Seepage salamander

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Seepage salamander
Desmognathus aeneus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Plethodontidae
Subfamily: Plethodontinae
Genus: Desmognathus
Species:
D. aeneus
Binomial name
Desmognathus aeneus
Brown & Bishop, 1947 [2]

The seepage salamander (Desmognathus aeneus) is a small, terrestrial species of salamander in the family Plethodontidae. It is endemic to the United States. They are found in small areas of Tennessee, North Carolina, Georgia, and Alabama. [3] Its natural habitats are temperate forests, intermittent rivers, and freshwater springs. It gets its name from the seepages around which it lives. It is very similar in its appearance and life history to the pygmy salamander (Desmognathus wrighti). These two species differ greatly from the other Desmognathus species. They are the smallest salamanders in the genus, measuring only 3–5 cm (1–2 in) in length. They are also the only two terrestrial, direct-developing Desmognathus species. However, the two species are not often seen to coexist, differing in distribution by elevation; although there are exceptions. The seepage salamander is currently listed as Near Threatened, with its numbers declining in most of states in which it is found. It is threatened by habitat loss, with logging having a major effect.

Contents

Description

The seepage salamander is a very small and slender salamander, ranging from 4.4–5.7 cm (1.75–2.25 in). The adults possess vomerine teeth. [2] The tail is terete and rounded. The seepage salamander has a pale dorsal stripe, with a wide, wavy to almost straight shape, and ranging in color from yellow or tan to reddish brown. [4] The stripe is sometimes flecked with a darker pigment. A mid-dorsal, dark line is also seen and is continuous with a Y-shaped mark on the head. There is a dark brown band on the sides, fading towards the belly. The underbelly is pale and is mottled with brown and white, but it may also be plain, with no other coloration. [4]

The seepage salamander is easily confused with the Pygmy Salamander (Desmognathus wrighti). These two species overlap in a small area of southern North Carolina. D. wrighti and D. aeneus are the smallest species in the genus Desmognathus and are the only terrestrial direct-developers, lacking a free-swimming larval stage. [5] They both have vomerine teeth, and similar tail length to total body length ratios; however, they have different patterns and coloration. [2] Seepage salamanders have a smoother top of the head. The mental glands are also shaped differently in the males. The pygmy salamander has a large, U-shaped mental gland while the seepage salamander's is small and kidney shaped.

General description and taxonomy

The seepage salamander is part of the genus Desmognathus and the family Plethodontidae. Like all other plethodontids, the seepage salamander is lungless and respires through its skin and the lining of its mouth. [4] They also have a naso-labial groove and a relatively immoveable lower jaw which allows them to force their way under objects. As with all species in Desmognathus, they have a pale line running diagonally from the eye to the angle of the jaw. This line may be hard to see in older, darker adults. Their hind legs are larger and stouter than the forelegs. Their body is short and stout and they are good jumpers, often used as an escape.

According to the phylogenetic tree, the seepage salamander branched deep within the tree of the Desmognathus species. D. aeneus is a sister group to all species of Desmognathus except D. wrighti, which is an outgroup. [6] D. aeneus and D. wrighti have distinct character differences from the rest of the Desmognathus species. They are the smallest species, direct-developers, and the most terrestrial, with all other species being semi-aquatic or aquatic. Since these two species branch the earliest, evolution has moved toward larger body size, lengthened larval periods, and more aquatic habitats within Desmognathus. [7]

Geographic distribution

Seepage salamanders get their name from the seepages where they are often found. However, they are also found near streams and under leaf litter, leaf mold, and rotten logs. [8] They are a terrestrial species.

Seepage salamanders are distributed in southeast Tennessee, southwest North Carolina, northern Georgia, and central to northern Alabama. They are found in Monroe and Polk counties in Tennessee; Fannin, Pickens, Towns, and Union counties in Georgia; Oconee County in South Carolina; and Cherokee, Clay, Graham, Macon, and Swain counties in North Carolina. In Alabama, they can be found in Calhoun, Clay, Cleburne, and Tallapoosa counties. [9] They also might be found in Cherokee, Chilton, Etowah, Hale, and Tuscaloosa counties in Alabama, but may be extirpated from these locales. [9]

Populations have a disjunct distribution and are highly localized. [8] There is an isolated colony in western Alabama, and one in northeastern Georgia. Populations are found at elevations ranging from 210–1,370 m (700–4,500 ft). However, in the colony in northeastern Georgia they can be found as low as 30 m (100 ft). [4]

Ecology

The seepage salamander does not experience much competition from other species of salamanders due to its habitat. Because it is a terrestrial salamander, it is not disturbed by the semi-aquatic and aquatic salamanders. [10] Almost all other Desmognathus species are found at closer distances to streams. The lack of competition also may be due to the fact that it is very secretive. It is seldom seen on the surface, which may be an anti-predatory response.

