Amphibians of North Carolina

Scientific Name:	Common Name:		Family (Alpha):

Plethodontidae Members:
Desmognathus organi - Northern Pygmy Salamander

Taxonomy

Class: Amphibia

Order: Caudata

Family: Plethodontidae

Subfamily: Plethodontinae


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, Crespi et al. 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 bronze to yellowish-brownish dorsum, an inverted V-shaped mark behind the eyes, and a conspicuous herringbone pattern that runs down the center of the back. The tail is rounded in cross-section and is less than half 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. Depending on the locale, golden iridophores may be either absent from the ventral musculature or scattered to produce goldish speckling. The adults vary from around 40-60 mm TL (most are > 50 mm), and females tend to be heavier and have proportionately longer tails than the males (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 less than the body length are good field traits for separating this species from the young juveniles of other Desmognathus species. Individuals also typically have a prominent dark line on each side of the head that runs from the eye to the snout that 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 mean SVL and TL of hatchlings examine by Organ (1961a) varied from 7.0-8.1 and 10.0-11.2 mm, respectively. 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 River Valley) in assigning names to specimens.

Online Photos: Google iNaturalist

Observation Methods: Individuals can be collected by turning woody debris on the forest floor. They are active on the ground surface during periods of wet or rainy weather and can often be observed climbing on low vegetation at night.

AmphibiaWeb Account

Distribution in North Carolina

Distribution Comments: This species ranges from Whitetop Mountain and Mount Rogers in southwestern Virginia southwestward through western North Carolina and northeastern Tennessee to just north of the French Broad River Basin. In North Carolina, populations have been found as far south as northern Madison Co. and eastern Buncombe Co at mid- to higher elevations. As of 2022, all of our records are from the Blue Ridge Mountains at mid- to high elevations.
Distribution Reference: Crespi et al. (2010)
County Map: Clicking on a county returns the records for the species in that county.


GBIF Global Distribution

Key Habitat Requirements

Habitat: Desmognathus organi is most commonly found in forests above 3600' (1100 m) in the southern Appalachians (Crespi et al. 2010), including the Black Mountains, Grandfather Mountain, and Roan Mountain in North Carolina. Local populations occur in cove forests, northern hardwood forests, and spruce-fir forests, but populations appear to reach their highest densities in spruce-fir forests (Rossell et al. 2018). Mature forests with large amounts of woody debris on the forest floor are ideal habitats. Rich cove forests with mature or old-growth hardwoods can also support large populations of this species. Crespi et al. (2010) found that the habitats occupied by D. organi generally receive less annual rainfall and are cooler on average than those used by D. wrighti. Despite these climatic differences associated with the range and elevational differences, Rossell et al. (2018) found almost no differences in the microhabitats that are used by these species in North Carolina.

See also Habitat Account for General High Elevation Forests

Life History and Autecology

Breeding and Courtship: Most of our knowledge of the life history of Northern Pygmy Salamander is based on Organ's (1961a, b) detailed studies in southwestern Virginia. Mating occurs primarily during the fall and spring months, and adults that Organ maintained indoors courted from September-October and April-May.

During courtship, a male that encounters a female may initially clamp his jaws to her tail, body, or head, and in some cases restrain the female for several hours (Houck 1980). This biting behavior presumably functions to abrade or cut the skin and introduce mental gland secretions into the female's circulatory system. Adults eventually engage in a tail-straddle walk that is essentially the same as that of D. orestes and D. fuscus. It culminates in a male depositing a spermatophore and the female picking up the sperm cap (Petranka 1998). The spermatophore is about 2.5 mm high. The base and stalk are clear and support a milky white sperm cap (Organ 1961b). Males often chase and bite rival males that attempt to court females.

Reproductive Mode: Females lay clusters of eggs and remain coiled about their eggs through hatching. Organ (1961a, b) found six clusters in late developmental stages on 16 October in Virginia beneath the bank of a headwater stream. The eggs were 3.5 mm in diameter and were suspended by a single pedicel formed from the outer capsules of one or two eggs. The number of eggs per clutch varied from 3-8 and averaged 6. The number of mature ova in females examined by Tilley (1968) varied from 6-14, averaged around 10, and was positively correlated with SVL. Although females often nest in or near seepages or headwater streams, those at high elevation sites that are far removed from running water presumably oviposit in moist underground retreats. Organ (1961a) considered D. wrighti to be a biennial breeder, but Tilley (1968) argued that most females breed annually.

Aquatic Life History: The developing embryos have rudimentary gills, but these are lost shortly before or after hatching and there is no aquatic larval stage.

Terrestrial Life History: The juveniles and adults are fully terrestrial and live in or on forest floor habitats 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 actively forage at night outside of cover and often perch on low vegetation during wet weather where they take small invertebrates. Petranka and Murray (2001) studied a population in western North Carolina and noted that the adults were very sensitive to moisture levels. They often perched on vegetation on nights when the foliage was dripping wet, but quickly curtailed surface activity as conditions dried. They were unsuccessful in estimating densities based on removal sampling, but provided a minimum estimate of at least 0.37 salamanders/m2 in streamside habitats. Perching on vegetation may be a way to avoid larger, predatory salamanders that forage from the leaf litter below (Petranka 1998).

Although this species is often collected far from running water (e.g., Rossell et al. 2018), local populations are often found near headwater streams and associated seepages that serve as overwintering and nesting sites (Petranka 1998, Crespi et al. 2010). Organ (1961a, b) found large numbers of D. organi in streambanks from October through mid-May, but relatively few in mid-June. Most males appeared to disperse to forest floor habitats after the arrival of warm weather in late-spring. It was uncertain if the mature females remained near winter hibernacula all year long, or moved from forest floor microhabitats in early summer to nests in streambanks and seepages.

General Ecology

Population Ecology: In southwestern Virginia, the males become sexually mature when about 3.5-years old and > 24 mm SVL. The females become sexually mature when 4.5-years old and first oviposit when 5-years old (Organ 1961a, Petranka 1998). Age-specific mortality tends to increase with age and annual survivorship is higher than in other Desmognathus species. The adults may live as long as 10 years. 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 Northern Pygmy Salamander is one of the most terrestrial of all Desmognathus species. During the summer months non-nesting individuals generally avoid areas next to streams and seepages where larger predatory species such as D. kanawha, D. mavrokoilius and D. monticola reside. They also tend to use smaller cover objects on the forest floor than other salamanders that 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: S2S3

Global Rank: G3

Status in North Carolina: SR

Environmental Threats: Hicks and Pearson (2003) examined how past land uses have impacted this species in North Carolina. At reforested sites that were previously logged or farmed, populations were still markedly depressed relative to undisturbed sites after about 50 years of forest recovery from past disturbances.

Photo Gallery for Desmognathus organi - Northern Pygmy Salamander		8 photos are shown.
	Recorded by: A. Burgos-Melendez, E. Jonas, R. Passino Watauga Co.	Recorded by: ASH Yancey Co.
	Recorded by: K. Bischof Yancey Co.	Recorded by: K. Bischof Yancey Co.
	Recorded by: K. Bischof, E. Corey, T. DeSantis Yancey Co.	Recorded by: s. mcbean Avery Co.
	Recorded by: S.Lambiase Watauga Co.	Recorded by: S.Lambiase Watauga Co.

Desmognathus organi - Northern Pygmy Salamander

Photo Gallery for Desmognathus organi - Northern Pygmy Salamander

8 photos are shown.