Species Profile: Appalachian Cave Harvestman (Tolus appalachius)

Adult from Grundy Co., TN (Photo by Dante Fenolio)

Appalachian Cave Harvestman
Tolus appalachius
Goodnight and Goodnight, 1942

Conservation status: IUCN Red List - Not Assessed; NatureServe - G3G4 (Alabama: SNR; Tennessee: S3). This species is tracked by the state of Tennessee.

Description: Tolus appalachius is one of three described species of troglobiotic harvestmen in the Interior Plateau. Harvestmen are arachnid cousins of spiders but they lack silk organs and venom glands in their chelicerae (mouthparts). In addition, the cephalothorax and abdomen are fused in harvestmen but are distinct in spiders. Tolus appalachius is a small cave-dwelling relative of the "daddy longlegs" you might find in your basement or shed. It lacks eyes, is depigmented and has exceptionally long legs relative to the size of the body. The body is oval in shape and 2-4 mm long in adults, with legs up to 20 mm in length. The legs and chelicerae appear white in color, while the body is often a light creamy orange-white. The body of younger instars appears completely white.

Distribution: This harvestman occurs in caves primarily along the Western Escarpment of the Cumberland Plateau from southern Fentress and Overton counties, Tennessee, south-southwestward into Jackson County, Alabama. Tolus has been reported from about 20 caves but likely occurs in many other cave systems.

Habitat: Tolus is primarily reported from the dark zone of caves where it often found in moist microhabitats, such as on or underneath decaying wood, rocks along the stream margins or within crevices in cave walls, particularly near the junction of mud banks and solid rock. It is seldom found in drier cave passages.

Adult from Grundy Co., TN (Photo by Matthew L. Niemiller)

Natural History: Very little is known about the natural history of cave-dwelling harvestmen, including T. appalachius. Presumably, this species has an omnivorous diet like other harvestmen, feeding on smaller invertebrates and scavenging on fungi, decaying vegetation and animal matter. Nothing is known regarding reproduction in this species. Small instars have been found throughout the year, suggesting that reproduction may be not be seasonal. Like other harvestmen, Tolus clean their legs after feeding by running each leg through their chelicerae. When disturbed, Tolus will often play dead tucking their long legs into their body. Unlike several species of surface-dwelling harvestmen, cave-dwelling T. appalachius are not known to aggregate in large numbers of individuals.

Conservation: Most populations are reportedly small based on collection data. I have seen as many as 18 individuals during a cave bioinventory. This species is assigned a global NatureServe conservation rank of 'Vulnerable' to 'Apparently Secure' (G3G4), but it has not yet been assessed under IUCN Red List criteria. Like other cave terrestrial invertebrates, Tolus populations may be threatened by habitat degradation, pollution, flooding associated with impoundments and significant human visitation. No species-specific management or conservation plans are being conducted at this time. Entrances to almost all known cave localities are owned by private landowners.

Notes: A population in Overton County, Tennessee, may be distinct and warrant recognition as a new species. Hedin and Thomas (2010) recently investigated convergent morphological evolution in cave harvestmen, including Tolus appalachius.

Select References

Goodnight CJ, Goodnight ML. 1942. New Phalangodidae (Phalangida) from the United States. American Museum Novitates 1188: 1-18.

Goodnight CJ, Goodnight ML. 1960. Speciation among cave opilionids of the United States. American Midland Naturalist 64: 34-38.

Hedin M, Thomas SM. 2010. Molecular systematics of eastern North American Phalangodidae (Arachnida: Opiliones: Laniatores), demonstrating convergent morphological evolution in caves. Molecular Phylogenetics and Evolution 54: 107-121.

Lewis JJ. 2005. Bioinventory of caves of the Cumberland Escarpment Area of Tennessee. Final Report to Tennessee Wildlife Resources Agency & The Nature Conservancy of Tennessee. Lewis & Associates LLC, 158 pp.

Niemiller ML, Zigler KS, Fenolio DB. 2013. Cave life of TAG: A guide to commonly encountered species in Tennessee, Alabama and Georgia. Biology Section of the National Speleological Society, Huntsville, Alabama. 46 pp.

Species Profile: East Tennessee Cave Beetle (Pseudanophthalmus tennesseensis)

Pseudanophthalmus tennesseensis, Roane County, TN. (Photo by Michael E. Slay)

East Tennessee Cave Beetle
Pseudanophthalmus tennesseensis

Conservation status: IUCN Red List - Not Assessed; NatureServe - G3 (Tennessee: S2). This species is tracked by the state of Tennessee.

Description: Pseudanophthalmus tennesseensis is a small, eyeless and depigmented ground beetle red to reddish-brown in coloration. Adults are only 4 mm in length and lack wings. They have prominent, long legs and thread-like antennae. Like most Pseudanophthalmus, this species is pubescent, possessing three well-defined pairs of discal setae (chitinous hairs) on the elytra, a character used to separate the genus from other co-occurring genera of cave carabid beetles. Species identification is difficult in this genus and requires the dissection and microscopic examination of male genitalia. This species is the type species of the P. tennesseensis species group found in east Tennessee.

