Amphibians of North Carolina
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NC Records

Plethodon richmondi - Southern Ravine Salamander


Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic Comments: Populations of a medium-sized, short legged and slender Plethodon that occurs in the eastern US were traditionally treated as a single species, P. richmondi (sensu lato). Highton (1972, 1999a) analyzed protein variation in this group and split them into four species. An initial split involved recognizing P. hoffmani and P. richmondi as separate species (Highton 1972). This was followed by splitting each of these into two parapatric, cryptic species pairs: P. hoffmani - P. virginia and P. richmondi - P. electromorphus (Highton 1999a). As currently recognized, P. electromorphus is a northern form which ranges from southwestern Pennsylvania, Ohio, and southeastern Indiana south to extreme northern Kentucky and northwestern West Virginia. In West Virginia it occurs east of the New and Kanawha rivers. Plethodon richmondi (sensu stricto) occurs farther south in northern and eastern Kentucky, southern West Virginia, northeastern Tennessee, southwestern Virginia and northwestern North Carolina. These two species cannot be distinguished based on morphology and patterning and are best identified by range. Although they form an extensive hybrid zone in northern Kentucky (Highton 1999b), they are generally viewed as being separate evolutionary species.
Species Comments:
Identification
Description: Plethodon richmondi is a medium-sized, elongated Plethodon with short legs relative to body size and a modal number of 20-23 costal grooves between the limbs. The body is noticeably slender and worm-like, and the tail of adults comprises about 50% of the total length. The ground color of the dorsum and sides varies from dark brown to black. The dorsum is flecked with varying amounts of brassy or golden specks, along with scattered silvery-white flecks (Petranka 1998). The brassy or golden flecking can be so concentrated on some individuals that it produces a faint dorsal stripe that extends well onto the tail. The lower sides of some individuals are often heavily frosted with silvery white speckling. The belly is uniformly dark except for scattered silvery-white flecks, while the throat is lighter colored than the belly and often weakly mottled. The undersurface of the tail is uniformly slate gray to black. Males have a crescent-shaped mental gland near the apex of the lower jaw, along with papillae on the inside of the vent (Petranka 1998). Mature females in populations in northern Kentucky and northeastern Tennessee average 5% larger in SVL than mature males (Nagle 1979, Wallace 1969). Adults vary from around 6.5-14.5 cm TL.

