Montana Field Guide

This ubiquitous, left-handed snail species is distributed in temerpate and sub-Arctic North America from southern Alaska and northwestern Canada (but not in the extreme north) east and southeast to central Labrador, western New England and the vicinity of New York City; south to central California, Nevada, Utah, and Colorado (Taylor 2003). (Burch 1989) lists several supposed synonyms including Physella gyrina gyrina from Canada, Quebec to Ontario south to Nebraska and east to New York. This snail can be found in a variety of habitats from lakes, ponds, streams, ditches, and marshes (Taylor 2003). Like most snails, these are herbivorous-scrapers of algae, detritus and diatoms from vegetation and off other benthic substrates.

If live specimens are being evaluated, this species may be distinguished from P. acuta easily by looking at the animals’ bodies. P. gyrina has very obvious whitish pigment spots on a dark grey ground, over the whole body including the tentacles, whereas P. acuta lacks spotting and ground color is more variable ranging from a pale grey to blue-grey or even black. The spire of P. gyrina is conical, flat sided, and the sutures between whorls is shallower, while the shell of P. acuta has a more rounded spire with less steep angles

No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

P. gyrina tends to live in clear to turbid waters in the marginal zones of large lakes, ponds, and rivers and can be found in the shallow margins or in marshy pools along shorelines

Like most snails, these are herbivorous- scrapers of algae, detritus and diatoms from other vegetation of benthic substrates

P. gyrina tends to live in clear to turbid waters in the marginal zones of large lakes, ponds and rivers and can be found in the shallow margins or in marshy pools along shorelines