Plaesiomyidae is a family of extinct lamp shells belonging to the order Orthida.
Fossil record Fossils of Plaesiomyidae are found in marine strata from the Ordovician until the Silurian (age range: from 478.6 to 418.7 years ago.). Paleobiology Database
Genera †Austinella Foerste, 1909 †Bokotorthis Popov et al., 2000 †Campylorthis Ulrich and Copper, 1942 †Chaulistomella †Dinorthis Hall and Clarke, 1892 †Evenkina †Madiorthis Zuykov and Harper, 2008 †Metorthis †Multicostella †Plaesiomys Hall and Clarke, 1892 †Retrorsirostra Schuchert and Cooper, 1932 †Valcourea
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