Gyrinophilus palleucus McCrady, 1954
Tennessee Cave Salamander, Big Mouth Cave Salamander, Pale Salamander
© 2010 Matthew Niemiller (1 of 33)
This species is mostly neotenic, but naturally metamorphosed individuals are occasionally found (Yeatman and Miller 1985, Sinking Cove Cave; Brandon et al. 1986, Custard Hollow Cave). It can be induced to metamorphose in a laboratory setting; Dent and Kirby-Smith (1963) reported that two untreated individuals metamorphosed completely and one metamorphosed partially, while Blair (1961) reported that one individual metamorphosed after three months of iodine-potassium iodide treatment but another did not metamorphose after six months of treatment, and Yeatman (1967) was also able to hormonally induce metamorphosis in this species.
Gyrinophilus palleucus has 2 subspecies, G. p. necturoides and G. p. palleucus. Subspecies differ slightly in body pigmentation, head width, leg length, eye size, and modal number of trunk vertebrae (Brandon 1966; Brandon 1967).
The Big Mouth Salamander, G. p. necturoides, differs from G. p. palleucus by having one or two additional costal grooves (usually 18 costal grooves, sometimes 19 in G. p. necturoides; usually 17 costal grooves, sometimes 18 in G. p. palleucus) and by its darker, spotted coloration. G. p. necturoides ranges in color from a russet brown to dark brown to deep purple-brown on the dorsum, with numerous blackish spots that extend from the level of the jaw down to the anterior third of the tail. A dark chevron-like pattern is sometimes present. The venter is pearl-gray, with rosy coloration at the limb insertions and the vent. Two parallel lateral rows of small white dots, corresponding to the costal spaces, run along the sides from the axilla onto the basal half of the tail. A distinct, pale cheek stripe extends from the base of the most ventral gill ramus onto the side of the head. Gills are a deep brilliant red and extend back to the fourth costal groove. Between adpressed limbs, 7-8 costal grooves are visible (Lazell and Brandon 1962).
The Pale Salamander, G. p. palleucus, is the paler of the 2 subspecies and generally has fewer costal grooves (17 costal grooves, sometimes 18 in G. p. palleucus, vs. 18 costal grooves, sometimes 19 in G. p. necturoides; Lazell and Brandon 1962).
Distribution and Habitat
Country distribution from AmphibiaWeb's database: United States
U.S. state distribution from AmphibiaWeb's database: Georgia, Tennessee
Adults have been found in caves with streams, rimstone pools, stream runs and pools, and pools isolated by receding water. Substrates can be rock, gravel, sand, or mud. Water is usually clear and free of sediment. Sinkholes are an important habitat component because they allow detritus inflow, which sustains large invertebrate populations (Caldwell and Copeland 1992). McCrady (1954) found individuals in Tennessee caves at altitudes 900-1200 ft above sea level.
Life History, Abundance, Activity, and Special Behaviors
The breeding season is not known, but Lazell and Brandon (1962) reported that H. C. Yeatman found an adult male with a spermatophore protruding from its cloaca on August 24, 1954. Simmons (1975) suggested that females have irregular breeding patterns and may skip one or more years between breeding. He also suggested that females oviposit in autumn or early winter, based on discovery of small hatchlings on December 21 and February 15. Eggs have never been found and its nesting biology is unknown (Petranka 1998). Growth rates are probably slow and larvae may take many years to become sexually mature (Brandon 1967). All specimens of G. p. palleucus greater than 70 mm SVL are sexually mature (Petranka 1998).
Stomach contents of 19 specimens from several caves included oligochaetes, amphipods, isopods, crayfish, cladocerans, beetles, stoneflies, mayflies, dipterans, caddisflies, thrips, and two conspecific salamanders (Simmons 1975). Amphipods made up 21% of the prey items (Simmons 1975). Miller and Niemiller (2008) reported that isopods were a common prey item, and that occasionally salamanders being handled would regurgitate epigean (relatively surface-dwelling) invertebrate prey such as earthworms and coleopteran larvae.
Few predators have been documented. Simmons (1975) reported cannibalism. Lazell and Brandon (1962) reported that captive G. p. necturoides consumed adult Eurycea bislineata as well as earthworms and suggested that the urodele skull base and vertebrae found in the stomach of one wild-caught specimen were probably from a conspecific G. p. necturoides. Lee (1969) found a large adult in the stomach of a cave-dwelling bullfrog. Crayfish probably feed on small larvae (Petranka 1998).
Trends and Threats
Local populations are assumed to be very small since surveys rarely find more than 10-20 individuals per cave visit (Petranka 1998). However, Miller and Niemiller (2008) suggest that more animals may reside in subterranean waters that connect caves to each other and in caves inaccessible to humans.
It is found in at least one protected area: Russell Cave National Monument, Tennessee (Godwin 1995).
