The seepage salamander (''Desmognathus aeneus'') is a small, terrestrial species of

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

in the family

Plethodontidae Plethodontidae, or lungless salamanders, are a family of salamanders. With over 500 species, lungless salamanders are by far the largest family of salamanders in terms of their diversity. Most species are native to the Western Hemisphere, from B ...

. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the United States. They are found in small areas of Tennessee, North Carolina, Georgia, and Alabama. 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 ''Desmognathus'' is a genus of lungless salamanders in the family Plethodontidae known as dusky salamanders. They range throughout the eastern United States as far west as Texas, and north to southeastern Canada. Characteristics Species of th ...

'' species. They are the smallest salamanders in the genus, measuring only 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 A near-threatened species is a species which has been Conservation status, categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature (IUCN) as that may be vulnerable to Endangered species, endangerment in the ne ...

, 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.

Description

The seepage salamander is a very small and slender salamander, ranging from . The adults possess

vomer The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms ...

ine teeth.Brown, W. C., and S. C. Bishop. 1947. A new species of ''Desmognathus'' from North Carolina. ''Copeia'' 1947: 163-166. The tail is

terete Terete is a term in botany used to describe a cross section (geometry), cross section that is circular, or like a distorted circle, with a single surface wrapping around it.Lichen Vocabulary, Lichens of North America Information, Sylvia and S ...

and rounded. The seepage salamander has a pale

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

stripe, with a wide, wavy to almost straight shape, and ranging in color from yellow or tan to reddish brown.Conant, R. and Collins, J. 1998. ''Peterson Field Guides: Reptiles and Amphibians (Eastern/Central North America)''. Houghton Mifflin Company, New York. 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. 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.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. They both have vomerine teeth, and similar tail length to total body length ratios; however, they have different patterns and coloration. 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

. Like all other plethodontids, the seepage salamander is lungless and respires through its skin and the lining of its mouth. 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 A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...

, 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 Outgroup may refer to: * Outgroup (cladistics), an evolutionary-history concept * Outgroup (sociology) In social psychology and sociology, an in-group is a social group to which a person psychologically identifies as being a member. By cont ...

.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. ''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''.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.

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 Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituen ...

, leaf mold, and rotten logs. They are a terrestrial species. Seepage salamanders are distributed in southeast

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

, southwest

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

, northern

Georgia Georgia most commonly refers to: * Georgia (country), a country in the South Caucasus * Georgia (U.S. state), a state in the southeastern United States Georgia may also refer to: People and fictional characters * Georgia (name), a list of pe ...

, and central to northern

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

. They are found in

Monroe Monroe or Monroes may refer to: People and fictional characters * Monroe (surname) * Monroe (given name) * James Monroe, 5th President of the United States * Marilyn Monroe, actress and model Places United States * Monroe, Arkansas, an unincorp ...

and

Polk DNA polymerase kappa is a DNA polymerase that in humans is encoded by the ''POLK'' gene. It is involved in translesion synthesis DNA repair is a collection of processes by which a cell (biology), cell identifies and corrects damage to the ...

counties in Tennessee; Fannin, Pickens,

Towns A town is a type of a human settlement, generally larger than a village but smaller than a city. The criteria for distinguishing a town vary globally, often depending on factors such as population size, economic character, administrative stat ...

, and Union counties in Georgia; Oconee County in

South Carolina South Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders North Carolina to the north and northeast, the Atlantic Ocean to the southeast, and Georgia (U.S. state), Georg ...

; and

Cherokee The Cherokee (; , or ) people are one of the Indigenous peoples of the Southeastern Woodlands of the United States. Prior to the 18th century, they were concentrated in their homelands, in towns along river valleys of what is now southwestern ...

Clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

Graham Graham or Graeme may refer to: People * Graham (given name), an English-language given name * Graham (surname), an English-language surname * Graeme (surname), an English-language surname * Graham (musician) (born 1979), Burmese singer * Clan ...

, Macon, and

Swain Swain, Swains or Swain's may refer to: Places * Swain Islands, Antarctica * Swain's Island (Newfoundland and Labrador), Canada * Swains Island, an atoll in the Tokelau chain, American Samoa * Swain County, North Carolina, United States * Swains ...

counties in North Carolina. In Alabama, they can be found in

Calhoun John C. Calhoun (1782–1850) was the 7th vice president of the United States. Calhoun can also refer to: Surname * Calhoun (surname) Inhabited places in the United States *Calhoun, Georgia * Calhoun, Illinois *Calhoun, Kentucky * Calhoun, Louis ...

