Amphibians of North Carolina
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NC Records

Desmognathus santeetlah - Santeetlah Dusky Salamander


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Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic Comments: Desmognathus fuscus-like populations in the Unicoi, Great Smoky, and Great Balsam ranges in western North Carolina were recognized as a new species, D. santeetlah, by Tilley (1981). This species consists of a series of high-elevation populations that differ in several characteristics from nearby low-elevation populations of what Tilley (1981) at the time considered to be D. fuscus. Tilley (1981) noted that D. santeetlah reaches sexual maturity at a slightly smaller size, is generally darker above with inconspicuous markings, has slightly different body proportions, and has fewer dorsal spots on the larvae. In addition, electrophoretic analyses show that the two forms are fixed for alternate electromorphs at three protein loci. Later studies revealed that what was thought to be D. fuscus at lower elevational sites that surround the range of D. santeetlah is not, and may represent a mixture of both D. conanti to the south and two members of an unresolved and perplexing complex of Desmognathus forms in eastern Tennessee to the north (see Tilley et al. 2013).

Later studies showed that D. santeetlah extensively interbreeds where it comes into geographic contact with the low-elevation forms in a broad geographic area along the northwest escarpment of the Great Smoky Mountains (Tilley 1981, 1988). Despite genetic and life history differences that occur between these groups, there is little evidence that D. santeetlah is reproductively isolated from the lower elevation forms based on genetic data and courtship trials (Tilley 1988, Maksymovitch and Verrell 1993, Verrell 1990). Populations of D. conanti and D. santeetlah in the Unicoi Mountains are separated by a slight elevational gap and do not have opportunities to interbreed there.

In their most recent studies of D. conanti based on mtDNA, Beamer and Lamb (2020) recognize five major clades of D. conanti and found that D. santeetlah comprised a well-supported clade of its own. However, D. santeetlah was nested within a larger group that contained the five D. conanti clades. In addition, specimens that phenotypically resemble low-elevation D. conanti (but see Tilley et al. 2013) had haplotypes of D. santeetlah, a feature that likely reflects the widespread hybridization of these forms within the Great Smoky Mountains, and possible hybridization with D. conanti at some distant point in their evolutionary history.

Desmognathus santeetlah is one of many taxonomically challenging groups of Desmognathus in eastern US (Beamer and Lamb 2020). Despite evidence of extensive hybridization with other forms, it is treated by authorities as a valid species, and we continue do so here.

Species Comments:
Identification
Description: This is a medium-sized species of Desmognathus with a tail that is weakly keeled or trigonal distally. The toe tips lack cornifications and subsequently do not appear black-tipped. Most specimens are dull colored with yellowish-brown to greenish or greenish-brown coloration above. A straight or slightly undulating dorsolateral dark stripe is usually present, but is often thin, diffuse, and broken (Tilley 2000a). These stripes often enclose reddish pigment on the dorsum, particularly in younger specimens. Yellow pigmentation is most evident along the ventrolateral surfaces and under the base of the tail. Many specimens have numerous patches of iridophores scattered over their dorsal, lateral, and ventral surfaces, and the venter of many specimens has a "salt and pepper" pattern with a yellowish wash. Old individuals are usually greenish-brown dorsally and laterally, often with abundant iridophore patches but no other discernible dorsal pattern (Tilley 2000a). The hatchlings average around 8-9 mm SVL and the larvae have about 10 spots between the limbs that are often represented in the adults as depigmented areas or areas containing concentrations of reddish pigment. This species often coexists with several other Desmognathus species and is best identified in the field by a combination of size, the absence of cornified toe tips, the triagonal tail, and the yellowish wash that is often conspicuous on the underside of the tail. Hybrids are highly variable in coloration and patterning, and may consist of both dull and brightly colored and patterned individuals (Tilley 1988).
Online Photos:    Google   iNaturalist
Observation Methods: Specimens are most easily collected by turning rocks or other cover objects in or near streambeds or seeps.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: Desmognathus santeetlah is restricted to the Unicoi, Cheoah, Great Smoky, and Great Balsam mountain ranges of the Blue Ridge in southwestern North Carolina and adjoining areas of eastern Tennessee (Tilley 1981, 2000a). The species ranges along the crest of the Great Balsam Mountains and Pisgah Ledge to at least as far as Pigeon Gap in Haywood-Transylvania counties (see range map above). The southern extent of its range in the Unicoi Mountains has not been established. This is mostly a high-elevation species, and pure forms has rarely been found below 3000 feet in elevation. Hybrids in the Great Smoky Mountains with D. conanti genes extend well into the lower valleys (Tilley 1988).
Distribution Reference: Tilley (1981, 2000a)
County Map: Clicking on a county returns the records for the species in that county.
GBIF Global Distribution
Key Habitat Requirements
Habitat: The Santeetlah Dusky Salamander is a semiaquatic species that is typically found in closed-canopy habitats in the immediate vicinity of cool seeps and headwater streams (Beane et al. 2010, Tilley 1981). Most specimens found by Petranka and Smith (2005) were either in the streambed proper or within 4 m of the streambed.
See also Habitat Account for Montane Perennial Creeks and Small Streams
Life History and Autecology
Breeding and Courtship: Jones (1986) found males with the vasa packed with sperm during every month of his study (March-December), suggesting that courtship likely occurs throughout the warmer months of the years when adults are active. When courting, the adults engage in a set of rather stereotypic behaviors that appear to be essentially identical for D. conanti, D. santeetlah, and D. fuscus. Maksymovitch and Verrell (1992, 1993) provide details for D. santeetlah. The following general account of courtship behavior is from Petranka (1998).