The only species of Desmognathus which would be found in the same habitat as the seepage salamander and create competitive pressure is the pygmy salamander (D. wrighti). However, the ranges of the two species rarely overlap. The pygmy salamander is found at higher elevations, while the seepage salamander is found at lower ones. The pygmy salamander is found on the border of North Carolina and Tennessee. The distribution range of the seepage salamander begins just below the pygmy salamander's range. However, there have been cases where the two species are found together. It has been observed that they coexist in Monroe County, Tennessee and it is possible that they coexist in Blount County, Tennessee. [11] Further studies are needed to determine their interactions and would aid in conservation efforts. [11]

Life history and behavior

Seepage salamanders are rarely seen on the surface even at night, despite being nocturnal. [10] The food sources consists mainly of arthropods, especially insect larvae and springtails. [12] Mites, spiders, earthworms, crustaceans, nematodes, myriapods, and snails have also been found to be eaten by seepage salamanders.

Life history

The seepage salamander is terrestrial and develop directly into juveniles, skipping the aquatic, larval stage. The length of time between fertilization and hatching is 68–75 days. [13] When eggs hatch, the juveniles clearly resemble the adults.

Oviposition occurs in April and May, with all eggs ready for deposition by the female being laid. [8] The eggs hatch in the late spring and summer. There have been some discrepancies about how long it takes for the eggs to hatch. Both males and females reach sexual maturation after two years. Harrison (1967) found that eggs hatched in 43–45 days, but Marks and Collazo found 68–75 days. [8] [13] This may be due to different incubation temperatures, but the difference has not been fully explored.

Courtship

There is little diversity within Plethodontidae in regards to mating. The mating process consists of courting behavior, the tail straddling walk, sperm deposition in the form of a spermatophore, and insemination. However, the seepage salamander differs in its courtship behavior.

As with all other plethodontids, pheromones are secreted by males and are used during the courtship process. Most species use a pulling or snapping behavior. However, only D. aeneus and D. wrighti use biting as a delivery mechanism. [14] These two species physically and directly restrain the females and bite them. The bites can last up to several hours. Then they release pheromones into the bite wounds. [14] Other plethodontids do not directly restrain the females when excreting pheromones.

Conservation

The seepage salamander is classified as Near Threatened by the IUCN because their range is not greater than 20,000 km2 and its habitat and population size is decreasing. [1] The isolation of the different population also increases susceptibility to declines. Seepage salamanders are on the verge of becoming classified as Vulnerable.

The species is in decline in Alabama and North Carolina, but is stable in South Carolina. [1] It is listed as in need of management in Tennessee.

Logging is a main source of decline within the species, particularly in Alabama. [15] Around half of the populations known in 1976 are now extinct. [16] Other forestry practices, like clear cutting also threaten seepage salamanders.

Most populations of seepage salamanders do not occur within protected areas. Therefore, to decrease vulnerability of populations to certain forestry practices, buffers should be set up in susceptible areas around seepages and streams. [1]

Related Research Articles

<span class="mw-page-title-main">Plethodontidae</span> Family of amphibians

Plethodontidae, or lungless salamanders, are a family of salamanders. Most species are native to the Western Hemisphere, from British Columbia to Brazil, although a few species are found in Sardinia, mainland Europe south of the Alps, and South Korea. In terms of number of species, they are by far the largest group of salamanders.

<span class="mw-page-title-main">Holbrook's southern dusky salamander</span> Species of amphibian

Holbrook's southern dusky salamander, previously known as just the southern dusky salamander, is a species of salamander endemic to the southeastern United States. Older sources often refer to it as the eared triton. Formerly abundant, it has precipitously declined since the 1960s.

<i>Desmognathus fuscus</i> Species of amphibian

Desmognathus fuscus is a species of amphibian in the family Plethodontidae. The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United States which form several distinct species, the southern dusky salamanders. The northern dusky salamander is the most widespread representative of its genus in Canada. It can be found in eastern North America from extreme eastern Canada in New Brunswick south to South Carolina. The size of the species' total population is unknown, but is assumed to easily exceed 100,000. The species' habitat differs somewhat geographically; dusky salamanders in the northern part of the range prefer rocky woodland streams, seepages, and springs, while those in the south favor floodplains, sloughs, and muddy places along upland streams. They are most common where water is running or trickling. They hide under various objects, such as leaves or rocks, either in or near water. Alternatively, they may enter burrows for protection. The dusky salamander lays its eggs close to water under moss or rocks, in logs, or in stream-bank cavities. The larval stage which follows is normally aquatic.

