Amphibians of North Carolina
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Plethodontidae Members:
NC Records

Plethodon chlorobryonis - Atlantic Coast Slimy Salamander


Taxonomy
Class: Amphibia Order: Caudata Family: Plethodontidae Subfamily: Plethodontinae
Taxonomic Comments: A group of wide-ranging large Plethodon species in the eastern US with a blackish ground color and varying levels of whitish or golden flecking, blotching, and spotting have traditionally been known as 'slimy salamanders' due to glutinous secretions that are produced from the tail. These were originally thought to represent a single wide-ranging species (the Slimy Salamander, Plethodon glutinosus), but were split into 16 species by Highton (Highton 1984, 1989; Highton and MacGregor 1983) and constitute the 'Plethodon glutinosus complex'. One (P. aureolus) was described in 1984 and the other (P. kentucki) was resurrected in 1983. The remainder were described by Highton (1989) and constitute a complex of geographically and genetically variable groups that are difficult to distinguishable from one another based on external phenotypic traits.

Highton (1989) analyzed geographic variation in protein patterns and split these into numerous species using an arbitrary genetic distance to define species. This resulted in a series of parapatric forms that show varying levels of gene exchange in contact zones. Frost and Hillis (1990) objected to splitting P. glutinosus into multiple species based solely on arbitrarily selected genetic distances and cited a variety of perceived problems, including several biases in estimating genetic distances. Data from studies using mitochondrial and nuclear sequence data (Fisher-Reid and Wiens 2011, Wiens et al. 2006) was used to justify keeping Highton's original taxonomy for the group. These studies sometimes relied on sequence data from a single representative individual of each species and did not carefully examine contact zones or examine levels of gene exchange between form, which Hillis (2019) argued is essential for making taxonomic decisions.

Joyce et al. (2019) analyzed multiple specimens from Alabama that represented three members of the P. glutinosus complex (P. glutinosus, P. grobmani, and P. mississippi) and concluded that these represent a single species of slimy salamander (P. glutinosus) rather than three as proposed by Highton (1989). They further argue that similar issues arise when multiple individuals have been used in studies: paraphyly is common place and the validity of several species is questionable (e.g., Smith et al. 2018, Wiens et al. 2006). To complicate matters further, members of the P. glutinosus complex show widespread evidence of historical or present gene exchange with members of the P. jordani complex (Weisrock et al. 2005). Joyce et al. (2019) recommended only recognizing three species within the P. glutinosus complex: P. aureolus, P. kentucki, and P. glutinosus. The latter would be treated as a geographically variable species that contains all of the remaining species that Highton recognized.

The taxonomic status of many members of the Plethodon glutinosus complex is clearly unresolved, and there may never be a complete resolution of the problem given that experts often embrace different taxonomic philosophies when interpreting geographic variation within a group. In addition, there is often widespread discordance in the lines of evidence used to delineate species. North Carolina may have as many as 6 members of the 16 species recognized by Highton, although two are of questionable status. These include P. aureolus, P. chattahoochee, P. chlorobryonis, P. cylindraceus, P. glutinosus and P. teyahalee. Here we continue to include all six of these forms in the North Carolina fauna, with the understanding that the taxonomic status of some may change in the future.
Species Comments:
Identification
Description: This is a relatively small member of the P. glutinosus complex that has small, slightly brassy white dorsal spots and abundant lateral white or yellowish spotting. Adults have a black to dark bluish black ground color, and the venter is grayish black and slightly lighter colored than the dorsum. The tail is rounded in cross-section and slightly longer than the body. The number of costal grooves averages 16. Sexually mature males have prominent circular-shaped mental glands and papillose cloacal lining. Beane et al. (2011) noted that the dorsal spotting is often greatly reduced or missing on North Carolina specimens.

