Yonginella, a new bivalve (Mollusca) from the Silurian of Gotland

A new bivalve, Yonginella amica n. gen. and sp., is described from the Silurian of Gotland. Although it has a straight hinge line with cardinal and lateral teeth indicating relationship with the Cyrtodontidae of the Arcoida, its external morphology (with a conspicuous diagonal ridge and sulcus) differs considerably from all previously described taxa of this group. Yonginella amica exhibits a shell shape suitable for soft muddy bottoms (“snowshoe” adaptation), and is interpreted to have been a nonsiphonate suspension feeder with a semi-infaunal, byssate mode of life.