Amphibians of North Carolina
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NC Records

Desmognathus wrighti - Pygmy Salamander


Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae Other Common Name(s): Southern Pygmy Salamander
Taxonomic Comments: Prior to 2010, populations of a a tiny Desmognathus species that has a reddish brown to coppery bronze dorsal stripe with a dark herringbone pattern down its center constituted a single species, D. wrighti. Crespi et al. (2010) split D. wrighti (sensu lato) into two species (D. wrighti; D. organi) based on genetic differences, as well as differences in the morphology, ecology, and life histories of the two forms. Both species are southern Appalachian endemics, with the French Broad River Basin dividing the ranges of the two. Desmognathus organi occurs north of the French Broad River to as far north as Whitetop Mountain and Mount Rogers in southwestern Virginia and is generally restricted to mid- and higher-elevation forests (Crespi et al. 2003, 2010) . Desmognathus wrighti occurs south and west of the French Broad River in southwestern North Carolina and extreme eastern Tennessee (Crespi et al. 2010, Niemiller and Reynolds 2011, Rossell et al. 2018). It also occurs in mid- to higher-elevation forests, but shows a general tendency to use lower-elevational sites more frequently than D. organi (Crespi et al. 2003, Crespi et al. 2010). These species are very similar in general size, morphology, and patterning and are most easily separated using the range and collection locality.
Species Comments:
Identification
Description: This is a tiny Desmognathus with 14 costal grooves, a light brown dorsum, an inverted V-shaped mark behind the eyes, and a conspicuous herringbone pattern that runs down the center of the back. Individuals are occasionally collected with the dorsum either yellowish or brick red, and in some individuals the herringbone pattern may be missing or reduced to a line of dots down the mid-line (Crespi et al. 2010). The tail is rounded in cross-section and is less than or equal to the length of the body. The top of the head and snout is rugose, and the eyelids are often coppery colored (Petranka 1998). Many specimens have a wavy dark brown dorsolateral line on either side of the body that adjoins the dorsal ground color. The venter is flesh-colored and lacks dark mottling. Golden iridophores are well-developed on the ventral musculature and percardium of the heart and are visible through the ventral body wall. They form an elliptical pattern that extends from the area between the forearms to just before the cloacal vent.

The total length of adults ranges from 35-55 mm, but only rarely exceeds 50 mm (Crespi et al. 2010). The males have a U-shaped mental gland on their chin that is used during courtship. This species can potentially be confused with young juveniles of the Desmognathus ochrophaeus complex. The coppery-colored eyelids, the herringbone pattern on the back, and the short tail that is generally no longer than the body length are good field traits for separating this species from the young juveniles of other Desmognathus species such as D. ocoee. Individuals also typically have a prominent dark line on each side of the head that runs from the eye to the snout. The line is either absent or poorly developed in members of the Desmognathus ochrophaeus complex.

The hatchlings have 4-5 pairs of light dorsal spots and very short tails. The gills are lost at or shortly before hatching and there is no aquatic larval stage (Petranka 1998). Desmognathus organi is very similar to D. wrighti, but is slightly larger and stockier on average. It also has far fewer iridophores on the ventral musculature. We recommend using the collection locality (north or south of the French Broad Valley) in assigning names to specimens.
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Observation Methods: Individuals are most easily collected either by turning cover objects or searching the forest floor and low-lying vegetation on wet or rainy nights.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: The Pygmy Salamander is a southern Appalachian endemic that is found south and west of the French Broad River Basin in North Carolina and extreme eastern Tennessee. This species is widespread in the Great Smoky Mountains and occurs as isolates in other large mountain ranges in North Carolina, such as the Nantahalas.
Distribution Reference: Crespi et al. (2010)
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: Pygmy Salamanders occur primarily at mid to higher elevations in the Blue Ridge Mountains. They can be relatively common in spruce-fir forests on the highest peaks south of the Asheville Basin (Tilley and Hugheey, 2001), but also occur in stands of Northern Hardwoods and Cove Forests at elevations as low as 2,400'. This is a highly terrestrial species with no aquatic larval stage. The adults forage widely across the forest floor and can be found during the summer months substantial distances from aquatic sites (Petranka 1998).
See also Habitat Account for General High Elevation Forests
Life History and Autecology
Breeding and Courtship: Courtship has not been described but presumably is very similar to that of D. organi and involves a biting phase that is followed by the tail-straddle walk.
Reproductive Mode: Females are thought to lay their eggs during mid to late summer based on dissections of females (Hining and Bruce 2005). Nesting females have yet to be found, but they presumably lay small clusters of eggs and remain coiled about them through hatching as seen for D. organi.
Aquatic Life History: Pygmy Salamander embryos resorb their gills shortly before hatching and there is no larval stage.
Terrestrial Life History: The juveniles and adults live on the forest floor during the summer months where they forage for small invertebrates. They are most commonly found during the day beneath woody debris. Small cover objects such as decomposing limbs and logs offer ideal microhabitats, but individuals also can be found in leaf litter and beneath slabs of bark, stones, and other cover objects (Rossell et al. 2018). Individuals forage at night outside of cover and often perch on low vegetation during wet weather where they take small invertebrates. Specimens that were collected by Smith and Petranka (2005) during the summer months avoided the streambed proper and were most abundant within a 4-16 m zone from the streambed. Many others were found beyond this zone on the forest floor. Rossell et al. (2018) noted that 78% of pygmy salamanders that they collected in western North Carolina (pooled data for both D. organi and D. wrighti) were >30 m from seeps or streams.

Much like D. organi, many individuals appear to move into moist microhabitats in or near headwater streams and associated seepages to overwinter and nest (Crespi et al. 2010, Petranka 1998). Bruce (1977) found D. wrighti in saturated mud and gravel in the banks of seepages in the Cowee Mountains of North Carolina in autumn, mid-winter, and early spring, while Hining and Bruce (2005) found them to be common within 10 m of seepages and streams during March and April where they lived in small depressions beneath moist leaf litter, moss clumps, logs, and other cover.


General Ecology
Population Ecology: Males studied by Hining and Bruce (2005) became sexually mature when 2-3 years old, while females appeared to first oviposit when three years old. Rossell et al. (2018) found that sex ratios in North Carolina populations did not deviate significantly from 1:1, and that adults outnumbered juveniles by about 2:1.
Community Ecology: Desmognathus species in the southern Appalachians exhibit niche partitioning with respect to the distance that different species live from streams and seepages (Hairston 1949, 1986). The Pygmy Salamander is one of the most terrestrial of all Desmognathus species. During the summer months non-nesting individuals generally avoid areas immediately next to streams and seepages where larger predatory species such as D. quadramaculatus and D. monticola reside (Smith and Petranka 2005). They also tend to use smaller cover objects on the forest floor than other salamanders, which may help to reduce competitive or predatory interactions with these species (Rossell et al. 2018).
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S3
Global Rank: G3
Status in North Carolina: SR

Photo Gallery for Desmognathus wrighti - Pygmy Salamander

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Recorded by: Todd Pierson
Macon Co.