Distribution: Pseudanophthalmus tennesseensis is known from only four cave systems in the Ridge and Valley of east Tennessee: three caves in Knox County and one cave in Roane County. All of these cave systems lie south of the Copper Creek Fault in Knox and Roane counties. A potential new population was discovered in Knox County in the Keller Bend area of the Tennessee River to the southeast of all known localities, but taxonomic identification has not yet been confirmed.

Habitat: Most specimens of P. tennesseensis have been collected primarily under rocks or rotting wood found on damp silt away from streams. However, the lone specimen found in the potential new locality in Knox County, Tennessee, was found near a rimstone pool. 

Natural History: Little information is available regarding the life history and ecology of P. tennesseensis. Larvae have not been reported. Based on information from studies of other Pseudanophthlamus species, eggs of this species are probably laid in autumn with larvae appearing in winter. Larvae then pupate in late winter into early spring with tenerals (soft-bodied adults shortly after emerging from pupae or from molting) appearing the following summer in June and July. By the following autumn, beetles are almost fully sclerotized. Pseudanophthalmus beetles are predatory and are often actively observed walking along cave mud and sediments along streams and other sources of water. The diet of P. tennesseensis has not been studied but likely includes enchytraid and tubificid worms found in association with cave mud and sediments. Predators are unknown. This species is not known to co-occur with any other cave carabid beetles. Data on population size is unavailable. Valentine (1937) collected a male and female on separate trips from the type locality, Cherokee Caverns (TKN22) in Knox County, while Barr (1965) collected five topotypes from the same cave in 1958. Barr (1965) also reported that the species was "comparatively abundant" from a cave in Roane County, Tennessee. A recent bioinventory of this cave found only two P. tennesseensis in May 2013.

Conservation: Pseudanophthalmus tennesseensis is known from just four localities in a relatively small geographic area. Most populations are reportedly small in size based on collection information. Accordingly, the species is assigned a global NatureServe conservation rank of 'Vulnerable' (G2) but has not yet been assessed under IUCN Red List criteria. Cave beetle populations may be threatened by habitat degradation, pollution, flooding associated with impoundments, and human visitation. At least two localities currently or have received considerable human visitation. With increased human presence in caves comes increased risk to beetle populations because of vandalism, littering, disruption of cave microhabitats, and potential trampling. However, no data exist linking any of these threats with possible population declines. No species-specific management or conservation plans are being conducted for P. tennesseensis at this time. Entrances to all known cave localities are owned by private landowners. The type locality was formerly a small, commercial cave but operations have since ceased. A potential new locality was discovered during a biological inventory of caves in Knox County in May 2013.

Select References

Barr TC. 1965. The Pseudanophthalmus of the Appalachian Valley (Coleoptera: Carabidae). American Midland Naturalist 73: 41-72.

Barr TC. 1981. Pseudanophthalmus from Appalachian caves (Coleoptera: Carabidae): the engelardti complex. Brimleyana 5: 37-94.

Barr TC. 2004. A classification and checklist of the genus Pseudanophthalmus Jeannel (Coleoptera: Carbidae: Trechinae). Virginia Museum of Natural History Special Publication 11. 52 pp.

Valentine JM. 1937. Anophthalmid beetles (fam. Carabidae) from Tennessee caves. Journal of the Elisha Mitchell Science Society 53: 93-100.

Species Profile: Tennessee Cave Salamander (Gyrinophilus palleucus)

Adult, Jackson Co., Alabama (Photo by Dante Fenolio)

Tennessee Cave Salamander
Gyrinophilus palleucus
 
Conservation Status: IUCN Red List - Vulnerable B2ab(iii,iv); NatureServe - GSG3 (Alabama: S2, Georgia: S1, Tennessee: S2). This species is 'Protected' in Alabama, 'Threatened' in Georgia, and 'Threatened' in Tennessee.

Description: Gyrinophilus palleucus is one of the four species of cave-obligate salamanders found east of the Mississippi River in the United States. They are large, aquatic salamanders that can reach lengths of 210 mm. Unlike most species of salamanders, Gyrinophilus palleucus does not readily undergo metamorphosis and attains sexual maturity in the larval stage. Consequently, they retain the conspicuous paired gills located on each side of the back of the head throughout life. Adults have a broad head with a flattened, shovel-like snout. They eyes are reduced in size compared to related surface-dwelling cousins like the Spring Salamander (G. porphyriticus) and Red Salamander (Pseudotriton ruber), but they are not completely degenerate as observed in other obligate cave-dwelling salamanders. However, some adults may have skin that completely covers their eyes. Also unlike other cave salamanders, G. palleucus is distinctly pigmented and ranges in color from pale pink and lacking spotting to dark reddish purple or brown with distinct spots or blotches on the back. Adults also have a series of unpigmented dots that represent pores of the lateral line system on the head and along the sides of the body that are used to detect moving prey, conspecifics and potential predators in their aquatic environment. Juveniles generally resemble adults but are much paler, lack conspicuous spots or blotches, and possess eyes that are proportionally larger relative to head size. Two subspecies are recognized: the Pale Salamander (G. p. palleucus) and the Big Mouth Cave Salamander (G. p. necturoides). These subspecies differ in coloration, relative eye size and number of trunk vertebrae but are thought to hybridize throughout much of northern Alabama.

