''Theliderma stapes'', the stirrup shell or stirrupshell, was a species of bivalve in the family

Unionidae The Unionidae are a family of freshwater mussels, the largest in the order Unionida, the bivalve molluscs sometimes known as river mussels, or simply as unionids. The range of distribution for this family is world-wide. It is at its most divers ...

. It was

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to eastern

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

and western

Alabama (We dare defend our rights) , anthem = "Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,765 ...

in the United States. It was last observed in 1987 and was proposed for delisting due to extinction by the

US Fish and Wildlife Service The United States Fish and Wildlife Service (USFWS or FWS) is an agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats. The mission of the agency is "working with othe ...

in 2021.

Conservation

This species experienced a population collapse primarily due to river modification in the form of canal construction. In 1976, it was predicted that the construction of the

Tennessee–Tombigbee Waterway The Tennessee–Tombigbee Waterway (popularly known as the Tenn-Tom) is a artificial U.S. waterway built in the 20th century from the Tennessee River to the junction of the Black Warrior-Tombigbee River system near Demopolis, Alabama. The Tenne ...

would cause the extinction of this species. This prediction would quickly come to fruition after the waterway was completed in 1984. Freshly dead shells of this species were last observed in 1987 and further surveys have failed to find any evidence of a surviving population. In 2021, it was proposed to delist this species from the Endangered Species Act. This is done when further efforts to recover a species would almost certainly be futile, and there is no evidence of currently surviving individuals. This species is likely now extinct.

References

stapes The ''stapes'' or stirrup is a bone in the middle ear of humans and other animals which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the foo ...

Endemic molluscs of the United States Critically endangered fauna of the United States Bivalves described in 1831 Taxonomy articles created by Polbot {{Unionidae-stub