Amphibians of North Carolina
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Plethodontidae Members:
NC Records

Aneides aeneus - Green Salamander

Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic Comments: Populations of a crevice-dwelling greenish salamander with a flattened body, long legs, and squared toe tips have traditionally been treated as a single species, the Green Salamander (Aneides aeneus). Suspicions were raised that a cryptic species complex might exists within this group when researchers examined morphological variation in chromosomes and documented substantial geographic variation among populations (Morescalchi 1975, Sessions and Kezer 1987; however, see Patton et al. 2019). Patton et al. (2019) conducted a comprehensive molecular analysis of populations from throughout the range and delineated four major evolutionary lineages. These include 1) a narrowly endemic group in the Hickory Nut Gorge of western North Carolina, 2) an adjoining group in the Blue Ridge Escarpment of North Carolina, northwestern South Carolina, and northeastern Georgia, 3) a northern Appalachian group that ranges from Maryland, Pennsylvania and West Virginia southwestward through eastern Kentucky to the Cumberland Plateau of central Tennessee, and 4) a southern Appalachian group that adjoins the latter group and ranges from central Tennessee to northwestern Georgia, northern Alabama, and northeastern Mississippi. Analyses of mtDNA indicate that these lineages are ancient, with the Hickory Nut Gorge lineage originating about 12 million years ago, and the youngest lineages originating about 5 million years ago. The authors recognized the Hickory Nut Gorge lineage as a separate species (A. caryaensis) based on molecular and morphological data. The remaining three groups were treated as evolutionarily significant units until the contact zone between the northern Appalachian and southern Appalachian group in Tennessee can be more thoroughly evaluated. These are treated here as A. aeneus (sensu stricto), with the understanding that all three lineages in this group may eventually be recognized as separate species.
Species Comments:
Identification
Description: The Green Salamander is a striking and readily identifiable species that is noteworthy for its greenish color, flattened body, long legs, and its expanded and squared toe tips that are adaptations for living in rock crevices. The dorsum of the body, tail, and limbs has a dark brownish-black ground color that is overlain with lichen-like patches of bright green to yellowish-green pigment. The venter is light colored and unmarked, and the base of each leg is often faintly washed in yellow. The adults are 8-14 cm TL and there are 14-15 costal grooves (Petranka 1998). The hatchlings are similar in color to the adults but have proportionately shorter tails and are less boldly marked with green. They vary from 18.5-23 mm TL.

Sexually-active males have a mental gland that is often yellowish orange, papillae on the anterior wall of the cloaca, enlarged jaw muscles, and elongated premaxillary and maxillary teeth that penetrate the upper lip. Mature females also have somewhat enlarged jaw muscles and protruding teeth, so these traits are not always reliable for sexing individuals in the field.

The Green Salamander closely resembles the Hickory Nut Gorge Green Salamander (A. caryaensis) but tends to be more boldly marked with lichen-like patches and has darker pigmentation on the lower sides of the body (Patton et al. 2019). The Hickory Nut Gorge Green Salamander is a micro-endemic species that is separated from the nearest known A. aeneus populations to the west by about 25 km. Thus, locality alone should be sufficient to identify specimens of both species.
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AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: The Green Salamander is mostly found in the Appalachian Mountains and consists of two major geographic groups. The largest group ranges from southwestern Pennsylvania, extreme western Maryland, and West Virginia southwestward through eastern Kentucky, extreme southwestern Virginia, and portions of east-central Tennessee to northwestern Georgia, northern Alabama, and northeastern Mississippi. The second group is disjunct and occurs in southwestern North Carolina and adjoining areas in northeastern Georgia and northwestern South Carolina. Smaller isolates have been found in southern Ohio, southern Indiana and central Tennessee. Populations in North Carolina are only known from the Blue Ridge Escarpment in Henderson, Transylvania, Jackson, and Macon counties (Beane et al. 2010, Patton et al. 2019, Wilson 2001).
Distribution Reference: Patton et al. (2019)
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: The Green Salamander inhabits cliffs and rock faces with deep crevices that provide shelter and nesting sites. Populations are most frequently encountered in sandstone, granite, and schist formations with deep, shaded, narrow crevices that are moist, but not dripping wet. They have also occasionally been found on quartzite and limestone cliffs and associated with the mouths of caves (Petranka 1998). In North Carolina individuals nest and overwinter in cliff faces and rock outcrops that are most often found in well-shaded habitats in relatively mature hardwood forests. Optimal rocky habitats have crevices that are moist but not dripping wet and that are relatively clear of soil, debris, and plants. They also must be deep enough to allow animals to retreat during unfavorable conditions such as during seasonal droughts, heat waves, or winter freezes (Gordon 1952, Rossell et al. 2019, Williams et al. 2020).

