Amphibians of North Carolina
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NC Records

Desmognathus valtos Pyron and Beamer, 2022 - Carolina Swamp Dusky Salamander


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Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae Author: Pyron and Beamer, 2022
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 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.

Populations in central Louisiana, northern Louisiana and extreme eastern Texas were recently described as D. catahoula (Pyron and Beamer, 2023a), while Means et al. (2017) treated a Gulf Coastal Plain form that occurs in southern Louisiana, Mississippi and Alabama as a separate species, D. valentinei. Populations of D. valentinei from southeastern Mississippi and southwestern Alabama were subsequently described as D. pascagoula by Pyron et al. (2022a). The remaining populations from southern Alabama to southeastern Virginia form two mito-nuclear candidate species, with one occurs in south-central Alabama, northern and peninsular Florida, and southern Georgia (D. auriculatus sensu stricto), and another from southeastern Georgia northward to North Carolina and vicinity (Pyron et al. 2022c). The northern group was subsequently described as a new species, D. valtos, by Pyron and Beamer (2022b).
Species Comments:
Identification
Description: Desmognathus valtos is a medium-sized dusky salamander (17.2–62.4 mm SVL for transformed specimens) that has a dark greenish-gray ground color and orangish wash on the dorsal surfaces. Smaller individuals may have visible remnants of orangish or reddish paired larval spots on the dorsum, but these are quickly lost after metamorphosis as the dorsum darkens with age (Pyron and Beamer, 2022b). The line between the eye and angle of the jaw is often bright yellowish-orange or red, and there is very little differentiation between dorsal and lateral color patterns as is commonly the case in most Desmognathus species. The tail is flattened at the end and can comprise up to 106% of the SVL. It is thick and girthy, has a weak keel, and usually has a yellowish or orangish stripe with indistinct margins on the dorsal surface. Many specimens have one or two rows of tiny whitish, yellowish, orangish, or reddish porthole markings or 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 ventral color pattern is relatively bright and granular, and consists of an interspersed reticulation of brownish, yellowish and whitish speckling. 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 Desmognathus. The body is uniformly black above and has rows of lighter colored dots down each side of the body.
Field Guide Descriptions: Beane et al., 2010.
Online Photos:    Google   iNaturalist
Observation Methods: Specimens can be collected by searching leaf litter, woody debris, sphagnum mats and other cover immediately next to the water's edge.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: Desmognathus valtos ranges from southeastern Virginia southward along the Coastal Plain to North Carolina, South Carolina and adjoining coastal counties of Georgia, to as far south as Liberty Co., Georgia. In North Carolina, this species occurs throughout the Coastal Plain.

Distribution Reference: Beane et al. (2010); Pyron and Beamer (2022b).
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: The Carolina Swamp Dusky Salamander is strongly associated with forested floodplains in the Coastal Plain. Specimens have been found in swamps, sloughs, mud-bottomed pools in floodplains, springs, and slow-moving muddy streams. 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. The eggs are laid on land 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.
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 in Virginia that had consumed four eggs, but it is uncertain if the embryos were dead or alive when consumed. Based on limited nesting records, the egg-laying season is lengthy, but primarily confined to the summer months. 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.
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. Very little is known about the length of the larval period or other aspects of the larval stage.
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. Like other Desmognathus, individuals appear to be generalist, opportunistic predators.
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 many other amphibians.
Status in North Carolina
NHP State Rank: [S5]
Global Rank: GNR
Environmental Threats: Bottomland forests once cover much of the low-lying areas and river floodplains of the southeastern Coastal Plain prior to European colonization 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 as traditionally known was recently split into several species, with North Carolina populations now named D. valtos, and more southern populations in Georgia and Florida as D. auriculatus. The latter 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 not as well known. Beamer and Lamb (2020) collected specimens of D. valtos from many sites in South Carolina and North Carolina for their molecular studies, and records from iNaturalist suggest that populations in the Carolinas have not declined precipitously as seen in D. auriculatus.
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.

Photo Gallery for Desmognathus valtos - Carolina Swamp Dusky Salamander

2 photos are shown.

Recorded by: Kevin Metcalf
Craven Co.
Comment: Creative Commons: iNaturalist https://creativecommons.org/licenses/by-nc/4.0/		Recorded by: Robby Deans
Beaufort Co.
Comment: Creative Commons: iNaturalist https://creativecommons.org/licenses/by-nc/4.0/