Lophospira jaekeli (FOSSIL) E.F.R.K. Koken& J. Perner, 1925 †
Donaldiella karczewskii (FOSSIL) Krawczynski, 2002 †
Worthenia kingi (FOSSIL) Batten, 1989 †
Lophospira kinosakii (FOSSIL) Kobayashi, 1934 †
Worthenia klamathensis (FOSSIL) Smith, 1927 †
Itimaspira klugi (FOSSIL) Heidelberger & al.,2009 †
Lophospira kuckersiana (FOSSIL) (Teichert, 1932 †)
Ruedemannia laevissima (FOSSIL) (Lindström, 1884 †)
Worthenia lantenoisi (FOSSIL) Mansuy, 1913 †
Longstaffia laqueata (FOSSIL) (Lindström, 1884 †)
Worthenia latialveozona (FOSSIL) Batten, 1989 †
Worthenia legrandi (FOSSIL) B.S. Kues & Batten,2001 †
Worthenia liebeneri (FOSSIL) (Laube, 1868 †)
Worthenia ligylirae (FOSSIL) Yin & E.L. Yochelson,1983 †
Ruedemannia lirata (FOSSIL) (Ulrich & Scofield,1897 †)
Lophospira lyckholmiensis (FOSSIL) Teichert, 1932 †
Gyronema lyratum (FOSSIL) Ulrich & Scofield, 1897 †
Worthenia magna (FOSSIL) Böhm, 1895 †
Lophospira major (FOSSIL) (J.W. Hall, 1852 †)
Paupospira manitouliensis (FOSSIL) (Foerste, 1924 †)
Lophospira manitoulinensis (FOSSIL) Foerste, 1924 †
Manzanospira manzanicum (FOSSIL) (Girty, 1909 †)
Worthenia margaritacea (FOSSIL) (Laube, 1868 †)
Worthenia marmolatae (FOSSIL) E.A.L. Kittl, 1894 †
Lophospira mickwitzi (FOSSIL) E.F.R.K. Koken, 1896 †
Proturritella microclathrata (FOSSIL) Hudson, 1905 †
Lophospira milleri (FOSSIL) (Miller, 1877 †)
Yochelsonospira mississippiensis (FOSSIL) (White & R.P. Whitfield,1862 †)
Lophospira modesta (FOSSIL) (Billings, 1857 †)
Ectomaria mongolica (FOSSIL) A.W. Grabau 1931 †
Paupospira moorei (FOSSIL) (Ulrich & Scofield,1897 †)
Worthenia multicarinata (FOSSIL) (Mansuy, 1912 †)
Ectomaria multicostata (FOSSIL) I. Hayasaka 1943 †
Frodospira munda (FOSSIL) (Lindström, 1884 †)
Worthenia nana (FOSSIL) A.W. Grabau, 1931 †