The White-spotted Slimy Salamander (P. cylindraceus) comes into close geographic contact with the Atlantic Coast Slimy Salamander (P. chlorobryonis) from southeastern Virginia to western South Carolina near the boundary between the Piedmont and Coastal Plain. Highton and Peabody (2000) sampled populations along two transects in southeastern Virginia and northeastern North Carolina and found that there is a hybrid zone in both areas. These species can be separated to some extent using size and coloration. In addition to being smaller on average, P. chlorobryonis tends to have small, slightly brassy white dorsal spots and abundant lateral white or yellowish spotting, while P. cylindraceus tends to have larger dorsal spots that are whiter and with only moderately abundant lateral white spots. However, specimens often deviate substantially from these general trends. Highton (1989) noted that Piedmont populations of P. chlorobryonis in South Carolina are substantially larger than those in the Coastal Plain, so size may not always be helpful in identifying specimens collected near the border of the Piedmont and Coastal Plain, particularly if hybrids are present. A comprehensive molecular analysis of the contact zone in North Carolina is needed.
Online Photos:    Google
Observation Methods: Individuals can be found beneath surface cover such as logs year-round except during bouts of cold weather, and at night on the forest floor during favorable weather.
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 Atlantic Coast Slimy Salamander is most commonly found in bottomlands with hardwood or mixed pine-hardwood forests. It often occurs in the immediate vicinity of swamps or small streams, but generally outside of areas that experience frequent flooding. Lamb et al. (1998) surveyed the herpetofauna in the Lower Roanoke River floodplain in eastern North Carolina and found that this and other amphibians were largely absent from levee forests that were subjected to periodic flooding. Instead, they were found in ridge forests that were dominated by oaks, Sweetgum, and Loblolly Pine. In addition to using bottomland hardwoods, P. chlorobryonis has occasionally been found in Longleaf Pine forests or other pine-dominated forests where it presumably is restricted to moist microhabitats. However, most records are from hardwood forests.
See also Habitat Account for Coastal Plain Wet-Mesic Forests
Life History and Autecology
Breeding and Courtship: Courtship behavior has not been described, but is assumed to be very similar to that of P. cylindraceus since the two interbreed (see the description of courtship under the P. cylindraceus account).
Reproductive Mode: Most females presumably nest underground in natural cavities and guard their developing eggs through hatching. The only nest that has been reported was in a pile of damp paper cement bags in Virginia where a juvenile and four females in breeding condition were found (Wood and Rageot 1955). A cluster of seven eggs that were 5.0–5.5 mm in diameter was found within the pile of cement bags.
Terrestrial Life History: Almost all aspects of the life history of this species are undocumented and a comprehensive life history study is needed.
General Ecology
Adverse Environmental Impacts
Status in North Carolina
NHP State Rank: S5
Global Rank: G5
Environmental Threats: The major threat to this species is from the continuing loss of forests in the Coastal Plain due to urbanization, the conversion of forested lands to agricultural fields, and the replacement of diverse natural forests with pine monocultures with even-age harvesting.
Status Comments: Plethodon chlorobryonis has suffered major declines since European colonization due to the widespread loss of forests in the Coastal Plain associated with urbanization, the conversion of forested lands to agricultural fields, and the replacement of diverse natural forests with tree farms. This species is still locally abundant in many areas where mature forest stands are present. Highton (2003) reported a decline in all ten Atlantic Coast Slimy Salamander populations that he sampled prior to 1985 and re-sampled after 1995 under similar sampling conditions and with a similar search effort.

Photo Gallery for Plethodon chlorobryonis - Atlantic Coast Slimy Salamander

7 photos are shown.

Recorded by: R. Evans
Onslow Co.
Recorded by: Steve Hall
Beaufort Co.
Recorded by: Steve Hall
Beaufort Co.
Recorded by: Steve Hall
Beaufort Co.
Recorded by: Steve Hall and Harry LeGrand
Halifax Co.
Recorded by: E. Corey, J. Shimel, A. Burkhart, B. Brochers
New Hanover Co.
Recorded by: E. Corey, J. Shimel, A. Burkhart, B. Brochers
New Hanover Co.