Amphibians of North Carolina
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Plethodontidae Members:
NC Records

Plethodon meridianus - South Mountain Gray-cheeked Salamander

Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic 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.
Species Comments:
Identification
Description: Plethodon meridianus is a cryptic species within the P. jordani complex. It -- along with Plethodon amplus, P. metcalfi and P. montanus -- comprise a group of closely related species that have gray cheeks and are essentially indistinguishable from one another based on external morphology and coloration. The mtDNA haplotypes from these four species do not form monophyletic groups corresponding to each species (Weisrock and Larson 2006), and the structure of mtDNA variation has likely been influenced by gene flow between previously diverged populations. Nonetheless, they continue to be recognized as four closely related species within the P. jordani complex. They are best identified by using either the collection locality, or a combination of collection locality and genetic markers in areas where the forms come into close geographic contact. All are relatively large Plethodon species that are dark gray to bluish black above with grayish venters. The tail of the adult is slightly longer than the body and is rounded in cross-section. Sexually-active males have conspicuous, rounded mental glands. The adults vary from 8.5-18.5 cm TL and there are usually 16 costal grooves. Plethodon meridianus is the only member of this complex in the South Mountains. It comes into close geographic contact with other gray-cheeked forms at the extreme western limits of its range (Heidler 2020). More refined molecular studies are needed in this region to determine the genetic composition of these forms in the contact zone.

This and other gray-cheeked species somewhat resemble melanistic forms of certain Desmognathus species with rounded tails (e.g., D. carolinensis; D. orestes), but differ in head shape, overall size, the size of the back legs relative to the front legs (larger in Desmognathus species), and the absence of a colored line from the eye to the angle of the jaw (usually evident in Desmognathus species). They are best identified by using either the collection locality, or a combination of collection locality and genetic markers in areas where the forms come into close geographic contact.
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AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: Plethodon meridianus is a narrow endemic that appears to be restricted to the South Mountains in Burke, Cleveland and Rutherford counties, and possibly in extreme southeastern McDowell County in North Carolina.
Distribution Reference: Highton and Peabody 2000, Weisrock and Larson 2006
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: This species inhabits mesic hardwood forests in the South Mountains of North Carolina.
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.

The adults of members of the P. jordani complex appear to court from July through early October based on field observations, but there are no observations to date for Plethodon meridianus. Females of the P. jordani complex normally lay a clutch of eggs every other year, and only mates during the year when they 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.

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.
Reproductive Mode: The nests of Plethodon meridianus have never been found, but gravid females of other members of the P. jordani complex move underground in late spring or early summer and presumably oviposit in deep underground recesses. Females of members of the P. jordani complex appear to oviposit in May in the southern Appalachians based on the presence or absence of gravid females in samples (Hairston 1983a). Hatching probably occurs in late summer or early autumn about 2-3 months after the eggs are deposited.
Terrestrial Life History: The adults can be found beneath cover objects during the day. They emerge at night when conditions are moist or rainy and forage on the ground surface. They presumably prey on small invertebrates like other Plethodon species, but dietary studies have not been conducted for this species. Almost all aspects of the life history of P. meridianus are poorly documented and a comprehensive life history study is needed.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S1
Global Rank: G2
Status in North Carolina: SR
Status Comments: Although it is a narrow endemic, Plethodon meridianus is locally common in the South Mountains and appears to be reasonably secure. Recently, the habitat of P. meridianus has been compromised due to residential development around the South Mountains State Park. The South Mountains State Park and the South Mountains Gamelands are the only state protected lands within the range of this species.
Stewardship: Sustainable populations of this and other woodland salamanders are best maintained by have large tracts of mature mesic forests.

Photo Gallery for Plethodon meridianus - South Mountain Gray-cheeked Salamander

2 photos are shown.

Recorded by: Max Ramey
Burke Co.		Recorded by: Todd Pierson
Rutherford Co.