North-American Unionida of conservation concern in the Museo di Zoologia dell’Università di Bologna, Italy. A-B. Cyprogenia stegaria (Rafinesque, 1820), Critically Endangered (IUCN), Cumberland River, length 40 mm; C-D. Dromus dromas (Lea, 1834), Critically Endangered (IUCN), Endangered (USFWS), Cumberland River, length 64 mm; E-F. Epioblasma haysiana (Lea, 1834), Extinct (IUCN), Cumberland River, length 41 mm; G-H. Epioblasma torulosa (Rafinesque, 1820), Critically endangered (IUCN), Endangered (USFWS), Ohio River, length 56 mm; I-J. Lampsilis cariosa (Say, 1817), Endangered (IUCN), Delaware River, length 76 mm. Scale bar 1 cm.