Phylum Brachiopoda Duméril, 1806 - brachiopods Subphylum Rhynchonelliformea Williams et al., 1996 Class Rhynchonellata Williams et al., 1996 Order Terebratulida Waagen, 1883 Suborder Terebratellidina Muir-Wood, 1955 Superfamily Megathyridoidea Dall, 1870 Family †Praeargyrothecidae MacKinnon & Smirnova, 1995