Wednesday, January 23, 2013

Video: Valentine's Cave Dipluran (Litocampa valentinei)

This is my first attempt at publishing a video of subterranean life on my YouTube channel. The video was shot using an Olympus TG-1iHS 12 MP Waterproof Digital Camera under low-light conditions. The quality isn't great but it is not terrible either. I will work toward producing higher quality videos in the future.

The video features a cave dipluran crawling along a rock boulder in the dark zone of Hering Cave, Madison Co., Alabama. Diplurans are primitive wingless relatives of insects belonging to the class Hexapoda. They have three pairs of walking legs along with two long antennae extending from the head and two long cerci extending from the posterior end of the abdomen. Diplurans use their antennae and cerci in concert to sense their environment. In addition to lacking wings,  diplurans also lack eyes.

Diplurans are common in caves throughout the Interior Plateau, Appalachians and Ozark Highlands of eastern North America where they are most often observed on damp substrates near a water source, such as along mud banks of cave streams. The species in the video is Valentine's Cave Dipluran (Litocampa valentinei), which occurs in caves of northeastern Alabama and south-central Tennessee along the Cumberland Plateau.

Tuesday, January 22, 2013

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.

Thursday, January 3, 2013

Book Review: Cave Life of the Virginias

The Biology Section of the National Speleological Society recently published Cave Life of the Virginias: A Field Guide to Commonly Encountered Species in June 2012 written by Drs. Daniel W. Fong, Megan L. Porter, and Michael E. Slay. To my knowledge, this work represents the first field guide on subterranean life of eastern North America that can actually be taken underground and can hold up to the wear and tear of caving. The 42 spiral-bound pages are laminated and the book is perfectly sized to fit into a cave pack.

Cave Life of the Virginias highlights species that are commonly observed in Appalachian caves of Virginia and West Virginia to help cavers identify these unique animals. The beginning of the book briefly discusses caves as important habitats for many species, cave zones inhabited by wildlife, and the ecological classification of cave organisms. The twenty species accounts are organized into three groups based on where particular are most frequently encountered: the entrance zone, transition zone, and dark zone. Each species or species complex (e.g., cave millipedes) is illustrated with a photograph and often with a silhouette image (for species that are small) representing the actual size of the organism. For species or species complexes that occur in the dark zone, distribution maps are provided. Species accounts provide detailed information on the appearance, coloration, and other distinguishing features to assist in identification. Additional information on natural history and conservation is also provided. The final five pages of the book are devoted to avenues to seek additional information about the species highlighted, including books, journal articles, and websites.

Cave Life of the Virginias is written for a general audience with some knowledge of biology (i.e., the average caver). Perhaps its best feature are the high quality photographs taken by several cave biologists that begin each species account, including some species that are quite small (<5 mm). While this book won't allow you to identify most cave organisms to species (which often requires dissection for many groups), Cave Life of the Virginias can be used to quickly determine a springtail from a dipluran or an isopod from an amphipod.

I highly recommend that anyone with even a slight interest in caving and cave life purchase Cave Life of the Virginias. The book is very affordable at $16 US and can be purchased from the NSS Bookstore or from Speleobooks. Proceeds generated from sales are used toward the publication of additional field guides in the series.

Funding for Cave Life of the Virginias was provided by the Cave Conservancy of the Virginias (administered by Karst Waters Institute). Cave Life of the Virginias is the first of a series of cave life field guides of the United States. Future titles will highlight subterranean biodiversity of TAG and the Ozarks.