> Habitat & Distribution

Fontigens nickliniana 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.  In our study area populations are restricted to the Ridge and Valley Province, especially in rich, cold, hardwater springs associated with lush beds of water cress.  Our northernmost records are in central Pennsylvania, and our southernmost are in spring-run tributaries of the New River in southern Virginia, draining west into The Ohio.

Like all members of the genus, F. nickliniana populations reach maximum abundance on solid substrates in springs, spring runs, and caves.  Population densities become rapidly attenuated downstream, as though dependent on constant temperature or some other unique aspect of the spring environment.  FWGNA incidence rank I-4.

> Ecology & Life History

Fontigens nickliniana has often been called the "water cress snail" (Berry 1943).  They do not seem to damage the tissues of the cress itself, but rather graze on the epiphytic diatoms and detritus.  We are 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.  The restriction of F. nickliniana to limestone-rich regions suggests a requirement for high calcium concentration or some other correlate of water hardness.

> Taxonomy & Systematics

Hydrobioids of the subfamily Fontigentinae bear a rather striking multiply-lobed penis.  While their species-level taxonomy has been stable since the monograph of Hershler and colleagues (1990), their assignment to the Hydrobiidae (ss) by Wilke et al. (2013) was rather tentative.

> Supplementary Resources [PDF]

• Hydrobiid distribution in Atlantic drainages (2013)
• Hydrobiid distribution in eastern Tennessee River drainages (2011)
• Virginia species account with county distribution (2011)

> Essays

• A photo comparing living F. nickliniana to Fontigens orolibas is available from my blog post of 26July06 entitled "Springsnails of the Blue Ridge."
• Earlier versions of this website, online until August of 2016, adopted the large, broadly-inclusive concept of the Hydrobiidae (sl) following Kabat & Hershler (1993).  More recently the FWGNA project has shifted to the Wilke et al. (2013) classification system, distinguishing a much smaller Hydrobiidae (ss) and elevating many hydrobioid taxa previously ranked as subfamilies to the full family level.  For more details, see The Classification of the Hydrobioids.

> References

Berry, E. G. (1943)  The Amnicolidae of Michigan: Distribution, ecology, and taxonomy.  Misc. Publ. Mus. Zool. Univ. Mich. 57: 1 - 68.
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. 
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.
Wilke T., Haase M., Hershler R., Liu H-P., Misof B., Ponder W. (2013)  Pushing short DNA fragments to the limit: Phylogenetic relationships of “hydrobioid” gastropods (Caenogastropoda: Rissooidea).  Molecular Phylogenetics and Evolution 66: 715 – 736.