<span class="mw-page-title-main">Imitator salamander</span> Species of amphibian

The imitator salamander is a species of salamander in the family Plethodontidae. It is endemic to the Appalachian Mountains in the Eastern United States.

<span class="mw-page-title-main">Shovelnose salamander</span> Species of amphibian

The shovelnose salamander is a species of salamander in the family Plethodontidae. It is endemic to the United States.

<span class="mw-page-title-main">Ocoee salamander</span> Species of amphibian

The ocoee salamander is a species of salamander in the family Plethodontidae. This salamander has a variety of colors and patterns, and got its name from Tennessee state wildflower. Its natural habitats are temperate forests, rivers, intermittent rivers, freshwater springs and wet rocks in mountainous areas of the Southeastern United States. It was first described by Nicholls in 1949. They are territorial and feed on small invertebrates. It is widely distributed in the southeastern United States and is listed as "Least Concern" by the International Union for Conservation of Nature.

<span class="mw-page-title-main">Blackbelly salamander</span> Species of amphibian

The blackbelly salamander is a species of salamander in the family Plethodontidae. It is endemic to the United States. Its natural habitats are rivers, intermittent rivers, and freshwater springs. It is threatened by habitat loss.

The black mountain salamander is a species of salamander in the family Plethodontidae.

<span class="mw-page-title-main">Pygmy salamander</span> Species of amphibian

The pygmy salamander is a species of salamander in the family Plethodontidae. It is endemic to the United States in the southern Appalachians in North Carolina and Tennessee. Desmognathus wrighti is a member of the family Plethodontidae and is commonly known as the pygmy salamander. As the name suggest the pygmy salamander is the smallest of the nineteen species in the genus Desmognathus. D. wrighti undergoes direct development and does not have a free-living larval stage. Only two other taxa in Desmognathus, D. aeneus and D. organi, exhibit direct development along with the pygmy salamander. In the genus Desmognathus, body size, habitat preferences, and patterns used by males during courtship are quite variable. D. wrighti courtship is noted by the male biting and seizing its partner in order to provide them with a chemical stimulus. The pygmy salamander can be found in the southern Appalachians of the United States in western North Carolina and eastern Tennessee. Geographical distribution of the Desmognathus wrighti is fragmented and the highest abundance of the species can be found at high elevations in spruce and fir tree forest.

<span class="mw-page-title-main">Three-lined salamander</span> Species of amphibian

The three-lined salamander is a species of salamander in the family Plethodontidae. It is endemic to the south-eastern United States. Like other Plethodontidae species, E. guttolineata captures prey via tongue projection.

<span class="mw-page-title-main">Junaluska salamander</span> Species of amphibian

The Junaluska salamander is a species of lungless salamander native to the south-eastern United States. It was first described by David M. Sever, Harold M. Dundee, and Charles D. Sullivan who found the species in the range from the Cheoah River, Santeetlah Creek, and Tululah Creek in Graham County of North Carolina. Adults of this species can be found near large, rocky streams and on rainy nights on roads in the areas specified. The salamander is characterized by brownish-yellow coloration with a series of small dots along the body and a robust build compared to the other salamanders in Eurycea. The Junaluska salamander's breeding habits tend to be in large streams where the eggs are laid and attached to the bottom of rocks in the streams where they are found. According to the overall conservation listing for IUCN, this species is listed as Vulnerable. Conservation acts are important in both North Carolina and Eastern Tennessee, since the population of this species in each state is so small.

<span class="mw-page-title-main">Blue Ridge two-lined salamander</span> Species of amphibian

The Blue Ridge two-lined salamander is a species of salamander in the family Plethodontidae, endemic to the United States. This species is found in the southern Appalachian Mountains, mostly south of Virginia. To the north is a similar salamander, Eurycea bislineata, or the northern two-lined salamander. Its genus, Eurycea contains 33 species and includes taxa that have either a metamorphic life cycle or larval-form paedomorphosis. In species that metamorphose, there can be within-and among-population variation in larval life-history characteristics, e.g., duration of the larval period and size at metamorphosis. Intraspecific geographic variation in species of Eurycea has been attributed to several factors: temperature, stream order and productivity of the larval habitat.

<span class="mw-page-title-main">Red-cheeked salamander</span> Species of amphibian

The red-cheeked salamander, also known as the Jordan's salamander, Jordan's redcheek salamander, or Appalachian woodland salamander, is a species of salamander in the family Plethodontidae. It is endemic to the Appalachian Mountains in the eastern United States.