The rocks that are used for nesting in North Carolina often have specialized brood chambers that are higher above the ground and shorter in length than nearby crevices. These are typically narrow and provide stable microclimates that are cool and humid. They also facilitate the ability of females to defend their eggs from predators (Rossell et al. 2019). Individuals in a population in Virginia selected deeper crevices on rock outcrops as well as those in close proximity to standing trees. Trees could serve both to shade rock crevices and provide arboreal habitats for the salamanders (Smith et al. 2017, Waldron and Humphries 2005). Populations are generally found in mountainous regions as high as 1240 m (4400 feet) in elevation, but are often common at lower elevation sites in mesic to somewhat xeric habitats (e.g., Bruce 1968, Newman et al. 2018).

Green Salamanders have been collected beneath the loose bark of fallen trees and beneath artificial human structures (e.g., Barbour 1953, Pope 1928, Wilson 2003). They have been observed climbing and resting on woody shrubs and trees, and in some instances far from the nearest rocky nesting habitats. Recent studies show that non-nesting individuals sometimes leave rock formations during the summer and live in the adjoining forests where they are often weakly arboreal (Miloski 2010, Thigpen et al. 2010, Waldron and Humphries 2005, Wilson 2003). Most studies have found individuals using trees within 10-15 m of rock formations, but specimens have occasionally been found much farther out (Waldron and Humphries 2005, Wilson 2003). Individuals likely disperse between local outcrops during the summer months through forested landscapes (Williams et al. 2020, Wilson 2003). As such, hardwood forests that shade and surround rock formations, as well as forest corridors that allow movements between local rock formations, should be treated as essential habitats for this species. Mature, mesic hardwood forests appear to provide optimal terrestrial habitats for this species.
Biotic Relationships: The natural predators are poorly documented, but the juveniles and adults are probably taken by a variety of small predators such as the Ring-necked Snake, the Eastern Garter Snake, the Eastern Screech Owl and small mammals. Eggs that are abandoned by females are often consumed by predators. Barbour (1950) found Aneides eggs in the guts if two Diadophis punctatus from Big Black Mountain in eastern Kentucky, and Cameron et al. (2021) documented an unusual case in which an Eastern Ratsnake (Pantherophis alleghaniensis) consumed two gravid females that were in rock crevices in western North Carolina. Other suspected egg predators include invertebrates such as slugs and cave crickets.
See also Habitat Account for Montane Mesic Rock Faces and Crevices
Life History and Autecology
Breeding and Courtship: The adults breed during the warmer months of the year, with most courtship occurring in May and June. A secondary bout often occurs in September and October (Petranka 1998). Courtship in eastern Kentucky populations can occur anytime between late March and early November, but most individuals mate during the spring and fall months (Cupp 1971, 1991). Most adults in West Virginia populations mate in late May and early June, but a secondary breeding period occurs in September and October (Canterbury and Pauley 1994). Observations from other areas of the range suggest that mating is confined almost entirely to May and June (Petranka 1998). Mating in a Blue Ridge population in North Carolina appeared to be restricted to late May and early June based on the fact that males had swollen vents and produced spermatophores at this time (Gordon 1952). Annual breeding patterns are not fully documented, but the available data suggests that males breed annually and females biennially (Canterbury and Pauley 1994).

