Plethodon kentuckiCumberland Plateau Salamander

Geographic Range

Cumberland Plateau salamanders (Plethodon kentucki) are a native nearctic species, found primarily in the Cumberland Plateau of the United States. They have populations throughout eastern Kentucky, as well as in West Virginia in the western region of the New and Kanawha Rivers, and in southeastern Virginia in the counties of Russell and Washington counties. Cumberland Plateau salamanders also inhabit northeastern Tennessee. (Highton and MacGregor, 1983; Lannoo, 2005; Marvin, 2001)

Habitat

Cumberland Plateau salamanders inhabit the leaf litter of forested areas. They are found under rocks, logs, and in crevices beneath exposed roots of living trees. On west-facing slopes in mountainous terrain, they more commonly inhabit rock crevices, as well as sandstone and shale outcrops. Female salamanders lays eggs in underground nooks. Habitat elevation is dependent upon the region and ranges from 197 to 1,265 m. (Lannoo, 2005; Petranka, 2010)

  • Range elevation
    197 to 1265 m
    646.33 to 4150.26 ft

Physical Description

Cumberland Plateau salamanders are black with small white dorsal spots visible from both the dorsal and lateral view. These salamanders have light grey or white chins and throats which are larger on males during mating season, due to the presence of a round mental gland. Their ventral sides are a uniform slate gray color. Adult male salamanders range in snout-vent length (SVL) from 48 to 52 mm. They measure about 48mm by the time they reach sexual maturity, after between 3 to 5 years. Adult female salamanders are slightly larger; their SVL ranges from 52 to 64 mm, reaching sexual maturity at 52 mm, after 4 to 5 years.

Adult masses range from 2.0 to 5.1 g. Newly-hatched salamanders have an average SVL of 14 to 15 mm and a mass of 0.08 to 0.10 g. Emerging hatchlings resemble adults, but with fewer dorsal and lateral spots.

Cumberland Plateau salamanders have bilateral symmetry and a smaller body form when compared to closely-related salamanders of the same family, Plethodontidae. These salamanders are ectothermic, relying on environmental temperatures to regulate their metabolic rates. (Gibbons and Mitchell, 2010; Marvin, 1996; Marvin, 2001; Mittleman, 1951; Petranka, 2010)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range mass
    2 to 5.1 g
    0.07 to 0.18 oz
  • Range length
    48 SVL to 64 SVL mm
    to in

Development

Female Cumberland Plateau salamanders return to their burrows to lay eggs. Eggs hatch approximately three months after being fertilized and laid. Newly-hatched salamanders have a snout-vent length (SVL) of 14 to 15 mm and a mass of 0.08 to 0.10 g. Emerging hatchlings resemble adults, but with fewer dorsal and lateral spots. An incomplete metamorphosis occurs as hatchlings grow into adults. Hatchlings live off of their hatched egg yolks for several days. They remain near or on top of their mother for the period of yolk absorption, which can last several weeks. They remain in the burrow in which they were laid for about 8 to 9 months before going aboveground. Aboveground growth occurs at rates of 15 mm the first year, 10 mm the second year, and 6 mm the third year. Male salamanders reach sexual maturity between 3 and 4 years, while female salamanders reach sexual maturity between 4 and 5 years. By the time they are sexually mature, males reach snout-vent lengths of 48 to 52 mm, while sexually mature females range in SVL from 52 to 65 mm. Like other salamanders, Cumberland Plateau salamanders exhibit indeterminate growth. (Altig and McDiarmid, 2015; Gibbons and Mitchell, 2010; Marvin, 1996; Marvin, 2009; Petranka, 2010)

Reproduction

Cumberland Plateau salamanders breed seasonally from July to October. During mating season, males develop a mental gland containing a pheromone that can alter the behavior of females. Male salamanders initiate courtship by nose-tapping female salamanders. Male salamanders then engage in a foot dance while remaining stationary. They do this by raising one fore- and hind-limb one side at a time. Males nudge and then tap the snouts of females with their mental glands. Males deliver pheromones by scratching the dorsal area of females with their claws, then rubbing their mental glands over the scratched area.

