Description
Necturus moleri is a neotenic species of aquatic salamander with adults reaching a standard length of up to 173 mm. Adult males average 126.4 mm and females average 102.3 mm in snout-vent length. Males reach sizes that average 24 mm longer in standard length than females. Tail length in male reaches a maximum of 73 mm and in female reaches up to 63 mm. 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, sixteen 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).

Adults of Apalachicola Waterdogs typically possess dark spots that are not typically present in adults of N. punctatus. Adults and larvae of Apalachicola Waterdogs are most difficult to distinguish from those of Escambia Waterdogs (N. mounti). 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 to light brown or pinkish-tan, with numerous small dark purple or black spots. Typically, the size of the dark spots is about the same size as the eyes, however, the patterning is more variable with a small proportion of specimens lacking spots (11% of specimens) and others having bold dark spots (4% of specimens). On the ventral surface, most individuals have dark spots on the chin and ventrolateral region of the dull white belly, but some individuals have spots across the whole surface (25% of specimens) and a much smaller proportion display immaculate white ventral surfaces (4% of specimens). At the mid-venter, the white belly gradually shifts to light brown at the sides of the body. In preservative, the dorsum is uniformly dark greyish brown and the top of the head has many small dark brown spots. From the dorsum, the skin lightens to off-white as it moves to the lateral surfaces of the body. The chin is light brown and may have dark brown spots along mandible at the chin. The gular fold is immaculate white and the anterior region of the ventral surface is light brown with a few dark spots. At the mid-venter the skin is shiny white with gradual darkening to a light smoky brown towards the lateral edges (Guyer et al. 2020).

Typically, sixteen costal grooves are present (range of 16 - 17). There are slight variations on dorsal ground color and a greater range of variation in the amount of spotting over the whole body (see above) than similar species. 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, Georgia

View distribution map in BerkeleyMapper.

Necturus moleri can be found in Alabama, Florida, and Georgia of the United States of America. More specifically, they are only found in the Apalachicola, Chipola, Choctawhatchee/Pea, Econfina, and Ochlockonee drainages. The type locality is Big Creek near Cottonwood, Houston County, Alabama (Guyer et al. 2020).

Life History, Abundance, Activity, and Special Behaviors
Apalachicola 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).

Adult Apalachicola 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).

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

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

Larva
Larvae of Apalachicola Waterdogs are uniform pinkish gray at the smallest sizes. As they grow, dark spots appear and become prominent (Guyer et al. 2020).

Larvae of Apalachicola Waterdogs lack the dark middorsal or dorsolateral stripes of larvae of N. alabamensis, N. lewisi, and N. maculosus. Similarly, larvae of Apalachicola Waterdogs lack the white spotting of larvae of N. beyeri.

Trends and Threats
Petranka (1998) speculates that numbers of Apalachicola 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 HL, Crother BI, Chabarria RE, Bailey MA, 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

Bayesian Inference of ND2 mtDNA indicate that N. moleri is sister to the clade composed of N. alabamensis, N. beyeri, and N. maculosus. When combined with this clade, the next most closely related species is N. mounti (Chabarria et al. 2017, Guyer et al. 2020).

Chromosome analysis of N. moleri indicate the species represents a transition from an ancestral state with reduced heterochromatism, found in N. lewsi and N. puncatus, to extensive heterochromatism, found in N. maculosus and the Western lineage of N. beyeri. However, more information is needed to support a reduced heterochromatic ancestral state hypothesis (Guyer et al. 2020).

The species epithet, “moleri” is in honor of Paul E. Moler for his contributions and advocation of herpetology in the southeastern United States. He specifically advocated for improving knowledge of Necturus species richness in the Gulf Coastal Plain (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]

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 2023 Necturus moleri: Apalachicola Waterdog <https://amphibiaweb.org/species/9177> 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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