Amphibians of North Carolina

Scientific Name:	Common Name:		Family (Alpha):

Plethodontidae Members:
Plethodon montanus - Northern 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 either 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 montanus is a cryptic species within the P. jordani complex. It -- along with Plethodon amplus, P. meridianus and P. metcalfi -- 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 adults 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.

These 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 (relatively 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.

Online Photos: Google iNaturalist

Observation Methods: Individuals are best observed the first few hours after dark when they are foraging on the forest floor. They can be found beneath bark, rotting logs, and other surface objects during the day.

AmphibiaWeb Account

Distribution in North Carolina

Distribution Comments: The range of Plethodon montanus extends from Max Patch in Madison County northeastward through extreme eastern Tennessee and western North Carolina to the Valley and Ridge Province of Virginia. Populations are patchily distributed on the higher mountain ranges within this general area.
Distribution Reference: Highton and Peabody, 2000
County Map: Clicking on a county returns the records for the species in that county.


GBIF Global Distribution

Key Habitat Requirements

Habitat: In North Carolina, Plethodon montanus lives in mesic hardwood forests and spruce-fir forests at mid to higher elevations in the Blue Ridge. Mature forests with a thick leaf litter layer and abundant coarse woody debris provide optimal habitats.

Biotic Relationships: This species co-occurs with other large Plethodon species such as P. yonahlossee and P. cylindraceus, but competitive interactions between these species are poorly documented.

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 (Petranka 1998). 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 nests of P. montanus have never been found. Gravid females with large ova move underground in late spring or early summer and presumably oviposit in deep underground recesses. Gravid females that were studied by Caruso and Rissler (2017) from five populations in western North Carolina had an average of 10 mature ova, and clutch size was independent of body size.

Aquatic Life History: This species is fully terrestrial and 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 burrows during the day and emerge with the onset of darkness. They forage at night on leaf litter except during dry conditions, and sometimes climb short distances above the litter layer onto tree trunks and low vegetation such as ferns. Whitaker and Rubin (1971) found a wide variety of prey in 337 specimens that they examined from near Grandfather Mountain. The 10 most important prey by volume were ants, spiders, lepidopteran larvae, beetle larvae, collembolans, millipedes, centipedes, mites, snails, and dipteran larvae. Dietary items included species from over 60 families of insects.

Individuals have small home ranges and appear to move very short distances during their lifetimes. Caruso and Rissler (2017) studied five populations along an elevational gradient in western North Carolina and repeatedly sampled plots to determine the spatial patterns of individuals. Spacing patterns suggest that the adults are territorial as is commonly seen in many Plethodon species. The distance moved between subsequent captures was typically less than two meters, (range = 0 – 14 meters) and home range sizes were small (mean = 1.3 m2). Males generally moved more and had larger home ranges than females and juveniles. In addition, the distance moved between captures was positively related to the size of the salamanders. The smallest female with large eggs was 48 mm SVL, while the smallest male showing secondary sex characteristics was 42 mm. However, patterns varied with elevation for males, with males at the highest elevation site not showing secondary sex characteristics until > 50 mm SVL. Individuals in high elevation populations tended to be larger, to grow slower, and to have higher survival, especially during the inactive season, compared to lower elevation populations. In all five populations, larger individuals had a higher probability of survival than smaller individuals. The estimated density of individuals in a streamside community in western North Carolina that was sampled by Petranka and Murray (2001) was 0.15 salamanders/m2.

General Ecology

Population Ecology: Populations of members of the P. jordani complex in mature forests 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) studied two populations of P. shermani and four populations of P. montanus and found that levels of aggression towards conspecifics were similar for all populations.

Community Ecology: Plethodon montanus is often one of many salamander species that coexist 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. montanus with other community members are poorly documented and need additional study.

Adverse Environmental Impacts

Status in North Carolina

NHP State Rank: S5

Global Rank: G4

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 P. jordani populations in mature forests in western North Carolina and found no evidence of long-term population declines over a 15-year period.

Plethodon montanus is adapted to cool, moist conditions and is generally found above 1000 m in elevation. Caruso et al. (2019) conducted reciprocal transplant experiments in western North Carolina which indicate that the lower elevational limits of this species is likely due to the hotter and drier conditions found at lower elevations in the mountains. This implies that climate change could potentially eliminate many lower elevation populations in the mountains if the climate warms substantially in the coming decades.

Status Comments: The Northern Gray-cheeked Salamander is widespread and locally abundant throughout its range and is in minimal need of protection.

Stewardship: Populations are best sustained by having large tracts of mature deciduous forest.

Photo Gallery for Plethodon montanus - Northern Gray-cheeked Salamander		9 photos are shown.
	Recorded by: M. Mabe Watauga Co.	Recorded by: M. Mabe Watauga Co.
	Recorded by: R. Spainhour Watauga Co.	Recorded by: B. Bockhahn Ashe Co.
	Recorded by: Owen McConnell Yancey Co.	Recorded by: Owen McConnell Yancey Co.
	Recorded by: Steve Hall and Bo Sullivan Ashe Co.	Recorded by: Steve Hall and Bo Sullivan Ashe Co.
	Recorded by: Jim Petranka Buncombe Co.

Plethodon montanus - Northern Gray-cheeked Salamander

Photo Gallery for Plethodon montanus - Northern Gray-cheeked Salamander

9 photos are shown.