Amphibians of North Carolina
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Stereochilus marginatus - Many-lined Salamander



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Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Spelerpinae
Taxonomic Comments: The Many-lined Salamander occurs from Virginia to Florida, but we are unaware of any detailed molecular studies that have examined patterns of geographic variation in this species.
Species Comments:
Identification
Description: The Many-lined Salamander is a small, slender, short-tailed salamander that is brownish to dull yellow above with an indistinct, dark, dorsolateral band that runs through the eye onto the tail. The back is usually unmarked, but specimens occasionally have a few small, indistinct dark or light spots. A series of fine, parallel, dark lines or streaks usually occurs along the sides of the body. In many cases these are indistinct or reduced to a series of spots. The venter is dull yellow with scattered brown or black flecks (Beane et al. 2010, Petranka 1998). The tail is laterally compressed towards the tip and has a prominent dorsal keel. Adults vary from 6.5-11.5 mm TL and there is no sexual dimorphism in body size (Bruce 1971).

The hatchlings are strongly bicolored, with dark brown above and yellow below. Small white to yellowish spots occur on the top and sides of the head and body. Unlike many pond-dwelling larvae, the hatchlings have functional limbs at hatching. The dorsal fin initially extends anteriorly nearly to the head but becomes reduced during the early larval period and is confined to the tail in larvae > 15 mm SVL (Bruce 1971, Schwartz and Etheridge 1954). The smallest hatchlings collected by Bruce (1971) were 8 mm SVL. Older larvae generally resemble the adults in color and general form, but often have mottling on the dorsum (Petranka 1998).
Technical Reference: Ryan (AmphibiaWeb, 2021)
Online Photos:    Google
Observation Methods: The larvae and adults are most easily obtained by dipnetting through leaf litter and other bottom debris, or by dipnetting around Sphagnum moss mats and the bases of aquatic plants.
AmphibiaWeb Account
Distribution in North Carolina
Distribution Comments: This species is found on the Atlantic Coastal Plain from southeastern Virginia to northeastern Florida.
Distribution Reference: Beane et al. (2010); Petranka (1998)
County Map: Clicking on a county returns the records for the species in that county.
Key Habitat Requirements
Habitat: This is an aquatic or semi-aquatic species that inhabits a variety of permanent or nearly permanent aquatic habitats. These include gum and cypress swamps, woodland ponds, borrow pits, drainage ditches, canals, and sluggish streams (Beane et al. 2010, Petranka 1998). Individuals are often found in aquatic microhabitats that provide both cover and foraging sites for invertebrates. Both the larvae and adults can be found in sphagnum mats, leaf litter, bottom debris, and dense aquatic vegetation. Although the Many-lined Salamander is primarily aquatic, it also has been found on land beneath logs, in wet Sphagnum moss mats, and in other semiaquatic microhabitats along the margins of ponds and sluggish streams. This is particularly true during droughts or periods of dry weather when the aquatic habitats contract in size. Foard and Auth (1990) reported digging up adults from exposed riverbeds during drought conditions, and Bruce (2008) found the adults buried in muck in the exposed beds of shallow pools that had dried.
Biotic Relationships: Stereochilus coexists with a variety of aquatic predators such as predatory fishes, small snakes, wading birds, and larger salamanders. However, almost no information is available concerning predator-prey interactions with these species.
See also Habitat Account for Coastal Plain Still and Sluggish Waters
Life History and Autecology
Breeding and Courtship: The adults breed in the autumn and individuals of both sexes reproduce annually (Petranka 1998). In a North Carolina population studied by Bruce (1971), breeding peaked in November. Most males at this time had swollen vents and vasa deferentia packed with sperm. A similar pattern was evident for males in a second North Carolina population (Bruce 2008). The ratio of males to females was about 1:1 in this population, compared to 2.5:1 in a Georgia population that was studied by Foard and Auth (1990).

Detailed descriptions of courtship behavior have not been published, but the adults are known to engage in a tail-straddle walk after a preliminary period of nosing and rubbing of the female's snout by the male. Females often turn their tails forward while performing the tail-straddle walk (Noble and Brady 1930).
Reproductive Mode: Females begin laying eggs several weeks after mating and select microhabitats in or near aquatic sites. The eggs are attached singly by short pedicels to rootlets, pine needles, plant stems, moss fibers, and the undersides of logs (Petranka 1998). When ovipositing on land, females tend to clump their eggs relatively tightly and in about 30% of cases brood the eggs (Rabb 1956, Schwartz and Etheridge 1954). When ovipositing in water, they scatter the eggs more widely and almost never brood.

