Phylum Gnathostomulida Ax, 1956 - gnathostomulids Order Filospermoidea Sterrer, 1972 Family Pterognathiidae Sterrer, 1972 Genus Pterognathia Sterrer, 1966 Pterognathia atrox Sterrer, 1969 Pterognathia meixneri Sterrer, 1969 Pterognathia sorex Sterrer, 1969 Pterognathia swedmarki Sterrer, 1966