The hatchlings are light gray above, have an immaculate belly, and average 14-15 mm SVL. They sometimes have reddish pigmentation on the cheeks, front legs, and sides that disappears with age. The older juveniles resemble the adults in coloration, but have proportionately shorter tails and longer legs (Petranka 1998). This species superficially resembles the unstriped phase of P. cinereus, but P. cinereus lacks the golden or brassy speckling on the dorsum and has heavy mottling on the belly. It also resembles the unstriped form of P. ventralis, but the latter usually has orangish-red pigment near the base of the forearm and on the belly. It also is allopatric and occurs farther south in the French Broad River Valley in western North Carolina.
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AmphibiaWeb Account
Distribution in North Carolina
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: The Southern Ravine Salamander lives in ravines and on moist, wooded hillsides and slopes. Mature forests with a well-developed leaf litter layer, moist, friable soils, flat rocks, and large logs provide ideal conditions (Baecher and Richter 2018, Petranka 1998). This species tends to frequent sites with rocky habitats and is often locally abundant in or about talus slopes, at the bases of rock outcroppings, or at sites where large flat rocks abound. It is generally uncommon or absent from floodplains or very dry ridge tops with thin soils.
Biotic Relationships: Plethodon richmondi coexists with a variety of predators and potential competitors, but little information is available on their interactions. The Ring-necked Snake (Diadophis punctatus) feeds regularly on small salamanders and Cupp (1994) found that P. richmondi will avoid substrates that are marked with snake odors. When uncovered beneath surface objects, P. richmondi often assumes a coiled, motionless position which would likely make them less conspicuous to predators such as black bears that are turning rocks and logs in search of prey (Dodd 1990).
See also Habitat Account for General Montane Mesic Forests
Life History and Autecology
Breeding and Courtship: The adults court and mate from autumn through early spring, but patterns vary geographically. Nagel (1979) found that mating in an eastern Tennessee population occurs from November through March based on collections of males with sperm-filled vas deferentia and females with spermatophores in their cloacae. In West Virginia the adults mate in April and May and do not have a fall breeding season (Jewell and Pauley 1995). Little data are available on courtship behavior, although the adults are known to engage in a tail-straddle walk like other plethodontids (Petranka 1998).
Reproductive Mode: The females are sometimes active on the ground surface during the winter months, but surface activity increases during the spring warm-up. They feed during this period and store fat reserves in their tails before moving into deep underground passageways to lay their eggs. Petranka (1979) was unable to find any radioactively tagged individuals in talus during the summer months, which suggests that individuals moved at least 0.5 m below ground to nest and aestivate. Females with large ovarian eggs can be found in March and April, and most appear to oviposit below ground from late April through May (Petranka 1998, Wallace 1969). Females in West Virginia oviposit biennially (Jewell and Pauley 1995), while males presumably mate annually as is the case for other Plethodon species. Females in a Tennessee population appear to oviposit in late May through June (Nagel 1979), which corresponds to the time when they move into underground summer retreats. The females presumably brood their eggs like other small eastern Plethodon. Most hatchlings and young juveniles remain underground and do not emerge on the surface until the following spring.

Estimates of clutch size are based almost entirely on counts of ovarian complements. The average number of mature ova in 94 Kentucky females that were examined by Wallace (1969) was 8.5, while the number of mature ova in 50 Tennessee females examined by Nagel (1979) varied from 5-11, averaged 8.3, and was independent of female SVL. The embryos presumably hatch in late summer before the adults resurface. Wallace and Barbour (1957) found two adults, two hatchlings and two eggs at the hatching stages on 23 August in northern Kentucky under a flat limestone rock that was 25 cm beneath the ground.
Terrestrial Life History: In North Carolina individuals begin emerging from their underground summer retreats in mid to late September and are active on the ground surface until cold winter weather sets in around mid-November. The adults are generally inactive during the coldest winter months, although Nagel (1979) found large numbers of individuals during January and February in Tennessee at a relatively low elevation site. Surface activity increases again beginning in late February or March and individuals remain active on the ground surface until late April or early May. Individuals are occasionally collected during the summer months, but the great majority move underground and resurface beginning in September. Nagel (1979) noted that juveniles are more commonly encountered on the ground surface during the late-winter and spring months compared to the fall months.

Surface-active animals hide in leaf litter and beneath surface cover during the day and emerge with the onset of darkness on warm, moist nights to feed and mate. They presumably feed on small invertebrates, but dietary studies are lacking. The tail is used as a fat-storage organ and provides stored energy for animals during the summer months. Animals that emerge in late-summer have relatively thin tails compared with those collected in the spring (Green and Pauley 1987). This suggests that individuals feed very little while underground.

Nagel (1979) found that males in a Tennessee population mature sexually during the fall of their third year of life when 38-42 mm SVL. Most females require an additional year to mature, and probably do not oviposit for the first time until the following spring or summer. The smallest female with maturing eggs in Kentucky specimens that were examined by Wallace (1969) was 35 mm SVL.
General Ecology
Population Ecology: Mechanisms that regulate local population sizes are unknown. Thurow (1976) noted that P. richmondi is generally much less aggressive that other eastern Plethodon species, which implies that it may be only weakly territorial.
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S3
Global Rank: G5
Status in North Carolina: W2

Photo Gallery for Plethodon richmondi - Southern Ravine Salamander

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Recorded by: Steve Hall and Bo Sullivan
Ashe Co.