Wood and Rageot (1963) found 43 clutches in southeastern Virginia that were laid both in water and on land. Most were found 8-15 cm below the water surface in quiet pools. The eggs were most commonly attached in loose, irregular groupings to an aquatic moss (Fontinalis), and were positioned either singly or in compact, adherent clusters of 3-6 eggs. In a few instances, eggs were attached to the undersides of logs or other detritus. The terrestrial nests were placed in Fontinalis clumps around the margins of ponds, and females did not nest in Sphagnum mats even though they were abundant at many sites. Nests have been found elsewhere on land in or beneath logs (Petranka 1998). The ova are surrounded by a vitelline membrane and two jelly capsules. The outer capsule is adhesive, and each egg is attached by a short pedicel to the substrate (Petranka 1998). The diameters of the outer capsules of eggs collected by (Rabb 1956) were 2.5-3.4 mm and average 3.0 mm.

Females lay their eggs in January and February in the Carolinas (Bruce 1971). A female with 62 freshly laid eggs was found in late January in South Carolina (Rabb 1956), and another with 15 eggs near hatching was found in late March in North Carolina (Schwartz and Etheridge 1954). Eggs in early developmental stages can be found in southeastern Virginia from late February through early April (Wood and Rageot 1963).

Estimates of clutch sizes are based primarily on counts of eggs in the field. Wood and Rageot (1963) found from 6-92 eggs (mean = 37) in 35 aquatic nests in Virginia compared with 9-45 eggs (mean = 22) in eight terrestrial nests. Bruce (1971) found 22-29 mature ova in three females from one North Carolina site, and 42-60 (mean = 51) in eight from a second site. The embryos require 1-2 months to reach the hatching stages. Hatching occurs in late March and early April in the Carolinas (Bruce 1971, 2008).
Aquatic Life History: The larvae live in standing or sluggish water and feed on small invertebrates. They are often found in cover such as bottom debris, leaf litter and moss mats. Foard and Auth (1990) found that the diets of larvae and adults from Georgia were very similar, and that individuals tend to incorporate larger prey into the diet with age. Amphipods, isopods, chironomids, and ostracods were the most common prey, but small numbers of numerous other taxa were taken.

The larvae typically transform when 30-46 mm SVL, but a few individuals may transform when as small as 27 mm SVL (Petranka 1998). Bruce (1971) found that larvae in one North Carolina population grew an average of 15-16 mm SVL during the first year after hatching and 9-10 mm the following year. Most metamorphosed during late spring and summer about 25-28 months after hatching, although some transformed after only 13-16 months of growth. At a second site in North Carolina, the larval period lasted only 13-14 months, with larvae metamorphosing when around 38-46 mm SL (Bruce 2008). Larvae that were studied by Foard and Auth (1990) in Georgia transformed when 30-35 mm SVL.

Bruce (1971) found that most males in a North Carolina population matured sexually within a few months after transforming and reproduced the following autumn when about 33 months old. Sexual maturation occurred at 33-40 mm SVL. The small percentage of males that transformed 13-16 months after hatching first reproduced when 21 months old. Unlike males, most females in this population remained as juveniles for over 1 year after transforming and matured when 37-45 mm SVL. Most laid their first clutch when 4-years old.

At a second site in North Carolina, the larval period only lasted 13-16 months and males matured and bred that autumn within a few months after transforming. Females in this population produced their first clutch a year earlier when only 3-years old (Bruce 2008).
Terrestrial Life History: This species is essentially aquatic, but the adults are occasionally found near the margins of aquatic sites.
General Ecology
Population Ecology: Factors that regulate adult population size are unknown. The adults do not appear to be territorial, and it would be difficult for the aquatic adults to mark territories with chemical cues as is often the case for terrestrial plethodontids.
Adverse Environmental Impacts
Habitat Loss: The widespread historical draining and elimination of wetlands in the Southeast has undoubtedly resulted in many local populations being lost. Deforestation presumably has little direct effects on this largely aquatic species, but could have indirect effects associated with increased siltation of aquatic sites.
Status in North Carolina
NHP State Rank: S3S4
Global Rank: G5
Status in North Carolina: W5
Environmental Threats: The loss and degradation of wetlands in the Atlantic Coastal Plain poses the greatest threat to this species. From the 1950s–1970s the loss of wetlands in the Southeast was greater than in any other region of the country, with a net annual loss of 386,000 ac/yr (Hefner and Brown 1985). In North Carolina approximately 51% of all wetland acreage on the Coastal Plain has been lost, which has undoubtedly eliminated or adversely affected many local populations of the Many-lined Salamander. As of 2021, iNaturalist list only 16 observations of the species from throughout its entire range. It is uncertain to what extent this reflect major population declines or the difficulty of collecting the larvae and adults.

Photo Gallery for Stereochilus marginatus - Many-lined Salamander

2 photos are shown.

Recorded by: Eric Johnson
Bertie Co.
Comment: Cypress swamp
Recorded by: E. Corey and JCBeane (NCSM)
Pender Co.