Males and females often pair together in rock crevices during the breeding season. Cupp (1971) observed courtship between a pair of green salamanders in a sandstone crevice. The following description is based on his observations as summarized by Petranka (1998). After encountering each other, the male and female first move in a tight circle with the chin of each resting on the tail of the other. As they circle, the male occasionally bites and nudges the female. At times, both individuals crawl over each other and mutually rub their snouts on each other while circling. During most of the courtship, the female straddles the male's tail. Periodically, the male stops and undulates the base of his tail laterally a few times. After again engaging in the tail-straddle walk, the male undulates the base of his tail, then arches the tail and deposits a spermatophore. The pair then moves forward and the female picks up the spermatophore while undulating the base of her tail. After the female picks up the spermatophore, the male exhibits jerking movements of the body and laterally undulates his tail. Cupp (1971) noted that courtship ceased after the female picked up a spermatophore. The pair parted soon thereafter.
Reproductive Mode: Females lay their eggs from late-May through July following the spring leaf-out and summer warm-up (Petranka 1998). The egg-laying period is similar for both southern and northern populations based on observations of nesting females in June or July in Alabama (Mount 1975), West Virginia (Canterbury and Pauley 1994, Green and Pauley 1987), Kentucky (Cupp 1991), and North Carolina (Cameron et al. 2021, Eaton and Eaton 1956, Gordon 1952, Gordon and Smith 1949). Nesting typically occurs in rock crevices or cavities, but there are a few rare instances of clutches being found beneath bark, inside rotting logs, or in other microhabitats away from rock formations. The egg-laying period in a local population lasts only 2-4 weeks. Most eggs at a North Carolina site were deposited in early to mid-June (Gordon 1952, Gordon and Smith 1949).

Each female lays her eggs in a small, tight cluster that is suspended by mucus strands from the roof of a cavity (Cupp 1991, Gordon 1952). When in vertical crevices, a female may attach her eggs to one side of the crevice rather than the roof. As many as 12 eggs may be laid in a 14-hour period and 1-2 days are required to lay an entire complement of eggs (Petranka 1998). The freshly laid ova are whitish yellow and the eggs average around 4.5 mm in diameter. Multiyear studies show that females often repeatedly nest in the same rock cavity (Cupp 1991, Gordon 1952).

Clutch sizes of local populations typically average between 15-20 eggs (Petranka 1998). Egg counts for 14 West Virginia nests varied from 12-27 and averaged 18 (Canterbury and Pauley 1994), while gravid females from the same population contained 12-30 mature ova eggs (mean = 22). The number of eggs in 21 Kentucky nests varied from 14-20 (Cupp 1991), while ovarian complements of five West Virginia females range from 20-32 ova (Lee and Norden 1973). The clutch sizes for 32 North Carolina nests varied from 10-26 and averaged 17-19 (Gordon 1952, Gordon and Smith 1949).

After ovipositing, females brood their eggs and remain with the hatchlings until they disperse from the nests. Brooding females regularly eat dead eggs in clutches, defend the eggs from predators, and probably reduce attacks from pathogens via their skin secretions (Gordon 1952, Petranka 1998). Cupp (1991) found that females brood their young for 3-5 weeks after they hatch. Females have little opportunity to feed when brooding. Outside of the breeding season they store fat for producing their next clutch, which may explain why most breed biennially. Development of the embryos to the hatching stages take 2-3 months depending on ambient temperatures (Petranka 1998). Eggs in a North Carolina population required 84-91 days to hatch (Gordon 1952), with the hatchlings first appearing in early September. Hatching in other populations has been documented from late August through mid-October (Petranka 1998).

