Plethodon jordani

Geographic Range

Plethodon jordani ranges from southwestern Virginia to extreme northeastern Georgia. Plethodon jordani has been collected from elevations of 213 to 1951 m, but populations are usually constrained to elevations above 600 m.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Plethodon jordani is restricted to cool, mesic forests. Jordan's salamanders are found in areas with high annual precipitation from deep mountain gorges to the ridgeline in suitable habitat. Populations occur at their lowest elevations in the southern portions of their range. Individuals are most often found on the forest floor during the night when they emerge to forage, they are sometimes found under logs and rocks during the day, although they mostly remain underground when not foraging. Jordan's salamanders are most abundant in red spruce ( Picea rubens ) - Fraser fir ( Abies fraseri ) forest but are also found on hardwood-covered ridges. The forest floor where this species is most abundant is covered with a heavy layer of moss with only a little soil over a mass of large boulders.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• forest forest
• mountains mountains

Physical Description

Plethodon jordani is a large species of Plethodon that varies in color according to locality. The dorsal color varies from slate gray to bluish black and the back usually lacks both red pigments and white spots. Depending on geographic location, the adults may be unmarked or have red cheeks (Great Smoky Mountains, Tennessee), red legs (Nantahala and Tusquitee mountains and on Cheoah Mountain, North Carolina), reddish frosting on the back (extreme northwestern South Carolina and on Fishhawk Mountain, North Carolina), or gold frosting on the back in the southernmost part of their range. Jordan's salamanders have sixteen costal grooves. Adults average 12.5 cm in total length.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry
• poisonous poisonous

• Sexual Dimorphism
• sexes alike

Development

Nests of Plethodon jordani have never been found. Gravid females move underground in late spring or early summer and oviposit in deep underground recesses. Females oviposit in May and hatching usually occurs in late summer or early autumn, about 2 to 3 months after the eggs were deposited. Newborns remain underground for 10 to 12 months after hatching. Metamorphosis occurs before hatching, so individuals emerge from eggs in small adult form, there is no aquatic larval stage. Small individuals judged to be nearly 1 year old first appear on the surface in May or June. Individuals increase by an average of 12 mm (snouth-vent length) between May and October of their second year.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Courtship begins when a male approaches a female and being to nudge or tap her with his snout. The male then places his mental gland on the female's nasolabial grooves and begins a "foot dance". The foot dance is described as the limbs being raised and lowered off the ground one at a time. The male then moves towards the female's head. The male turns his head under the female's chin and lifts. The male then begins to circle under the female's chin and laterally moves his tail as he circles her. If the female is responsive, she places her chin on his tail and moves forward to the base of his tail. The couple then engages in a tail-straddle walk that may last for an hour. During the walk the male may turn and slap his mental gland on the female's nasolabial region. The male eventually stops moving and begins a series of lateral rocking movements of his sacrum. The female begins with a series of head movements, opposite to the rocking movements of the male. The male then presses his vent to the substratum and releases a spermatophore. Next he flexes his tail to one side and leads the female forward. She stops when her vent is over the spermatophore, then lowers her sacrum and picks up the sperm cap. During this process the male arches the sacral region and does "push-ups" with his hind limbs. The pair usually splits up after the spermatophore is deposited even if the female is unsuccessful at picking it up.

Females may court several times and mate with two or more males in one season. Males will often attempt to mate other males and mimic the behaviors of a female. This is a form of competition in which males cause other males to waste their gametes. In a laboratory study, researchers inhibited females from smelling the male's pheromones, which greatly reduced the response of the female to the courtship ritual. In most cases the female did not respond at all to the male during courtship behavior.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

Male Plethodon jordani mature sexually at approximately 3 years of age. An estimated 25% of females oviposit for the first time 4 years after hatching, another 25% oviposit for the first time 1 year later. The remaining 50% wait until they are 6 years old before they oviposit for the first time. After their first oviposit, females reproduce every other year for the remainder of their lives. Clutch sizes of 3 to 10 have been estimated.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • internal internal
• oviparous oviparous

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female

Lifespan/Longevity

Plethodon jordani has a mean generation time of 9.8 years, with 77% surviving to 10 years old.

Behavior

Plethodon jordani is a solitary species active during moist weather. Plethodon salamanders in general are mostly found in moist areas. Plethodon jordani tends to move to areas where moisture is the greatest within its preferred habitat.

• Key Behaviors
• terricolous
• diurnal diurnal
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

In a study discussed by Petranka (1998), Plethodon salamanders were studied to determine home range and territory size. In the study the maximum distance moved for males was 120.4 meters and 60.6 meters for females. Plethodon jordani is an exceptionally philopatric species of Plethodon and home range sizes may be only a few square meters.

Communication and Perception

The most common form of communication for Plethodon jordani is the use of pheromones. These chemicals play a key role in courtship behaviors and the act of mating.

