Amphibians of North Carolina
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NC Records

Desmognathus auriculatus - Southern Dusky Salamander


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Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae Other Common Name(s): Southern Dusky Salamander
Taxonomic Comments: Herpetologists have traditionally treated populations of a medium-sized Desmognathus that occurs on the Coastal Plain from southeastern Virginia to eastern Texas as the Southern Dusky Salamander, D. auriculatus. Individuals are variable, but typically have a laterally flattened tail, a blackish dorsum, two rows of light spots along each side of the body, and a blackish, speckled venter. Molecular studies have since provided evidence that these forms consist of multiple independent lineages and constitute a poorly resolved species complex (see Beamer and Lamb 2020 and Pyron et al. 2020). Beamer and Lamb (2008) found that the Atlantic Coastal Plain populations of putative D. auriculatus comprised five lineages. In addition, Beamer and Lamb (2020) found that populations that are currently referred to as D. auriculatus include two clades that are more genetically similar to members of the D. fuscus complex than to a third D. auriculatus clade. Additional populations in eastern Texas (now treated as D. conanti; Hibbitts et al. 2015) and near Mobile, Alabama (Beamer and Lamb 2020) also appear to be distinct from other geographic groups. Means et al. (2017) treated a Gulf Coastal Plain form that occurs in Mississippi and Louisiana as a separate species, D. valentinei. They also redescribed D. auriculatus and restricted this species to populations in northern Florida and southern Georgia.

Collectively, these data suggest that D. auriculatus as traditionally recognized will likely be split into multiple species. All populations in North Carolina -- along with populations in northeastern South Carolina that extend to around the Great Pee Dee River -- are members of Clade C of Beamer and Lamb (2020). Since D. auriculatus was originally described from Georgia, and Means et al. (2017) only applied the name to populations in northern Florida and southern Georgia, North Carolina populations may eventually be treated as members of a separate species and given a different scientific name. Until additional taxonomic revisions are made, we continue to treat populations that are found from Virginia to northern Florida as a single species (D. auriculatus sensu lato).
Species Comments:
Identification
Description: Desmognathus auriculatus (sensu lato) is a medium-sized dusky salamander that has a dark brown or blackish dorsum and sides. Many specimens have one or two rows of tiny whitish or reddish-orange spots that extend along each side of the body and often onto the tail. A third row of lateral spots is often present near the junction of the side and venter. The venter varies from grayish brown to black and is speckled with whitish flecks. Varying amounts of reddish pigmentation are often present along the top of the basal half of the tail, which is laterally compressed and blade-like on the distal half. The toe tips lack cornifications and there is an average of 14 costal grooves (Beane et al. 2010, Petranka 1998). The adults vary from about 8-16 cm TL.

The larvae are dusky brown to black and have darkly pigmented, blackish gills that are bushier and darker colored than those of other sympatric Desmognathus. The body is uniformly black above and has three pronounced rows of lighter colored dots down each side of the body (Means 2015). The upper two rows lie close together dorsolaterally on the body, but diverge on the tail so that the uppermost row disappears about halfway down the tail. The lower row becomes mid-lateral and quite pronounced. The lowermost row on the body is also prominent and extends only from the armpit to the groin.
Field Guide Descriptions: Beane et al., 2010
Online Photos:    Google
Observation Methods: Specimens can be collected by searching leaf litter, woody debris, or sphagnum mats and other cover immediately next to the water's edge.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: As recognized here Desmognathus auriculatus (sensu lato) ranges from southeastern Virginia southward along the Coastal Plain to northern and central Florida. A geographic isolate is also present in the mountains of southwestern Virginia. In North Carolina this species is widely distributed throughout most of the Coastal Plain.
Distribution Reference: Beamer and Lamb (2008, 2020); Beane et al. (2010)
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: The Southern Dusky Salamander occurs in forested floodplains in the Coastal Plain as well as ravine heads in the Florida Panhandle. Throughout most of the range the juveniles and adults reside under leaf litter, woody surface debris, sphagnum mats, and in underground cavities in peaty soils. They prefer microhabitats with mucky soils or decomposing peat near the edges of swamps, sloughs, sluggish streams, or other stagnant or slow-moving waters. Individuals can also be found in sphagnum moss mats along the edges of lakes or other wetlands. Eggs are laid terrestrially under moss clumps, in decaying peat, or other shelter that keeps them cool and moist. There is an aquatic larval stage, so the eggs are typically placed very close to the water's edge (Beane et al. 2010, Means 2015, Petranka 1998).

Biotic Relationships: This species often shares habitats with a variety of other amphibians and reptiles (Bruce 2015), but ecological interactions with these species are largely undocumented.
See also Habitat Account for Coastal Plain Wet-Hydric Forests
Life History and Autecology
Breeding and Courtship: Verrell (1997) described courtship behavior for specimens collected from near the Savannah River Site in South Carolina. In paired laboratory encounters, males spend much time orienting to and stimulating the female by engaging in nudging and rubbing behavior. A approaching male will often butterfly a female, which involves moving his forelegs in a motion that resembles the butterfly stroke of a swimmer. Males nudge and rub the body and head of females with their snouts, and also pull the snout and teeth across the back of the female. This abrades the skin and presumably introduces pheromones from the male's mental glands into the female's circulatory system.