Brooding females sometimes desert their eggs during droughts -- or for unknown reasons -- and deserted eggs invariably fail to survive to hatching (Gordon 1952, Snyder 1973). They succumb to both predation and fungal attacks. Snyder (1973) reported nest failure rates of 20-40%, with higher mortality during years with seasonal droughts. Embryonic survivorship to hatching was < 70% in Gordon's (1952) study of a western North Carolina population and survival in unguarded eggs was near zero. In another North Carolina study, Rossell et al. (2019) found that the percent of nesting females that hatched at least one offspring varied annually from 73–92% during a six-year period. Failed nests typically either lacked guarding females or had potential predators present.
Terrestrial Life History: The young juveniles disperse from the nesting cavities within a week to a few months after hatching and take up residence in cracks and crevices. Gordon (1952) noted that they often use moss-choked crevices and ledges and avoid the moss-free crevices that are used by the older juveniles and adults. During the warmer months of the year the juveniles and adults emerge from rock crevices or tree cavities on moist nights and forage on invertebrates. Canterbury and Pauley (1990) found that ants, beetles, and mites were the most numerically important prey in West Virginia specimens, but other prey such as orthopterans, spiders, dipterans, hemipterans, and lepidopterans were also taken. Lee and Norden (1973) found beetles, mosquitoes, ants, pseudoscorpions, mites, spiders, snails, and shed skin in other West Virginia specimens.

Several studies have examined short-term movement patterns using fluorescent powder or other methods. Individuals generally tend to move short distances of only a few meters during their nightly wanderings (Canterbury 1991, Cupp 2000, Gordon 1952, John et al. 2019, Miloski 2010), but occasionally move longer distances of 10-15 m or more, including into nearby trees. A given individual may often use several neighboring crevices as refuges and individuals tend to exhibit philopatry to their refuges. Male green salamanders are territorial and aggressively defend home territories in rock crevices from rival males (Canterbury and Pauley 1991, Cupp 1980, Petranka 1998). Resident males will often bite intruders or vigorously press their snouts along their backs, and are usually successful in defending their crevices.

The adults tend to reach their highest densities on rock faces from late October to mid-December after females leave their hatchlings (Cupp 1991, Gordon 1952, Williams et al. 2020). Individuals overwinter in deep crevices and are rarely encountered during the winter months, then re-emerge with the spring warm-up (Petranka 1998). Individuals monitored by Cupp (1991) in Kentucky began to reappear in rock crevices in early March and increased in number through late April. Gravid females emerged later than other individuals and eventually moved to crevices occupied by territorial males.

Lee and Norden (1973) documented three distinct size classes in West Virginia specimens which suggests that juveniles mature sexually 2-3 years after hatching. However, a detailed five-year study of marked individuals in West Virginia by Waldron and Pauley (2007) indicate that individuals require 7.5-8 years to reach sexual maturity. It is uncertain whether these findings reflect true population differences in age at first reproduction or biases due to methodologies. Waldron and Pauley (2007) found that growth rates slowly decline with age, but the adults continue to grow throughout their lives. Both sexes reach sexual maturity at about 45-46 mm SVL (Juterbock 1989, Petranka 1998, Waldron and Pauley 2007).

