Amnicola walkeri, common name Canadian duskysnail, is a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of freshwater 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...

, an aquatic

Aquatic animal

An aquatic animal is an animal, either vertebrate or invertebrate, which lives in water for most or all of its life. It may breathe air or extract its oxygen from that dissolved in water through specialised organs called gills, or directly through its skin. Natural environments and the animals that...

 gastropod mollusk in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Amnicolidae

Amnicolidae

Amnicolidae is a family of small freshwater snails with a gill and an operculum, aquatic gastropod mollusks.This family is in the superfamily Rissooidea and in the clade Littorinimorpha...

.

The name is in honor of Mr. Bryant Walker.

Shell description

The shell

Gastropod shell

The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...

 is thin, narrowly umbilicate, conic, shaped like Lyogyrus brownii Carpenter. The color of the shell is slightly yellowish corneous. The shell is thin, smooth, with faint growth-lines. The shell has 4 whorls

Whorl (mollusc)

A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...

 that are very convex and separated by deeply
constricting sutures. The last whorl

Body whorl

Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...

 is rounded below. The apex

Apex (mollusc)

Apex is an anatomical term for the tip of the mollusc shell of a gastropod, scaphopod, or cephalopod mollusc.-Gastropods:The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod...

 is obtuse.

The aperture

Aperture (mollusc)

The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....

 is oblique, rather small, mainly basal, a little longer than wide, but nearly circular. The inner margin is a trifle straightened above. The peristome is continuous, in contact with the preceding whorl for an extremely short distance above. Operculum

Operculum (gastropod)

The operculum, meaning little lid, is a corneous or calcareous anatomical structure which exists in many groups of sea snails and freshwater snails, and also in a few groups of land snails...

 is amnicoloid.

The width of the shell is 2-2.125 mm. The height of the shell is 2.33–3 mm. The width of aperture is 1-1.125 mm. The height of aperture is 1.08-1.25 mm.

Distribution

Type locality is Lake Michigan

Lake Michigan

Lake Michigan is one of the five Great Lakes of North America and the only one located entirely within the United States. It is the second largest of the Great Lakes by volume and the third largest by surface area, after Lake Superior and Lake Huron...

 at High Island Harbor, Beaver Island

Beaver Island (Lake Michigan)

Beaver Island is the largest island in Lake Michigan and part of the Beaver Island archipelago. Once home to a unique American monarchy, the island is now a popular tourist and vacation destination....

, at 10 meters depth.

Other localities include: Reed's Lake, Grand Rapids, Michigan; River Rouge

River Rouge (Michigan)

The River Rouge, also known as the Rouge River, is a river in the Metro Detroit area of southeastern Michigan. It flows into the Detroit River at Zug Island, which is the boundary between the cities of River Rouge and Detroit....

, Wayne County, Michigan.