• Communication Channels
• visual visual
• tactile tactile
• chemical chemical

• Other Communication Modes
• pheromones pheromones
• scent marks scent marks

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

Both male and female salamanders eat the same type and size of prey. On dry nights the majority of individuals will forage on vegetation, whereas, on wet nights, they will roam the forest floor in search of invertebrate prey. Food items in 204 specimens from the Great Smoky Mountains included annelids, snails, millipedes, centipedes, isopods, phalangids, pseudoscorpions, mites, spiders, and a variety of insects. Millipedes are more important during the spring and insect larvae are more important during the fall. Collembolans and annelids tend to increase in importance in higher altitudes. In a study performed by Whitaker and Rubin (1971), the 10 most important prey by volume were: ants, spiders, lepidopteran larvae, beetle larvae, collembolans, millipedes, centipedes, mites, snails, and dipteran larvae.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore
  • eats non-insect arthropods
  • molluscivore molluscivore
  • vermivore
• herbivore herbivore
  • folivore folivore

• Animal Foods
• insects
• mollusks
• terrestrial worms

• Plant Foods
• wood, bark, or stems
• flowers

Predation

Common garter snakes ( Thamnophis sirtalis ) are the largest threats to Plethodon salamanders. The first defense mechanism of Jordan’s salamanders is the bright red cheeks or legs possessed by some individuals. This aposematic coloration is a warning sign to predators. Snake predation upon Plethodon salamanders also elicits other behaviors, including writhing and thrashing movements that coat the predator with slimy secretions, tail autotomy (tail loss), and biting. Bennett and Licht (1974) suggested that the particular antipredator behaviors of amphibian species are correlated with the extent of anaerobiosis during a burst of activity. According to a study by Arnold and Feder (1982), predatory encounters are especially suitable for demonstration of anaerobiosis during spontaneous natural activity, if it does occur. In one trial conducted by Arnold and Feder (1982), a Jordan's salamander escaped the snake by producing thick secretions which actually glued the snake to the substrate (rendering it immobile). Predatory birds are also likely to be important predators of Jordan's salamanders, especially at higher elevations where there are fewer garter snakes.

• Anti-predator Adaptations
• aposematic aposematic

Ecosystem Roles

Hairston et al. (1956) conducted a series of studies on interspecific relationships between P. jordani and P. oconaluftee in the southern Appalachians. In all the studies, the researchers found that the removal of P. jordani caused an increase in P. ocanaluftee . Removal of P. ocanaluftee did not affect P. jordani but did increase the proportion of juveniles in the population. Hairston et al. concluded that competition did exist between the two species but they could not conclude which resource they were competing for.

Economic Importance for Humans: Positive

There is no known benefit provided to humans from Plethodon jordani

Economic Importance for Humans: Negative

There are no known adverse effects of Plethodon jordani on humans.

Conservation Status

Populations of Plethodon jordani and other salamanders are often absent or greatly reduced in number on recent clear-cuts in western North Carolina. Less intensive harvesting practices that leave the basic structure of the forest intact would benefit this and other salamander species in southern Appalachian forests.

Highton (2005) noted significant decline (>40%) across the range of Plethodon . Logging roads, even those no longer in use, have been shown to negatively affect Plethodon abundance.

Other Comments

There are disagreements in the literature with species and subspecies distinctions. According to the latest data, color variation and geographic location are the two main factors in determining the species identification of a particular salamander. There are disagreements in the literature with species and subspecies distinctions.

The Plethodon jordani complex was recently recognized by Highton and Peabody (2000), which contains 7 species ( P. jordani , P. metcalfi , P. shermani , P. cheoah , P. amplus , P. meridianus , and P. montanus ). The splitting of P. jordani appears to be gaining acceptance.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Andrea Helton (author), Radford University, Karen Powers (editor, instructor), Radford University.

References

Adams, D. 2004. Character Displacement via Aggressive Interference in Appalachain Salamanders. Ecology , 85/10: "2664-2670".

Arnold, S., M. Feder. 1982. Anaerobic Metabolism and Behavior During Predatory Encounters Between Snakes ( Thamnophis elegans ) and Salamanders ( Plethodon jordani ). Oecologia , 53: 93-97.

Center for North American Herpetology, 2008. "The Center for North American Herpetology web portal" (On-line). Accessed January 21, 2008 at http://www.cnah.org/index.asp .

Conant, R., J. Collins. 1998. A field guide to reptiles & amphibians : eastern and central North America . Boston: Houghton Mifflin.

Dunn, E. 1926. The Salamanders of the Family Plethodontidae . Northampton, Mass.: Smith College.

Goin, C., O. Goin. 1962. Introduction to Herpetology . USA: W.H. Freeman and Company.

Hairston, N. 1956. Interspecies competition and its probable influence upon the vertical distribution among Appalachian salamanders of the genus plethodon.. Ecology , 32: 266-275.

Highton, R. 2005. Declines of eastern North American Woodland Salamanders (Plethodon). Pp. 34-46 in Amphibian Declines . Berkeley, California: University of California Press.

Houck, L., A. Bell, N. Reagan-Wallin, R. Feldhoff. 1998. Effects of Experimental Delivery of Male Courtshop Pheromones on the Timing of Courtship in a Terrestrial Salamander, Plethodon jordani. Copeia , 1: "214-219.

Martof, B., W. Palmer, J. Bailey, J. Harrison. 1980. Amphibians and Reptiles of the Carolina and Virginia . North Carolina: The University of North Carolina Press.

Mitchell, J., K. Reay. 1999. Atlas of Amphibians and Reptiles in Virginia . Richmond: Virginia Department of Game and Inland Fisheries.

Petranka, J. 1998. Salamanders of the United States and Canada . Washington: Smithsonian Institution Press.

Rittenhouse, T., R. Semlitsch. 2006. Grasslands as movement barriers for a forest-associated salamander: migration behavior of adult and juvenile salamanders at a distinct habitat edge. Biological Conservation , 131: 14-22.

Stupka, A., J. Huheey. 1967. Amphibians and Reptiles of the Great Smoky Mountains Nation Park . Knoxville, TN: University of Tennessee Press.