Pilina unguis
... that the Paleozoic monoplacophoran Pilina unguis was twice as large as any known living monoplacophoran?
... that the <a href="./Paleozoic" id="mwA_I" rel="mw:WikiLink" title="Paleozoic">Paleozoic</a> <a href="./Monoplacophora" id="mwA_M" rel="mw:WikiLink" title="Monoplacophora">monoplacophoran</a> <i id="mwA_Q"><b id="mwA_U"><a href="./Pilina_unguis" id="mwA_Y" rel="mw:WikiLink" title="Pilina unguis">Pilina unguis</a></b></i> was twice as large as any known living monoplacophoran?