Juvenile, Jackson Co., Alabama

Distribution: Gyrinophilus palleucus has been reported from 80 localities in northern Alabama (39 caves), northwestern Georgia (2 caves) and central Tennessee (38 caves and 1 spring). Its distribution includes caves in the Inner Nashville Basin, Eastern Highland Rim and escarpments of the Cumberland Plateau.

Habitat: Both adults and juveniles are most often observed resting on the bottom of shallow pools in the dark zone of subterranean streams but are also can be found in riffles and rimstone pools. They are most often found underneath rocks or within mats of organic debris washed into caves. Gyrinophilus palleucus has been found within the twilight zone of caves on occasion and at least one report was from a surface spring after heavy rainfall.

Adult, Coffee Co., Tennessee (Photo by Matthew L. Niemiller)

Natural History: Little is known about the life history and ecology of G. palleucus. This is particularly true for aspects of reproductive biology. Eggs have never been found, although it is presumed that mating and egg-laying occurs from autumn to early winter. Although data are limited, it appears that G. palleucus is long-lived and may take 5-8 years to reach sexual maturity. Tennessee Cave Salamanders are one of the top predators in the cave systems they inhabit. They will eat almost anything that will fit into their mouths, including isopods, amphipods, worms, small crayfish, and even smaller conspecifics. Metamorphosis is rare in the wild, but G. palleucus can be induced to metamorphose in the lab.

Adult, Warren Co., Tennessee (Photo by Matthew L. Niemiller)

Conservation: Populations of G. palleucus face a number of threats, such as habitat degradation, groundwater pollution, and alteration of water flow and organic input into cave systems associated with urbanization, mining, silviculture, agriculture, and the construction of dams. However, it is unclear what negative impacts these threats have had on populations of G. palleucus. Several populations studied appear to be stable and are under no immediate threat of extirpation. Moreover, recent surveys have revealed that the species is more widespread and abundant than previously believed. The entrances to several cave systems inhabited by G. palleucus are owned or managed by state or federal agencies or cave conservation organizations, which affords some protection.
 
Fun Fact: The Tennessee Cave Salamander is officially recognized as the state amphibian of Tennessee.

Select References

Beachy CK. 2005. Gyrinophilus palleucus. Pp. 775-776 in Lannoo M (ed.). Amphibian Declines: The Conservation Status of United States Species. University of California Press, Berkeley.

Brandon RA. 1966. Systematics of the salamander genus Gyrinophilus. Illinois Biological Monograph 35: 1-85.

Brandon RA. 1967. Food and intestinal parasite of the troglobitic salamander Gyrinophilus palleucus necturoides. Herpetologica 23: 52-53.

Brandon RA. 1971. North American troglobitic salamanders: some aspects of modification in cave habitats, with special reference to Gyrinophilus palleucus. Bulletin of the National Speleological Society 33: 1-21.

Godwin JC. 2008. Tennessee cave salamander. Gyrinophilus palleucus. Pp. 202-204 in Jensen JB, Camp CD, Gibbons W, Elliott MJ (eds.). Amphibians and Reptiles of Georgia. University of Georgia Press, Athens.

Goricki S, Niemiller ML, Fenolio DB. 2012. Salamanders. Pp. 665-676 in White WH, Culver DC (eds.). Encyclopedia of Caves. 2nd edition. Elsevier.

Huntsman BM, Venarsky MP, Benstead JP, Huryn AD. 2011. Effects of organic matter availability on the life history and production of a top vertebrate predator (Plethodontidae: Gyrinophilus palleucus) in two cave streams. Freshwater Biology 56: 1746-1760.

Lazell JD, Brandon RA. 1962. A new stygian salamander from the southern Cumberland Plateau. Copeia 1962: 300-306.

McCrady E. 1954. A new species of Gyrinophilus (Plethodontidae) from Tennessee caves. Copeia 1954: 200-206.

Miller BT, Niemiller ML. 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: 1-20.

Miller BT, Niemiller ML. 2011. Tennessee cave salamander. Gyrinophilus palleucus. Pp. 175-178 in Niemiller ML, Reynolds RG (eds). The Amphibians of Tennessee. University of Tennessee Press, Knoxville.

Mount RH. 1975. The Reptiles and Amphibians of Alabama. University of Alabama Press, Tuscaloosa.

Niemiller ML, Fitzpatrick BM, Miller BT. 2008. Recent divergence with gene flow in Tennessee cave salamanders (Plethodontidae: Gyrinophilus) inferred from gene genealogies. Molecular Ecology 17: 2258-2275.

Niemiller ML, Miller BT, Fitzpatrick BM. 2009. Systematics and evolutionary history of subterranean salamanders of the genus Gyrinophilus. Proceedings of the International Congress of Speleology, Kerrville, Texas 15: 242-248.

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

Yeatman HC, Miller HB. 1985. A naturally  metamorphosed Gyrinophilus palleucus from the type-locality. Journal of Herpetology 19: 304-306.