Marstonia ogmorhaphe is a rare species of freshwater snail

Freshwater snail

A freshwater snail is one kind of freshwater mollusc, the other kind being freshwater clams and mussels, i.e. freshwater bivalves. Specifically a freshwater snail is a gastropod that lives in a watery non-marine habitat. The majority of freshwater gastropods have a shell, with very few exceptions....

 known by the common names royal marstonia and royal springsnail. It is endemic to Tennessee

Tennessee

Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...

 in the United States, where it occurs in two streams in Marion County

Marion County, Tennessee

Marion County is a county located in the U.S. state of Tennessee. As of 2000, the population was 27,776. Its county seat is Jasper.Marion County is part of the Chattanooga, TN–GA Metropolitan Statistical Area.-Geography:According to the U.S...

. It is a federally listed endangered species

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 of the United States.

This gastropod, a member of the family Hydrobiidae

Hydrobiidae

Hydrobiidae, common name mud snails, is a large cosmopolitan taxonomic family of very small freshwater snails and brackish water snails that have an operculum, aquatic gastropod mollusks in the clade Littorinimorpha.- Distribution :...

, the mud snails, was first described in 1977. It is under 5 millimeters long. It lives in the diatom

Diatom

Diatoms are a major group of algae, and are one of the most common types of phytoplankton. Most diatoms are unicellular, although they can exist as colonies in the shape of filaments or ribbons , fans , zigzags , or stellate colonies . Diatoms are producers within the food chain...

aceous ooze

Pelagic sediments

Pelagic sediment or pelagite is a fine-grained sediment that has accumulated by the settling of particles through the water column to the ocean floor beneath the open ocean far from land. These particles consist primarily of either the microscopic, calcareous or siliceous shells of phytoplankton or...

 and debris in springs

Spring (hydrosphere)

A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...

. It is limited to the Sequatchie River

Sequatchie River

The Sequatchie River is a waterway that drains the Sequatchie Valley, a large valley in the Cumberland Plateau in Middle Tennessee.-Hydrography:The Sequatchie River's source is a massive spring which flows out of Head of Sequatchie Spring...

 Valley, where it lives in Blue Spring, the water supply for the town of Jasper, Tennessee

Jasper, Tennessee

Jasper is a town in Marion County, Tennessee. The population was 3,214 at the 2000 census. It is the county seat of Marion County.Jasper is part of the Chattanooga, TN–GA Metropolitan Statistical Area.-History:...

, and the stream just past the spring. It also lives in Owen Spring, four miles away.

This species is threatened by the degradation of water quality in its habitat, which is caused by coal mining

Coal mining

The goal of coal mining is to obtain coal from the ground. Coal is valued for its energy content, and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United States,...

and other processes.