Phylum Gnathostomulida Ax, 1956 - gnathostomulids Order Bursovaginoidea Sterrer, 1972 Suborder Scleroperalia Sterrer, 1972 Family Rastrognathiidae R.M. Kristensen & A. Nørrevang, 1977 Genus Rastrognathia R.M. Kristensen & A. Nørrevang, 1977 Rastrognathia macrostoma R.M. Kristensen & A. Nørrevang, 1977