Amphibians of North Carolina
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NC Records

Plethodon shermani - Red-legged Salamander

Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic Comments:
Species Comments: The Plethodon jordani complex is a group of closely related forms that mostly are found at higher elevations in the southern Appalachian Mountains. Because they are largely restricted to mid to higher elevations and are absent from valleys, they form a series of geographic isolates that have diverged from one another to varying degrees. Depending on geographic location, the adults may be unmarked, or have red cheeks, red legs, or brassy frosting on their backs. Members of this group were traditionally treated as a single, geographically variable species known as Jordan's Salamander (Plethodon jordani). Hairston (1950) recognized seven subspecies of P. jordani, but Highton (1962) rejected these because some characters do not vary concordantly among the recognized taxa. In later papers, Highton (1970, 1972) recognized 12 geographic isolates in southern populations and argued that recognizing subspecies would serve no useful purpose.

Molecular studies (Highton and Peabody 2000, Weisrock and Larson 2006) have since revealed the presence of seven major evolutionary lineages that are now recognized as separate species (P. amplus, P. cheoah, P. jordani (sensu stricto), P. meridianus, P. metcalfi, P. montanus, and P. shermani). Some of the recognized species within the Plethodon jordani complex show both historical and current-day genetic influence from one or more other species, and mating studies indicate that none of these forms are completely reproductive isolated due to mating barriers (Reagan 1992, Wiens et al. 2006). Where adjoining forms come into contact, they generally tend to hybridize to varying degrees. In addition, certain members of this group also hybridize with members of the Plethodon glutinosus complex (Weisrock et al. 2005, Wiens et al. 2006). Discordance between mtDNA and nuclear data are well-documented (Weisrock and Larson 2006) and reflect various levels of gene-mixing. This not only is occurring today, but likely occurred historically during the Pleistocene as ranges expanded during glacial periods and previously isolated forms came into contact. Here, we recognize all of these species and discuss issues with hybridization in the individual species accounts.
Identification
Description: Plethodon shermani is a relatively large Plethodon that is dark gray to bluish black above with a grayish venter. The tail of adults is slightly longer than the body and is rounded in cross-section. This species occurs as four geographic isolates on regional mountain ranges. On three of these, the legs have orangish-red to reddish pigmentation on the dorsal surface that typically covers most of the limbs except for the most distal portions. In the Unicoi Mountains, specimens usually lack red coloration on the legs and have lateral white to yellow spots (Highton and Peabody 2000, Weisrock et al. 2005). Sexually-active males have conspicuous, rounded mental glands. The adults vary from about 9-18 cm TL and there are usually 16 costal grooves. This species is easily identified in most areas by its red legs that contrasts with a gray body. Plethodon cheoah is indistinguishable, but is restricted to Cheaoh Bald and does not co-occur with Plethodon shermani.

The Red-legged Salamander is a high-elevation species that has isolated populations on Standing Indian Mountain, Wayah Bald, Tusquitee Bald, and in the Unicoi Mountains. It extensively hybridizes with several other large Plethodon species, including P. teyahalee, P. chattahoochee, and P. aureolus (Highton and Peabody 2000). Weisrock et al. (2005) examined mtDNA variation and found mtDNA haplotypes of P. shermani in four divergent clades that were intermixed with numerous species of the P. glutinosus complex. These patterns differed from those based on allozyme variation and further confirms that widespread recent and historical hybridization has occurred between P. shermani and several other Plethodon species.

Hybridization with other species generally occurs where relatively high-elevational populations of P. shermani meet other Plethodon species that are found at lower elevations. Well-defined hybrid zones are often evident where there is contact with other species near the periphery of the P. shermani isolates. Hybrids typically show intermediate traits. On Standing Indian Mountain and Wayah Bald, for example, hybrids between P. shermani and P. teyahalee commonly have reduced reddish pigmentation on the legs and relatively small amounts of lateral white spotting on the body. Areas between the Standing Indian, Tusquitee, and Wayah isolates are considered by many to be hybrid swarms. MtDNA analyses of populations in the Unicoi Mountains on the Tennessee border show evidence of historical or current hybridize with several other Plethodon species, including both P. aureolus and P. teyahalee (Weisrock et al. 2005). Pure P. shermani in this isolate (if they exist) can be difficult to distinguish from these since specimens of P. shermani tend to have no red on the legs, varying amount of white spotting on the sides, and no dorsal spotting (Niemiller and Reynolds 2011). So, expect variation in phenotypes from the standard red-legged forms of P. shermani due to the widespread mixing of genes from other species.
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Observation Methods: The adults forage outside of cover at night and can be found underneath logs and other cover objects during the day.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: P. shermani is a high-elevation species that has isolated populations on Standing Indian Mountain, Wayah Bald, Tusquitee Bald, and in the Unicoi Mountains. See comments above concerning hybridization and hybrid swarms.
Distribution Reference: Highton and Peabody (2000); Weisrock et al. (2005)
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: The Red-legged Salamander is found in mesic hardwood forests that occur at mid- to higher elevations in the southern Appalachians. Local populations reach their highest densities in mature forest stands with deep layers of leaf litter and large amounts of bark and coarse woody debris.
See also Habitat Account for General Montane Mesic Forests
Life History and Autecology
Breeding and Courtship: Arnold (1976) observed courtship of members of the P. jordani complex from four geographic isolates and found them all to be indistinguishable. The following is a summary of the major aspects of breeding and courtship as summarized by Petranka (1998). These presumably apply to all seven recognized species in this complex.

