FWGNA > Species Accounts > Hydrobiidae > Holsingeria unthanksensis
Holsingeria unthanksensis Hershler 1989

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> Habitat & Distribution

This stygobiotic hydrobiid has been documented from perhaps 4 - 5 caves and springs in Lee County, Virginia (draining west toward Tennessee), according to the VA Natural Heritage Click for largerProgram database.  Holsingeria also apparently ranges through subterranean waters at least 500 km north, up into Skyline Caverns and the drainage of the Shenandoah (Hershler et al. 2003).  In Unthanks Cave, the rather small and localized population of Holsingeria inhabits rocks and cobbles in a series of clear pools.  FWGNA incidence rank I-1.

A general review of the zoogeography of North American cavesnails has been offered by Hershler & Holsinger (1990).

> Ecology & Life History

Hydrobiids seem to be rather nonspecific grazers of small particles (Dillon 2000: 94-97).  One might reasonably hypothesize that populations of the blind, unpigmented H. unthanksensis are supported by organic particles raining down from cave ceilings above.   I am not aware of any formal study on the life history of Holsingeria populations, although one might hypothesize that the unusually stable environments they enjoy could promote continuous reproduction.  Hydrobiids are in general dioecious, the males being characterized by a penis arising from the neck.   Eggs are generally laid singly, attached in spare capsules to solid substrates.

> Taxonomy & Systematics

The original description of Hershler (1989) included observations regarding the anatomy and morphology of this unusual taxon of hydrobiid snails. Holsingeria belongs to the hydobiid subfamily Lithoglyphinae, characterized by a simple penis (Kabat & Hershler 1993).  The taxon made a cameo appearance among the outgroups in a molecular phylogeny of the nymphophiline hydrobiids published by Hershler and colleagues (2003).

> Supplementary Resources


>Essays

  • See my post to the FWGNA blog of 22Aug07 entitled Cave Snail Adventure for field observations and additional photos of H. unthanksensis.

> References

Dillon, R.T., Jr. (2000) The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, United Kingdom.
Hershler, R. H. (1989) Holsingeria unthanksensis, a new genus and species of aquatic cavesnail from eastern North America. Malac. Rev. 21: 93-100.
Hershler, R. H. & J. R. Holsinger (1990)  Zoogeography of North American hydrobiid cavesnails.  Stygologia 5: 5-16. 
Hershler, R. H., H-P. Liu & F. G. Thompson (2003)  Phylogenetic relationships of North American nymphophiline gastropods based on mitochondrial DNA sequences.  Zoologica Scripta 32: 357-366.
Kabat, A.R., and R. Hershler (1993) The prosobranch snail family Hydrobiidae (Gastropoda: Rissooidea): review of classification and supraspecific taxa. Smithsonian Contributions to Zoology 547:1-94. 
Stewart, T. W., & R. T. Dillon, Jr.  (2004)  Species composition and geographic distribution of Virginia's freshwater gastropod fauna: A review using historical records.  Am. Malac. Bull. 19: 79-91.