Although Beachy (2005) suggested that all populations of Tennessee Cave Salamanders were declining, based on comparisons of historic and recent survey numbers, and Caldwell and Copeland (1992) suggested that some populations, such as the population in Custard Hollow Cave, Franklin Co., TN, may be declining, Miller and Niemiller (2008) reported stable or increasing populations.
Specifically, Miller and Niemiller (2008) found that Crow Creek drainage-associated caves in Franklin Co., TN (Custard Hollow Cave, Cave Cove Cave, and Sinking Hole Cave), plus Mudflats Cave, appeared to have stable, robust populations with no declines. Furthermore, the Big Mouth Cave population appeared to be increasing (Miller and Niemiller 2008). In contrast, the Central Basin, Warren Co., Marion Co., northwest Georgia, nearly all Valley and Ridge caves, and several Grundy Co. caves were found to have very low abundance of salamanders (Miller and Niemiller 2008).
Agricultural and residential runoff, increased runoff and silt load due to deforestation, mining, urbanization, flooding after dam construction, and deposition of trash in sinkholes may all be contributing to declines (Petranka 1998, Stuart et al. 2008). Overcollecting may also be contributing to population decline of this species (Miller and Niemiller 2008).
Possible reasons for amphibian decline
Habitat modification from deforestation, or logging related activities
Blair, A. F. (1961). ''Metamorphosis of Pseudotriton palleucus with iodine.'' Copeia, 1961, 499.
Brandon, R.A. (1965). ''A new race of neotenic salamander Gyrinophilus palleucus.'' Copeia, 1965(3), 346-352.
Brandon, R.A. (1966). ''Systematics of the salamander genus Gyrinophilus.'' Illinois Biological Monographs 35:1-86.
Brandon, R.A. (1967). ''Gyrinophilus palleucus.'' Catalogue of American Amphibians and Reptiles.
Brandon, R.A., Jacobs, J., Wynn, A. and Sever, D.M. (1986). ''A naturally metamorphosed Tennessee cave salamander (Gyrinophilus palleucus).'' Journal of the Tennessee Academy of Science, 61, 1-2.
Caldwell, R.S. and Copeland, J.E. (1992). ''Status and habitat of the Tennessee cave salamander, Gyrinophilus palleucus.'' Final report submitted to Tennessee Wildlife Resources Agency, Nashville, Tennessee.
Dent, J.N and Kirby-Smith, J.S. (1963). ''Physiology and morphology of the cave salamander Gyrinophilus palleucus.'' Copeia, 1963(1), 119-130.
Godwin, J.C. (1995). ''Reassessment of the historical localities of the Tennessee cave salamander (Gyrinophilus palleucus) in Alabama.'' Unpublished report submitted to Alabama Natural Heritage Program.
Lazell, J. D., and Brandon, R. A. (1962). ''A new stygian salamander from the Southern Cumberland Plateau.'' Copeia, 1962(2), 300-306.
Lee, D. S. (1969). ''Notes on the feeding behavior of cave-dwelling bullfrogs.'' Herpetologica, 25, 211-212.
McCrady, E. (1954). ''A new species of Gyrinophilus (Plethodontidae) from Tennessee caves.'' Copeia, July 29(3), 200-206.
Miller, B.T. and Niemiller, M. L. (2008). ''Distribution and relative abundance of Tennessee cave salamanders (Gyrinophilus palleucus and Gyrinophilus gulolineatus) with an emphasis on Tennessee populations.'' Herpetological Conservation and Biology, 3(1), 1-20.
Petranka, J. W. (1998). Salamanders of the United States and Canada. Smithsonian Institution Press, Washington D.C. and London.
Simmons, D. (1975). ''The evolutionary ecology of Gyrinophilus palleucus.'' Unpublished master's thesis, University of Florida, Gainesville, Florida.
Simmons, D. (1976). ''A naturally metamorphosed Gyrinophilus palleucus (Amphibia, Urodela, Plethodontidae).'' Journal of Herpetology, 10(3), 255-257.
Stuart, S., Hoffmann, M., Chanson, J., Cox, N., Berridge, R., Ramani, P., Young, B. (eds) (2008). Threatened Amphibians of the World. Lynx Edicions, IUCN, and Conservation International, Barcelona, Spain; Gland, Switzerland; and Arlington, Virginia, USA.
Yeatman, H. C. (1967). ''Artificially metamorphosed neotenic cave salamanders.'' Journal of the Tennessee Academy of Science, 52, 16-22.
Yeatman, H. C., and Miller, H. B. (1985). ''A naturally metamorphosed Gyrinophilus palleucus from the type-locality.'' Journal of Herpetology, 19, 304-306.
Originally submitted by: Anna Chow (first posted 2010-02-04)
Edited by: Kellie Whittaker (2010-03-08)
Species Account Citation: AmphibiaWeb 2010 Gyrinophilus palleucus: Tennessee Cave Salamander <https://amphibiaweb.org/species/4064> University of California, Berkeley, CA, USA. Accessed Mar 22, 2023.
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Citation: AmphibiaWeb. 2023. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 22 Mar 2023.
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