When courting, a male approaches a female and begins nudging, nosing, or tapping her with his snout. He then places his mental gland and nasolabial grooves in contact with the back, sides, or tail of the female and engages in a 'foot dance' in which the limbs are raised and lowered off the substrate one at a time. The male eventually moves forward and presses his mental gland along the side of the female's head and over her nasolabial grooves. The male then turns his head under the female's chin and lifts. Next, the male circles under the female's chin and laterally undulates his tail as he passes. If the female is responsive, she places her chin on his tail and moves forward to the base of the tail. The pair then engages in a tail-straddle walk that may last for 1 hour. During the walk the male may turn and slap the female across her nasolabial region with his mental gland. This introduces pheromones via the nasolabial grooves.

The male eventually stops moving and begins a series of lateral rocking movements of his sacrum. The female begins a series of synchronous lateral head movements counter to the lateral movements of the sacral region of the male. The male then presses his vent to the substratum and deposits a spermatophore. Immediately after, he flexes the tail to one side and leads the female forward. She stops when her vent is over the spermatophore, then lowers her sacrum and picks up the sperm cap. During this process the male arches the sacral region and does a series of pushup motions with the rear limbs. The pair usually splits up and terminates courtship shortly after spermatophore deposition, even if the female is unsuccessful in picking up the spermatophore.

The adults of the P. jordani complex court from July through early October based on field observations. A female normally lays a clutch of eggs every other year, and only mates during the year when she nest. Arnold (1976) noted that males will not aggressively court sexually mature females that have small ovarian eggs, but will actively court females with large ovarian eggs.
Reproductive Mode: The nesting biology is undocumented, but the females presumably nest underground during the summer months and guard their clutch of eggs through hatching.
Aquatic Life History: This is a fully terrestrial species that lacks an aquatic larval stage.
Terrestrial Life History: During the warmer months of the year the juveniles and adults remain beneath cover objects or in underground burrows during the day and emerge with the onset of darkness. They forage at night on leaf litter and sometimes climb short distances above the litter layer on tree trunks and low vegetation. Whitaker and Rubin (1971) found a wide variety of prey in 435 specimens that they examined from the Nantahala Mountains. The 10 most important prey by volume were ants, spiders, lepidopteran larvae, beetle larvae, collembolans, millipedes, centipedes, mites, snails, and dipteran larvae. The dietary items included over 60 families of insects.

Lewis et al. (2014) compared the diets of specimens that were climbing on vegetation to those on the leaf litter. Individuals consumed a wide diversity of prey, with ants, beetles, oribatid mites and millipedes comprising most of the diet. Salamanders on the ground and on vegetation did not significantly differ in their use of these general prey categories, and climbing individuals had prey that was mostly associated with leaf litter, suggesting that they did not forage much after climbing. Climbing may have other functions that are rather poorly understood, such as avoiding ground predators or sensing mates using olfactory cues.
General Ecology
Population Ecology: Populations of members of the P. jordani complex generally tend to be stable through time and likely reflect density-dependent regulation associated with territoriality (Hairston 1987). The adults have small home ranges and will aggressively defend space that contains food or potential mates from intruders (Petranka 1998). Selby et al. (1996) found that levels of aggression in a Standing Indian population increased with SVL, and that adult males were about four times more aggressive than juveniles. Overall, levels of aggression were similar for individuals from two populations of P. shermani and four populations of P. montanus.
Community Ecology: The Red-legged Salamander is often one of many salamander species that coexists in forested habitats near streams. Most are opportunistic predators on invertebrates, while others such as the Spring Salamander commonly prey on other salamanders. Competitive and predatory interactions of P. shermani with other community members are poorly documented and need additional study.

Plethodon shermani and P. teyahalee segregate elevationally in the Nantahala Mountains and hybridize in contact zones. Drummond (2015) conducted laboratory trials to determine how P. shermani, P. teyahalee, and their hybrids interact and found that P. shermani was far more aggressive, with more than six times the number of aggressive behaviors as P. teyahalee, and with more than two times the number of aggressive actions as hybrids. His data suggest that P. teyahalee is restricted to lower elevations due to competitive exclusion by P. shermani.
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S3S4
Global Rank: G3
Status in North Carolina: W2
Environmental Threats: This and other eastern salamanders are sensitive to intensive timbering. Local populations of members of the P. jordani complex may decline to near zero following the clearcutting of mature hardwood forests (Ash 1988, Petranka et al. 1993, 1994). Less intensive harvesting practices that leave the basic structure of the forest intact would benefit this and other salamander species in southern Appalachian forests. Hairston and Wiley (1993) monitored members of the P. jordani complex and their hybrids in mature forests in western North Carolina and found no evidence of long-term population declines over a 15-year period.
Status Comments: Local populations are sensitive to intensive timber practices but generally recover within a few decades. This species is locally abundant throughout its range and appear to be in minimal need of protection.
Stewardship: Local populations are best maintained by having large tracts of mature, mesic deciduous forest.

Photo Gallery for Plethodon shermani - Red-legged Salamander

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Recorded by: David George
Macon Co.		Recorded by: Jim Petranka
Macon Co.
Recorded by: Jim Petranka
Macon Co.