When a male encounters a receptive female, he engages in a 'butterfly walk' in which he approaches while synchronously rotating the forelimbs in a manner that is similar to the butterfly stroke of swimmers. The male may repeatedly jerk his body to-and-fro and undulate his tail during this period. The male eventually places his snout on the female's back, arches his body upward, and raises his belly and forelimbs clear off the ground. The hindlimbs and tail are kept pressed to the substrate, and the snout is pressed downward with considerable force against the female's back. This not only brings the hedonic glands into contact with the female, but also causes tactual stimulation from the enlarged premaxillary teeth of the males. The male then violently snaps his body straight, which often propels him 5-10 cm or more from the female. He then returns and repeats the entire sequence several times. Snapping lacerates the females skin and vaccinates the female with secretions from the male's mental gland. The male may also position himself such that his undulating tail is beneath the chin of the female. From this position, he will also snap the female's dorsum or neck to vaccinate the female. In addition to snapping, a male may slowly pull his teeth across the female's dorsum to vaccinate her. This phase of courtship often lasts for 1-2 hours.

Once the female is fully receptive the male moves forward and undulates his tail as it passes under her chin. The female saddles the male's tail and the courting pair moves forward in a tail-straddle walk. The male eventually begins a series of lateral pelvic rocking movements then deposits a spermatophore. Immediately thereafter, he arches the base of the tail upward and bends the tail sharply to one side. He then violently undulates the tail. The female holds her chin against the base of the bent tail and the courting pair moves forward quickly. As the female passes over the spermatophore, she picks up the sperm cap with her cloacal lips. The animals decouple shortly thereafter.

Maksymovitch and Verrell (1993) compared the sexual compatibility of individuals from three widely separated populations of D. santeetlah and found statistically significant differences in levels of sexual compatibility among populations. These data are consistent with other studies of salamanders which indicate that aspects of mate recognition systems can diverge among conspecific populations in the absence of geographic isolation (Petranka 1998).
Reproductive Mode: Females lay globular clusters of eggs during the summer months and brood them through hatching. They have most commonly been found beneath moss mats that cover rocks or logs in or along the edges of seepages or headwater streams. Jones (1986) found that most females oviposit from around mid-May through early July in the Unicoi Mountains. The clutch size of populations in the Smokies averages around 17-20 eggs (Beachy 1993b, Tilley 1988), while Jones (1986) reported a mean of 23 ova in Unicoi populations.
Aquatic Life History: Dietary studies have not been conducted for the larvae, but they presumably feed on tiny invertebrates such as midge larvae that are found in seepages and streams. The larval period of populations in the Unicoi Mountains appears to be slightly less than 1 year, with the smallest metamorphs ranging from 9-12 mm SVL (Jones 1986).
Terrestrial Life History: The juveniles and adults live in close proximity to running water. The diet is undocumented, but they presumably are opportunistic, generalist predators on invertebrates like other dusky salamanders. Jones (1986) found that males begin to reach sexual maturity when around 30 mm SVL, versus 33–35 mm SVL for females. The males reach sexual maturity when around 2-years old, while females require an additional year of growth.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S3S4
Global Rank: G3G4Q
Status in North Carolina: W2
Environmental Threats: Most populations of the Santeetlah Dusky Salamander are in either the Great Smoky Mountains National Park, the Blue Ridge Parkway, or national forests and are protected from environmental disturbances from mining and intensive timber harvesting. Feral hogs often disturb seepages and could potentially impact populations by consuming salamanders or destroying nesting microhabitats.

Photo Gallery for Desmognathus santeetlah - Santeetlah Dusky Salamander

4 photos are shown.

Recorded by: Todd Pierson
Swain Co.		Recorded by: Owen McConnell
Graham Co.
Recorded by: Jim Petranka
Swain Co.
Comment: Distribution of D. santeetlah relative to other Desmognathus species in western North Carolina based on genetically identified specimens (courtesy of Alex Pyron). 		Recorded by: Jim Petranka
None Co.
Comment: Distribution of D. santeetlah relative to other Desmognathus species in western North Carolina based on genetically identified specimens (courtesy of Alex Pyron).