Fine-lined Pocketbook (Hamoita altilis)
Formerly Lampsilis altilis, the fine-lined pocketbook is a species of freshwater Unionid bivalve which is endemic to the United States. Like most bivalves, H. altilis is a filter feeder, filtering the water around it for nutrients.
Currently the Fine-lined Pocketbook is listed as Endangered by the IUCN as it faces threats from a restricted range and habitat destruction.
Image: Dick Biggins