Arcidens confragosus

Arcidens confragosus is a species of freshwater mussels in the family Unionidae, the river mussels. It is commonly known as the rock pocketbook,^[1][2] but also has many other common names: bastard, black pocketbook, grandmaw, queen, and rockshell.^[1]

Rock pocketbook
A live individual of Arcidens confragosus
Conservation status
Least Concern  (IUCN 3.1)[1]
Apparently Secure  (NatureServe)[2]
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Bivalvia
Order:	Unionida
Family:	Unionidae
Genus:	Arcidens
Species:	A. confragosus
Binomial name
Arcidens confragosus (Say, 1829)
Synonyms
Alasmidonta confragosus (basionym) Margaritana confragosus Complanaria confragosus Baphia confragosus Unio confragosus

Distribution

This species is widespread in central parts of the United States: it occurs in the Mississippi River drainage and in coastal rivers draining to the Gulf of Mexico, from the Colorado River in Texas east to the Mobile River System in Alabama.^[1]

Description

The shell is "pyriform" or pear-shaped, heavily sculptured, but fairly thin, up to 15 centimetres (5.9 in) long. The shell is green to dark brown. The nacre is white, iridescent.