, Cleburne, and Tallapoosa counties.NatureServe. 2010. NatureServe Explorer: An online encyclopedia of life eb application Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: April 25, 2011 ) They also might be found in

, Chilton, Etowah, Hale, and

Tuscaloosa Tuscaloosa ( ) is a city in and the county seat of Tuscaloosa County, Alabama, Tuscaloosa County in west-central Alabama, United States, on the Black Warrior River where the Gulf Coastal Plain, Gulf Coastal and Piedmont (United States), Piedm ...

counties in Alabama, but may be extirpated from these locales. Populations have a

disjunct distribution In biology, a taxon with a disjunct distribution is one that has two or more groups that are related but considerably separated from each other geographically. The causes are varied and might demonstrate either the expansion or contraction of a s ...

and are highly localized. There is an isolated colony in western Alabama, and one in northeastern Georgia. Populations are found at elevations ranging from . However, in the colony in northeastern Georgia they can be found as low as .

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.Hairston, N.G. Sr. 1986. Species packing in ''Desmognathus'' salamanders: experimental demonstration of predation and competition.'' Am. Nat''. 127:266-291 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.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 Further studies are needed to determine their interactions and would aid in conservation efforts.

Life history and behavior

Seepage salamanders are rarely seen on the surface even at night, despite being nocturnal. The food sources consists mainly of

arthropods Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...

, especially insect larvae and

springtails Springtails (class Collembola) form the largest of the three lineages of modern Hexapoda, hexapods that are no longer considered insects. Although the three lineages are sometimes grouped together in a class called Entognatha because they have in ...

.Donovan, L.A. and G.W. Folkerts. 1972. Foods of the seepage salamander, ''Desmognathus aeneus'' Brown and Bishop. ''Herpetologica'' 28:35–37.

Mites Mites are small arachnids (eight-legged arthropods) of two large orders, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari. However, most recent genetic analyses do not recover the two as eac ...

spiders Spiders (order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species di ...

earthworms An earthworm is a soil-dwelling terrestrial animal, terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (biology), class (or subclass (biology), subclass, depending on ...

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

nematodes The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (he ...

myriapods Myriapods () are the members of subphylum Myriapoda, containing arthropods such as millipedes and centipedes. The group contains about 13,000 species, all of them terrestrial. Although molecular evidence and similar fossils suggests a diversifi ...

, and

snails A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial molluscs, terrestrial pulmonate gastropod molluscs. However, the common name ''snail'' is also used for most of the members of the molluscan class Gas ...

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 Fertilisation or fertilization (see American and British English spelling differences#-ise, -ize (-isation, -ization), spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give ...

and hatching is 68–75 days.Marks, S.B., Collazo, A. 1998. Direct Development in ''Desmognathus aeneus'' (Caudata: ''Plethodontidae''): A Staging Table. ''Copeia'' 3: 637-648. When eggs hatch, the juveniles clearly resemble the adults.

Oviposition The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typica ...

occurs in April and May, with all eggs ready for deposition by the female being laid. 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. 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 A spermatophore, from Ancient Greek σπέρμα (''spérma''), meaning "seed", and -φόρος (''-phóros''), meaning "bearing", or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especiall ...

, and

insemination Insemination is the introduction of sperm (in semen) into a female or hermaphrodite's reproductive system in order to fertilize the ovum through sexual reproduction. The sperm enters into the uterus of a mammal or the oviduct of an oviparous (eg ...

. 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. 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.Promislow, D. E. L. 1987. Courtship behavior of a plethodontid salamander, ''Desmognathus aeneus. J. Herpetol.'' 21:298-306. Other plethodontids do not directly restrain the females when excreting pheromones.

Conservation

The seepage salamander is classified as

by the

IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...

because their range is not greater than 20,000 km² and its habitat and population size is decreasing. 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. It is listed as in need of management in Tennessee. Logging is a main source of decline within the species, particularly in Alabama.Folkerts, G.W. 1968. The genus Desmognathus Baird (Amphibia: ''Plethodontidae'') in Alabama. Ph.D. dissertation. Auburn University, Auburn, Alabama. Around half of the populations known in 1976 are now extinct.Harrison, J. 2011. ''Desmognathus aeneus'': Seepage Salamander. ''AmphibiaWeb''. Berkeley, California. http://amphibiaweb.org/> 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.

References

{{Taxonbar, from=Q508932 Desmognathus Endemic amphibians of the United States Taxonomy articles created by Polbot Amphibians described in 1947 Taxa named by Walter Creighton Brown