Females demonstrate receptiveness by placing their chin on the dorsal side of male tails and initiating a tail-straddle walk. A tandem forward walk is initiated by both sexes near the end of the tail-straddle walk. Males undulate the base of their tails against the chins of females. Males then lower their vents near the substrate, quickly undulate their tails, and deposit a single spermatophore. After deposition, males stop undulating their tail, raise their vents and swing their tails laterally while moving forward, leading the females over their spermatophores. Once over the spermatophore, females lower their vents and pick up the spermatophore.

Once females receive a spermatophore, they quickly abandon their mate. Eggs are fertilized internally after females have received a spermatophore. Males ingest the remaining spermatophore. Females retreat and remain with their eggs until they hatch. Male salamanders can mate multiple times in one season while females mate just once. (Dyal, 2006; Petranka, 2010)

The mating season for Cumberland Plateau salamanders goes from May to July. Sexes breed at different intervals. Female salamanders reach reproductive maturity at 4 to 5 years of age and breed biennially or less. This breeding cycle allows time for females to accumulate sufficient energy reserves. These reserves are needed to produce and brood eggs because females do not forage until hatchlings are more independent.

Male salamanders reach reproductive maturity at 3 to 4 years and breed annually. Eggs are fertilized internally after females have received a spermatophore. Female salamanders then return to their burrows to lay their eggs. Female salamanders remain in their burrows with eggs for 2 to 3 months, until eggs have hatched. Hatchlings weigh 0.08 to 0.10 g and remain in their burrows for 8 to 11 months. When kept in laboratory conditions, female salamanders produce 9 to 12 offspring. Male and female salamanders are iteroparous, mating many times in their lives. (Marvin, 1996; Marvin, 2009; Petranka, 2010)

  • Breeding interval
    Female Cumberland Plateau salamanders breed biennially or less, while male salamanders breed yearly.
  • Breeding season
    Mating season for the Cumberland Plateau Salamander ranges from May to July, with eggs hatching August to October.
  • Range number of offspring
    9 to 12
  • Range time to hatching
    2 to 3 months
  • Range time to independence
    8 to 11 months
  • Range age at sexual or reproductive maturity (female)
    4 to 5 years
  • Range age at sexual or reproductive maturity (male)
    3 to 4 years

Female Cumberland Plateau salamanders receive spermatophores by lowering their vents over a spermatophore. Eggs are fertilized internally and laid in burrows prepared by females. Female salamanders remain with their eggs until they hatch, generally 2 to 3 months. During this time they never leave to forage.

Once eggs have hatched, mothers provide protection for their hatchlings for several weeks. Hatchlings burrow underground for the winter and emerge the following summer as juveniles at approximately 8 months of age. Females leave to forage but return to their hatchlings to provide protection until they emerge from their burrows. (Altig and McDiarmid, 2015; Marvin, 2009; Marvin and Hutchison, 2010)

  • Parental Investment
  • female parental care
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female
  • pre-independence
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

No specific information has been reported about maximum or expected longevity in the wild for Cumberland Plateau salamanders. Marvin (2001) found that annual survivorship for Cumberland Plateau salamanders in their natural habitat is 48% for two-year-olds, 68% for three-year-olds and 72 to 92% for adults. Cumberland Plateau salamanders are not kept in captivity.

Lannoo (2005) stated that northern slimy salamanders (Plethodon glutinosus) are known to live for over 20 years in the wild, which may be comparable to Cumberland Plateau salamanders. (Lannoo, 2005; Marvin, 2001)

Behavior

Cumberland Plateau salamanders are social and nocturnal, living on the ground (in leaf litter) or in burrows. Salamanders are motile, with limited activity in winter months. They are most active from dusk to dark with decreasing activity throughout the night. They can often be located under the same cover as conspecific salamanders. When threatened, salamanders will often retreat to escape the threat. In the instance that they are unable to retreat, they will emit secretions, bite, lunge, or drop their tail in order to escape from the predator. This voluntary loss of their tails is known as autotomy, and is an effective defense against predators.