A courting male will eventually slide his body under the female's chin until it rests on the base of his undulating tail. He then arches his body backwards in a C-shaped position, from which the pair often engages in a circular waltz of sorts. The male eventually forcefully snaps his head against the female's dorsum, which lacerates the skin and introduces additional pheromones into the circulatory system. This causes the female to move away. The male then quickly returns to the female and the pair engages in a tail-straddle walk where the pair moves forward after the female straddles the male's undulating tail with her forelegs. The male eventually deposits a spermatophore, then leads the female forward. She picks the sperm cap off with her cloacal lips, and the pair separates shortly thereafter.
Reproductive Mode: Females lay grape-like clusters of eggs beneath woody surface cover, sphagnum mats, and in cavities excavated in peat.They guard their eggs through hatching. Wood and Clarke (1955) found a guarding female that had consumed four eggs, but it is uncertain if the embryos were dead or alive when consumed.

Based on limited nesting records, the nesting season appears to be rather prolonged and extends from late spring through early fall (Petranka 1998). Neill and Rose (1949) estimated that females begin nesting as early as late April or early May at a site in southern Georgia based on observations of hatchlings and a female with late-term embryos. Robertson and Tyson (1950) found six clutches with late-term embryos and attending females on 5 September in North Carolina. The eggs were in globular masses in cavities within rotted cypress logs and stumps near the water's edge and contained from 14-20 eggs per clutch. Eaton (1953) found a female with two eggs and 15 young in late October from the same area, while Wood and Clarke (1955) found a nest with 26 eggs on 27 August beneath a cypress limb in southeastern Virginia. Goin (1951) discovered 10 clutches at hatching stages on 28 October in Florida beneath sphagnum mosses. The number of eggs per clutch varied from 9-19. Other nests with their brooding mothers have been found in Florida between 12 September and 14 November that contained 6-16 eggs.
Aquatic Life History: Females nest close to the water's edge and the hatchlings presumably move a short distance to nearby bodies of water where they feed on invertebrates. The larvae are typically found in sluggish bodies of water such as small pools, sloughs, swamps, and sluggish streams. They frequently live near the water's edge in leaf litter or other cover (Means 2015). Hatching in Florida occurs in the fall or early winter, and the larval period is thought to last no more than 8-9 months (Means 2015). Very little is known about the length of the larval period elsewhere.
Terrestrial Life History: After metamorphosing, the juveniles and adults live in the immediate vicinity of bodies of water. They have frequently been collected by raking leaf litter along the margins of pools or sloughs. The adults are also excellent burrowers and will often burrow into peat or other substrates to avoid drying conditions (Means 2015). Like other Desmognathus, individuals appear to be generalist, opportunistic predators. Florida specimens examined by Carr (1940) consumed beetle larvae, earthworms, tabanid flies, lycopsid spiders, and craneflies. Most males in central Florida become mature when > 32 mm SVL, but the length of the juvenile stage is not known precisely (Petranka 1998).
General Ecology
Adverse Environmental Impacts
Habitat Loss: The widespread destruction and degradation of bottomland forests and associated wetlands in the southeastern Coastal Plain that has occurred since European colonization (e.g., Haynes and Egan 2004) has undoubtedly eliminated numerous local populations of this and numerous other amphibians.
Status in North Carolina
NHP State Rank: S5
Global Rank: G4
Environmental Threats: Bottomland forests once cover much of the low-lying areas and river floodplains of the southeastern Coastal Plain prior to European and provided essential habitats for this and many other amphibians. Millions of acres have subsequently been destroyed, particularly during the last century when much was converted to agricultural fields (Haynes and Egan 2004, Smith et al. 2001, Turner et al. 1981). North Carolina has also suffered extensive losses, with hundreds of thousands of acres of the original forests and their associated wetlands destroyed or severely impaired (e.g., Carle 2011, Cashin et al. 1992, Turner et al. 1981). Many of the forests that are left are fragmented and degraded. The continued loss and degradation of bottomland forests and their associated wetlands is the greatest threat to this species.
Status Comments: Desmognathus auriculatus (sensu lato) appears to have undergone major declines during the last few decades (reviewed by Means 2015). For example, Means and Travis (2007) searched 63 ravines in the Florida panhandle where the species was recorded as being the most abundant salamander in the 1970s. They could not find a single specimen during a resurvey of these sites. Similarly, from 39 historic sites and 25 additional sites that appeared suitable for the species in Alabama and Georgia, Graham et al. (2010) found only a few individuals at only two sites. The status of populations outside of Florida and Georgia are poorly documented. Beamer and Lamb (2020) collected specimens from many sites in South Carolina and North Carolina for their molecular studies, suggesting that populations in the Carolinas have not declined precipitously.
Stewardship: Bottomland hardwood forests offer optimal habitats for this species. The maintenance of forest buffers around small streams, sloughs, swamps, and marshes will help maintain high quality habitat for this and many other vertebrates in southeastern Coastal Plain communities.