain the dark spots. The tail is similar in coloration and patterning as the dorsum as are the lateral surfaces of the body. The lateral coloration abruptly changes to an immaculate white at the midventer with a scalloped edge transition zone. The chin is also immaculate white (Guyer et al. 2020). Larvae of Escambia Waterdogs are uniform pinkish gray, lacking small white spots at the smallest sizes. As they grow, dark spots appear and become prominent (Guyer et al. 2020).

Typically, seventeen costal grooves are present (range of 16 - 17). Although most individuals have patterning as described above, approximately 10% lack any spots and 10% have large spots. Similarly, a small percentage of specimens have spots along the mandibles or ventrolateral spots on the belly. Reproductive males can be distinguished from adult females by the presence of a swollen cloaca, a cloacal lining of finger-like projections, and a spur-like tip on each side of the posterior end of the cloacal opening (Guyer et al. 2020).

Distribution and Habitat

Country distribution from AmphibiaWeb's database: United States

U.S. state distribution from AmphibiaWeb's database: Alabama, Florida

View distribution map in BerkeleyMapper.

Necturus mounti can be found in Alabama and the western Panhandle of Florida of the United States. More specifically, they can be found in the Blackwater, Escambia (Conecuh in Alabama), Perdido, and Yellow River drainages. The type locality is Camp Creek where it is crossed by Forest Service Road 332, Covington County, Alabama (Guyer et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
Escambia Waterdogs occur in slow-moving streams where they are most frequently detected in accumulated piles of submerged leaf litter. These salamanders may be collected by dipnets, minnow traps (Brenes and Ford 2006), or by use of litter bags (Lamb and Qualls 2013). Adults appear to migrate to leaf packs, but juveniles stay in leaf packs until adulthood (Guyer et al. 2020).

Adult Escambia Waterdogs are most likely to be detected in winter months (November – January), when mating occurs. Fertilization occurs via transfer of a spermatophore deposited by a male to a female who picks it up with her cloacal lips. Fertilized eggs are retained within a female’s uterus until the clutch is deposited, likely in April or May. Nests are thought to be placed in leaf packs. After hatching, larvae can be sampled from leaf packs, eventually reaching adult size in 4 - 6 years (Petranka 1998, Guyer et al. 2020).

Larvae and adults likely eat isopods, midges, mayflies, and caddisflies. Predators likely include fishes, aquatic snakes, and crabs (Petranka 1998).

Escambia Waterdogs may be infested with acanthocephalan parasites, for which Waterdogs are a definitive host (Bart and Holzenthal 1985).

Necturus mounti can be found in leaf packs with Siren intermedia, Desmognathus conanti, Ichthyomyzon gagei, dragonfly naiads, and small crayfish (Guyer et al. 2020).

Trends and Threats
While the species appears common at the type locality (Guyer et al. 2020), Petranka (1998) speculates that numbers of Escambia Waterdogs likely have been reduced due to siltation and pollution.

Possible reasons for amphibian decline

General habitat alteration and loss
Local pesticides, fertilizers, and pollutants

Comments
The species authority is: Guyer, C., Murray, C., Bart, H.L., Crother, B.I., Chabarria, R.E., Bailey, M.A., Dunn, K. (2020). "Colour and size reveal hidden diversity of Necturus (Caudata: Proteidae) from the Gulf Coastal Plain of the United States." Journal of Natural History, 54(1-4), 15-41.

Based on Bayesian Inference of ND2 mtDNA, N. mounti is the species is sister to all other Necturus of the Gulf Coastal Plain (Chabarria et al. 2017, Guyer et al. 2020).

The specific epithet, “mounti” is in honor of Robert H. Mount, a former curator of Herpetology at Auburn University, who pointed out the taxonomic challenges of Alabaman Waterdogs (Guyer et al. 2020).

References

Bart, H.L., Jr., Holzenthal R.W. (1985). ''Feeding ecology of Necturus beyeri in Louisiana.'' Journal of Herpetology, 19(3), 402-410. [link]

Brenes, R., Ford N.B. (2006). ''Seasonality and movements of the Gulf Coast Waterdog (Necturus beyeri) in eastern Texas.'' Southwestern Naturalist , 51(2), 152-156. [link]

Chabarria R.E., Murray C.M., Moler P.E., Bart H.L., Crother B.I., Guyer C. (2017). ''Evolutionary insights into the North American Necturus beyeri complex (Amphibia: Caudata) based on molecular genetic and morphological analysis.'' J Zool Syst Evol Res., 56(3), 352-363. [link]

Guyer, C., Murray, C., Bart, H.L., Crother, B.I., Chabarria, R.E., Bailey, M.A., Dunn, K. (2020). ''Colour and size reveal hidden diversity of Necturus (Caudata: Proteidae) from the Gulf Coastal Plain of the United States.'' Journal of Natural History, 54(1-4), 15-41. [link]

Lamb, J.Y., Qualls, C.P. (2013). ''Necturus beyeri (Gulf Coast Waterdog): Detection by leaf litter bag.'' Herpetological Review, 44(3), 491. [link]

Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington D.C. and London.

Species Account Citation: AmphibiaWeb 2020 Necturus mounti: Escambia Waterdog <https://amphibiaweb.org/species/9178> University of California, Berkeley, CA, USA. Accessed Nov 21, 2024.

Citation: AmphibiaWeb. 2024. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 21 Nov 2024.

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