Cumberland Plateau salamanders are less active in cooler winter months, but they are not believed to truly hibernate. Adults have been found in leaf litter in February, suggesting year-round activity if warm bouts allow it. (Lannoo, 2005; Marvin, 1998; Marvin, 2001)

Home Range

Cumberland Plateau salamanders are sedentary, never traveling further than 2 m from their hatching place. They remain in this home range for the entirety of their lives. Average home range for adult salamanders is 5.6m^2 and 1.5m^2 for juvenile salamanders.

Laboratory experiments suggest that Cumberland Plateau salamanders occasionally defend a territory against members of the same genus, but territory size was not quantified. Cumberland Plateau salamanders were described as "appeasers," meaning that they avoid confrontation and direct aggression if possible. In manipulated laboratory situations, these salamanders were more territorial as density increased and protective cover declined. (Baecher and Richter, 2018; Lannoo, 2005; Marvin, 1998; Marvin, 2001)

Communication and Perception

Cumberland Plateau salamanders communicate through chemical, visual, and tactile means. Female Cumberland Plateau salamanders emit pheromones when mating season approaches to signal males of their readiness. Males respond by tapping their mental gland, located under their chins, along the dorsal side of females. Both sexes can emit a noxious secretion from glands in their tails to deter small predators. (Dyal, 2006; Marvin, 1998; Petranka, 2010)

Food Habits

Cumberland Plateau salamanders forage on the forest floor in search of food. Because of their limited home range, they are opportunists. Their expansive diet includes ants, caterpillars, centipedes, springtails, spiders, beetles, true flies, mayflies, mites, snails, false scorpions, cockroaches, and termites. These salamanders catch prey by using rapid tongue movements. They forage primarily around dusk. (Gibbons and Mitchell, 2010; Marvin, 1998)

  • Animal Foods
  • insects
  • terrestrial non-insect arthropods
  • mollusks

Predation

No predators have been reported for Cumberland Plateau salamanders. In the presence of a predator, salamanders retreat into underground burrows or hide underneath cover, such as rocks or rotting logs. If threatened, salamanders may bite or lunge at predators. When attacked, they emit copious amounts of noxious mucous and, as a last resort, can drop their tail in order to escape. (Gibbons and Mitchell, 2010; Lannoo, 2005; Marvin, 1998; Marvin, 2001)

Ecosystem Roles

Cumberland Plateau salamanders are assumed to be prey for snakes and birds. These salamanders generally feed on springtails, spiders, beetles, flies, mites, snails, cockroaches, termites and mayflies. No parasites have been reported for Cumberland Plateau Salamanders. Chigger attachment in the snouts of other members of the family Plethodontidae has been reported, so it is possible that this occurs in Cumberland Plateau salamanders as well. (Gibbons and Mitchell, 2010; Marvin, 1998)

Economic Importance for Humans: Positive

There are no positive economic effects of Cumberland Plateau salamanders on humans.

Economic Importance for Humans: Negative

There are no negative economic effects of the Cumberland Plateau salamander on humans.

Conservation Status

The IUCN Red List lists Cumberland Plateau salamanders as a species of "Least Concern." No special status was listed for these salamanders on the US Federal List, CITES, and the State of Michigan list.

Threats to Cumberland Plateau salamanders include habitat fragmentation and deforestation. The harvesting of mature hardwoods has a negative impact on Cumberland Plateau salamanders. Harvesting hardwoods removes canopy cover that maintains adequate soil moisture levels. These salamanders require cool, moist soil in order to survive.

Because Cumberland Plateau salamanders currently maintain a high degree of genetic diversity, no conservation practices are in place. (Baecher and Richter, 2018; Kuchta, et al., 2016; Petranka, 2010)

Contributors

Angie Holmes (author), Radford University, Lauren Burroughs (editor), Radford University, Layne DiBuono (editor), Radford University, Lindsey Lee (editor), Radford University, Karen Powers (editor), Radford University, Galen Burrell (editor).

