> Fontigens nickliniana (Lea 1838)
  
> Habitat & Distribution
This little hydrobiid ranges from Wisconsin through Indiana, Illinois, and Michigan to western New York and south through Virginia (Jokinen 1992, Hershler et al. 1990), with one extralimital population in central Alabama.  Like all members of the genus Fontigens, F. nickliniana is restricted to springs, spring runs, and streams and pools inside caves.  In Virginia, populations of F. nickliniana are typically found on stones, water cress, and other aquatic vegetation in cool, flowing water at or near spring heads.

> Ecology & Life history
I am not aware of any good study on the life history of Fontigens.  But populations typically seem to maintain high densities year round, as though reproduction might be continuous.  Fontigens nickliniana seems largely restricted to limestone springs, suggesting a requirement for high calcium concentration or some other correlate of water hardness. 

> Taxonomy & Systematics
This is the most widespread and common of the nine Fontigens species monographed by Hershler et al. (1990).  Its taxonomy is stable. 

>Essay
A photo comparing living F. nickliniana to Fontigens orolibas is available from my 26July06 essay entitled "Springsnails of the Blue Ridge." 

 
>References
Hershler, R., J.R. Holsinger & L. Hubricht (1990) A revision of the North American freshwater snail genus Fontigens (Prosobranchia: Hydrobiidae). Smithsonian Contributions to Zoology 509:1-49,  Jokinen, E.H. (1992) The freshwater snails of New York State. New York State Museum Biological Survey, New York State Museum Bulletin 482.  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.