Plethodon richmondiSouthern Ravine Salamander

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Geographic Range

This salamander ranges from western Pennsylvania to Indiana. It occurs in the Lake Erie basin also (Harding, 1997). There are no conspicuous patterns of geographic variation in coloring or patterning, instead regional populations are distinguished by the number of costal grooves (Petranka, 1998).

Habitat

The ravine salamander gets its name from inhabiting the slopes of woodland ravines and valleys, it is usually found under a flat rock. In the hottest parts of the summer they move into the ground, a depth of over a meter (3.3ft.) has been reported (Harding, 1997). Little evidence has been found to indicate that this salamander is territorial, it is in fact less aggressive than other Plethodon species (Petranka, 1998).

Physical Description

This species is very long and slender with short legs, it has been described as a "worm with legs," (Conant and Collins 1998). The tail of adults makes up about 50% of the total body length. The dorsal coloration is seal brown to nearly black but sprinkled with silvery-white and bronze speckles. The sides have very small irregular white blotches and 20-33 costal grooves (Petranka, 1998). The belly is dark gray with lighter gray speckles, leading to an even more heavily mottled chin. The adult length runs from 7.5 to 14.4 cm. (3 to 5.6 in.) Males are slightly larger than the females with a conspicuous mental gland on the chin (Harding, 1997).

Development

Reproduction

The mating season for this salamander extends from autumn through early spring. Most females oviposit in deep underground passageways, and are likely to brood their eggs through hatching. Hatching occurs in late summer or early fall; however most hatchlings do not move to ground surface until the following spring. Hatchlings are light grey above with an immaculate belly, and reach an average length of 14-15mm. SVL. Females reproduce biennially. Male salamanders reach sexual maturity slightly more than 2 years after hatching while females begin maturing when 2 years old (Petranka, 1998).

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)

Behavior

When uncovered in a field, individuals may assume a coiled, motionless position, hoping to be less inconspicuous to predators. Individuals also have been known to avoid substrates marked with the scent of a major predator: the ringneck snake (Diadophis punctatus). Courtship of the ravine salamander includes the tail-straddle walk like other Plethodontids. Body snapping and pulling are employed by males to abrade the skin of females to introduce mental gland secretions into the circulatory system (Petranka, 1998).

Food Habits

The Ravine salamander has a diet that consists mainly of small insects such as ants and beetles. They will also eat pill bugs, earthworms, spiders, and snails (Harding, 1997).

Economic Importance for Humans: Positive

With their affinity to habitats with steep gradients, Ravine salamanders seem to be more specialized than other Great Lakes plethodon. They are important members to the woodland floor community (Harding, 1997).

Conservation Status

Deforestation and urbanization are the primary factors that have eliminated the local populations of this species throughout its range (Petranka, 1998).

Contributors

Angie Hastings (author), Michigan State University, James Harding (editor), Michigan State University.

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.

ectothermic

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

forest

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

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.

motile

having the capacity to move from one place to another.

native range

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

References

Conant, R., J. Collins. 1998. Reptiles and Amphibians: Peterson Field Guides 3rd. ed.. New York: Houghton Mifflin Company.

Harding, J. 1997. Amphibians and Reptiles of the Great Lakes Regions. Michigan: University of Michigan Press.

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