Discus macclintocki
Overview
 
The Iowa Pleistocene snail, also known as the Pleistocene disk, scientific name Discus macclintocki, is a very small air-breathing land snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...

 pulmonate gastropod mollusk.

This snail now occurs nowhere else in the world but a few specialized locations: 37 algific talus slope
Algific talus slope
Algific talus slopes comprise a very rare, fragile ecosystem and habitat stated to exist only in the Driftless Area of Minnesota, Wisconsin, Illinois, and especially, Iowa...

s in Iowa
Iowa
Iowa is a state located in the Midwestern United States, an area often referred to as the "American Heartland". It derives its name from the Ioway people, one of the many American Indian tribes that occupied the state at the time of European exploration. Iowa was a part of the French colony of New...

 and Illinois
Illinois
Illinois is the fifth-most populous state of the United States of America, and is often noted for being a microcosm of the entire country. With Chicago in the northeast, small industrial cities and great agricultural productivity in central and northern Illinois, and natural resources like coal,...

. Algific talus slopes are areas of talus or scree that are "cold-producing", in other words they are part of a natural air-exchange system that renders the microclimate
Microclimate
A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

 there colder than it is in the immediately surrounding areas.
 
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