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

female parental care

parental care is carried out by females

fertilization

union of egg and spermatozoan

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

fossorial

Referring to a burrowing life-style or behavior, specialized for digging or burrowing.

indeterminate growth

Animals with indeterminate growth continue to grow throughout their lives.

insectivore

An animal that eats mainly insects or spiders.

internal fertilization

fertilization takes place within the female's body

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

molluscivore

eats mollusks, members of Phylum Mollusca

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pheromones

chemicals released into air or water that are detected by and responded to by other animals of the same species

polygynous

having more than one female as a mate at one time

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

terrestrial

Living on the ground.

visual

uses sight to communicate

References

Altig, R., R. McDiarmid. 2015. Handbook of Larval Amphibians of the United States and Canada. Ithaca, NY: Cornell University Press.

Anthony, C., J. Mendelson III, R. Simons. 1994. Differential parasitism by sex on Plethodontid salamanders and histological evidence for structural damage to the nasolabial groove. American Midland Naturalist, 2/132: 302-307.

Baecher, J., S. Richter. 2018. Environmental gradients in old-growth Appalachian forest predict fine-scale distribution, co-occurrence, and density of woodland salamanders. Ecology and Evolution, 8/24: 12940-12952.

Bailey, J. 1992. An Ecological Study of the Cumberland Plateau Salamander, Plethodon kentucki Mittleman, in West Virginia (Master’s thesis). Huntington, West Virginia: Marshall University.

Bowers, R. 2013. Filling in the Gaps in Phenology and Life History of the Cumberland Plateau Salamander (Plethodon kentucki) (Master's thesis). Huntington, West Virginia: Marshall University.

Carr, D. 1996. Morphological variation among species and populations of salamanders in the Plethodon glutinous complex. Herptologica, 52/1: 56-65.

Dyal, L. 2006. Novel courtship behaviors in three small eastern Plethodon species. Journal of Herpetology, 40/1: 55-65.

Feder, M. 1983. Integrating the ecology and physiology of plethodontid salamanders. Herpetologica, 39/3: 291-310.

Gibbons, W., J. Mitchell. 2010. Salamanders of the Southeast. Athens, GA: The University of Georgia Press.

Highton, R., J. MacGregor. 1983. Plethodon kentucki Mittleman: A valid species of Cumberland Plateau woodland salamander. Herpetologica, 39: 3.

Hutton, J., S. Price, S. Richter. 2017. The diet of the Cumberland Plateau salamander (Plethodon kentucki) in an old growth forest of southeastern Kentucky. American Midland Naturalist, 178/1: 144-150.

Kuchta, S., A. Brown, P. Converse, R. Highton. 2016. Multiculocus phytogeography and species delimitation in the Cumberland Plateau salamander, Plethodon kentucki: Incongruence among data sets and methods. PLoS ONE, 11/3: 1-20.

Lannoo, M. 2005. Amphibian Declines: The Conservation Status of United States Species. Los Angeles, CA: University of California Press.

Marvin, G. 2001. Age, growth, and long-term site fidelity in the terrestrial Plethodontid salamander Plethodon kentucki. Copeia, 2001/1: 108-117.

Marvin, G. 1998. Territorial behavior of the Plethodontid salamander Plethodon kentucki: Influence of habitat structure and population density. Oecologia, 114/1: 133-144.

Marvin, G., V. Hutchison. 2010. Courtship behavior of the Cumberland Plateau woodland salamander, Plethodon kentucki (Amphibia: Plethodontidae). Ethology, 102/1: 285-303.

Marvin, G. 1996. Life history and population characteristics of the salamander Plethodon kentucki with a review of Plethodon life histories. American Midland Naturalist, 136/2: 385-400.

Marvin, G. 2009. Sexual and seasonal dimorphism in the Cumberland Plateau woodland salamander, Plethodon kentucki (Caudata: Plethodontidae). Copeia, 2009/2: 1-5.

Mittleman, M. 1951. American Caudata. VII. Two new salamanders of the genus Plethodon. Herpetologica, 7/3: 105-112.

Petranka, J. 2010. Salamanders of the United States and Canada. Washington, D.C.: The Smithsonian Institution.