The speckled pocketbook, scientific name Lampsilis streckeri, 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 mussel in the family Unionidae

Unionidae

Unionidae is a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, naiads, or simply as unionids.The range of distribution for this family is world-wide...

, the river mussels. It is endemic to Arkansas

Arkansas

Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...

 in the United States, where it is threatened by habitat loss. 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 mussel is about 8 centimeters long. It is dark yellow to brown and has chevron

Chevron

Chevron may refer to:* Chevron , a decoration* Chevron , a bone* Chevron , a fold in rock layers* Chevron , a sediment deposit across the earth's surface* The Chevron, a newspaper...

-shaped spots and chainlike rays. It is sexually dimorphic

Sexual dimorphism

Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...

, the females being more rounded at the posterior.

When this species was placed on the Endangered Species List it was limited to a six-mile strech of the Middle Fork of the Little Red River in Arkansas. The dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

ming of the river to form the Greers Ferry Reservoir changed the hydrology of the river, altering the habitat.

Since its listing several additional populations have been discovered in the river.

Source

• Bogan, A.E. 2000. Lampsilis streckeri. 2011 IUCN Red List of Threatened Species. Downloaded on 27 September 2011.