In addition to engaging in short nocturnal movements to forage, individuals sometimes make longer movements between rock outcrops during the warmer months -- particularly in late autumn prior to winter hibernation. Individuals at this time often move 50 m or more from their original point of capture (Canterbury 1991, Gordon 1952, Waldron 2000). Gordon (1952) noted that two marked specimens moved over 76 m (250 feet) over a 19 and 26 day period, while a juvenile moved about 107 m (350 feet) during a nine month period. Green salamanders have also occasionally been found crossing roads (Cupp 1991, Williams and Gordon 1961) or under cover objects far from the nearest rock outcrops, indicating that they are capable of long-distance movements (Williams et al. 2020). Using molecular markers, Johnson (2002) provided evidence which suggests that gene flow between local subpopulations up to 1 km apart was relatively high.
General Ecology
Population Ecology: Conservation biologists still have much to learn about forest habitat use and metapopulation organization in this species. Many regional populations show evidence of metapopulation organization with small rock outcrops patchily distributed across the landscape. The extent to which individuals disperse from one isolated rock outcrop to another is not fully known, but animals are capable of long distance movements and the surrounding forest does not seem to act as a barrier to dispersal. There are numerous records of green salamanders being found beneath the bark of fallen trees from the 1920's to the early 1950's when many old American Chestnut trees were dying and substantial amounts of old-growth forest covered eastern West Virginia, eastern Kentucky and eastern Tennessee (Barbour 1953, Fowler 1947, Gordon 1952, Pope 1928, Welter and Barbour 1940). The large, thick slabs of bark found on large old-growth logs and the numerous large, hollow trees presumably provided better microhabitats for foraging and nesting than the small logs and trees that are now present in secondary forests. Whether timbering and the loss of old-growth forests has compromised gene flow between rock-face populations has yet to be determined.
Community Ecology: The Green Salamander probably does not compete with salamanders that inhabit the forest floor, but Plethodon species that frequent rock outcrops could potentially compete with Aneides. Aneides and large Plethodon species sometimes stratify vertically on rock faces (Baltar 1983, Cliburn and Porter 1986, 1987). Aneides typically select cracks that are higher on either natural rock faces or in experimental chambers relative to those used by large Plethodon species. Canterbury and Pauley (1991) found that male A. aeneus, Plethodon glutinosus and P. kentucki were all mutually aggressive, and that A. aeneus could not successfully defend its space from the Plethodon species. This may explain patterns of microspatial segregation on cliff faces.
Adverse Environmental Impacts
Habitat Loss: The Green Salamander has a unique set of nesting requirements, including cool, moist, and shaded microenvironments in rock outcrops and cliff faces. Road cuts, timbering, and other disturbances that result in drier and hotter conditions can eliminate or degrade nesting sites. Mountaintop removal in Kentucky and West Virginia has undoubtedly eliminated many rock outcrop populations, and deforestation of areas between local rock outcrop populations can potentially eliminate critical dispersal corridors.
Interactions with Humans: Overcollecting by herpetologists -- along with illegal collecting for the pet trade -- is a concern given the very small sizes of many local rock-outcrop populations.
Status in North Carolina
NHP State Rank: S2S3
Global Rank: G3G4
Status in North Carolina: T
Environmental Threats: Because of its unique habitat requirements, the Green Salamander is vulnerable to several environmental threats. The shaded, humid microenvironments that are used by this species can be easily degraded by tree removal associated with timbering, road construction, strip mining, and the building and maintenance of powerline corridors. The destruction of old growth forests throughout the Appalachian region may have also compromised the ability of individuals to disperse between local rock outcrops and maintain metapopulation structure. Disease agents such as Bd (Batrachochytrium dendrobatidis) and Ranavirus that are associated with amphibian declines have been detected in many populations and poise a potential threat (SAFWA final report, 2019). And, long-term climate changes could potentially impact most populations.

There has been almost no effort to conduct long-term monitoring of populations until recently, so the status of populations from throughout the range is poorly documented. Resurveys of sites where populations were known to be present historically indicate that most populations both within and outside of North Carolina are still extant (SAFWA final report, 2019). In addition, intensive surveying, along with citizen science efforts, have documented numerous new populations. But, recent surveys have found only very small numbers of individuals locally (usually < 5-10), which suggest that many local populations are fragile and vulnerable to local extinction. The status of populations in North Carolina has been of particular concern ever since Synder (1991) and Corser (2001) reported a precipitous decline in the size of populations during the 1970's. Wilson's (2001) survey of sites showed little evidence of recovery through 2000. Long-term monitoring of populations within the state are needed to document future trends (Williams et al. 2020).
Stewardship: Wilson (2003) emphasized that -- while rock crevices currently represent the most critical habitat for A. aeneus -- future conservation efforts should recognize the importance of woody and arboreal habitats in surrounding forests. Forests should be allowed to return to old-growth stages that provide abundant breeding and foraging habits, as well as favorable dispersal corridors between existing rock outcrop colonies. Many rock outcrop colonies are very small (e.g., Rossell et al. 2019) and vulnerable to local extinctions. Restoring old growth conditions would likely enhance metapopulation persistence.

Photo Gallery for Aneides aeneus - Green Salamander

7 photos are shown.

Recorded by: B. Bockhahn, J. Thomson
Macon Co.		Recorded by: B. Bockhahn, J. Thomson
Macon Co.
Recorded by: M.Briley
Transylvania Co.		Recorded by: K. Bischof, E. Corey
Transylvania Co.
Recorded by: K. Bischof, E. Corey
Transylvania Co.		Recorded by: K. Bischof, E. Corey
Transylvania Co.
Recorded by: Todd Pierson
Macon Co.