<span class="mw-page-title-main">Webster's salamander</span> Species of amphibian

The Webster's salamander is a species of salamander in the family Plethodontidae. It is endemic to the southeast United States, in patchy and disjunct lowland subpopulations ranging from South Carolina to Louisiana. Its natural habitat is mixed mesophytic temperate forests, in association with rocky streams and outcrops.

<span class="mw-page-title-main">Weller's salamander</span> Species of amphibian

Weller's salamander is a species of salamander in the family Plethodontidae. This species in endemic to the southeastern mountain range of the United States. It is mainly found in North Carolina near Grandfather Mountain. The salamanders have a unique metallic spotting which distinguishes them from other Plethodon species and other salamanders in the area. They mainly inhabit cool forests with rocky areas.

<span class="mw-page-title-main">Many-lined salamander</span> Species of amphibian

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<span class="mw-page-title-main">Green salamander</span> Species of amphibian

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<span class="mw-page-title-main">Northern pygmy salamander</span> Species of amphibian

The northern pygmy salamander is a terrestrial species of salamander in the family Plethodontidae and genus Desmognathus. Along with the southern pygmy and the seepage salamander, these are some of the smallest salamander species in North America and can be found in higher elevations in the southern Appalachians.

The flat-headed salamander is a species of salamander in the family Plethodontidae. It is endemic to the state of Virginia in the United States.

References

  1. 1 2 3 4 Geoffrey Hammerson, Julian Harrison (2004). "Desmognathus aeneus". IUCN Red List of Threatened Species . 2004: e.T59243A11905725. doi: 10.2305/IUCN.UK.2004.RLTS.T59243A11905725.en . Retrieved 16 November 2021.
  2. 1 2 3 Brown, W. C., and S. C. Bishop. 1947. A new species of Desmognathus from North Carolina. Copeia 1947: 163-166.
  3. ↑ Frost, Darrel R. (2014). "Desmognathus aeneus Brown and Bishop, 1947". Amphibian Species of the World: an Online Reference. Version 6.0. American Museum of Natural History. Retrieved 1 March 2015.
  4. 1 2 3 4 Conant, R. and Collins, J. 1998. Peterson Field Guides: Reptiles and Amphibians (Eastern/Central North America). Houghton Mifflin Company, New York.
  5. ↑ Hining, K.J., Bruce, R.C. 2005. Population Structure and Life History Attributes of Syntopic Populations of the Salamanders Desmognathus aeneus and Desmognathus wrighti (Amphibia: Plethodontidae) Southeastern Naturalist 4: 679-688.
  6. ↑ Kozak, K.H., Bonett, A.L., Harmon, L.J., 2005. Phylogenetic Analysis of Ecomorphological Divergence, Community Structure, and Diversification Rates in Dusky Salamanders (Plethodontidae: Desmognathus). Evolution 59:2000-2016.
  7. ↑ Titus, T. A. and Larson, A. 1996. Molecular phylogenetics of desmognathine salamanders (Caudata: Plethodontidae): a reevaluation of evolution in ecology, life history, and morphology. Systematic Biology, 45(4), 451-472.
  8. 1 2 3 4 Harrison, J. (1967). "Observations on the life history, ecology and distribution of Desmognathus aeneus aeneus Brown and Bishop". American Midland Naturalist. 77 (2): 356–370. doi:10.2307/2423347. JSTOR   2423347.
  9. 1 2 NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: April 25, 2011 )
  10. 1 2 Hairston, N.G. Sr. 1986. Species packing in Desmognathus salamanders: experimental demonstration of predation and competition. Am. Nat. 127:266-291
  11. 1 2 Reynolds, R.G., Niemiller, M.L., and Pasachnik. 2011. Occurrence of pygmy salamanders (Desmognathus wrighti) in Monroe County, Tennessee. Journal of the Tennessee Academy of Science 86(2):53–55
  12. ↑ Donovan, L.A. and G.W. Folkerts. 1972. Foods of the seepage salamander, Desmognathus aeneus Brown and Bishop. Herpetologica 28:35–37.
  13. 1 2 Marks, S.B., Collazo, A. 1998. Direct Development in Desmognathus aeneus (Caudata: Plethodontidae): A Staging Table. Copeia 3: 637-648.
  14. 1 2 Promislow, D. E. L. 1987. Courtship behavior of a plethodontid salamander, Desmognathus aeneus. J. Herpetol. 21:298-306.
  15. ↑ Folkerts, G.W. 1968. The genus Desmognathus Baird (Amphibia: Plethodontidae) in Alabama. Ph.D. dissertation. Auburn University, Auburn, Alabama.
  16. ↑ Harrison, J. 2011. Desmognathus aeneus: Seepage Salamander. AmphibiaWeb. Berkeley, California. http://amphibiaweb.org/>
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