Tag Archives: Gastrocopta

Gastrocopta contracta

Gastrocopta contracta, Bruce Peninsula National Park, Ontario

Gastrocopta contracta, Bruce Peninsula National Park, Ontario. Shell 2.7 mm.

I have to admit a fasciation with the Gastrocopta, a.k.a. “Snaggletooths”. The genus seems so foreign to me, and in a way it is. Here in British Columbia, there seems to be just one species, G. holzingeri, and it is rare! The pattern in Canada is that Ontario has the most Gastrocopta species (seconded by Quebec), with decreasing numbers of species east and west of Central Canada.

Seen here is Gastrocopta contracta, the Bottleneck Snaggletooth, known from Manitoba to at least western Quebec. Insofar as Gastrocopta go, this species is very distinctive. The conical spire and narrowed last whorl that is produced into a projecting, vaguely triangular aperture are diagnostic. The “folds” (aka, plicae, lamellae, denticles, etc. … whatever terminology you use) within the aperture give the appearance of almost blocking the opening, and hence the name.

The pale colour of Gastrocopta shells is so not widespread in Canadian micro-snails (in older literature: having the colour of “spermaceti” — a waxy substance in the head of whales according to Wikipedia),*  But, shells of this and other species often are plastered with dirt and debris, making them almost unrecognizable as snails, such as the well-camouflaged G. tappaniana in a photo in a previous post.

*This is a case where old descriptions use terminology that no longer has as much meaning as it once did, since when was the time you came across a jar (did it come in jars?) of spermaceti to compare with snails’ colour?