Neoephemera antiqua
... that the oldest known member of the mayfly family Neoephemeridae is the Eocene species Neoephemera antiqua?
... that the oldest known member of the <a href="./Mayfly" id="mwB38" rel="mw:WikiLink" title="Mayfly">mayfly</a> family Neoephemeridae is the <a href="./Eocene" id="mwB4A" rel="mw:WikiLink" title="Eocene">Eocene</a> species <i id="mwB4E"><b id="mwB4I"><a href="./Neoephemera_antiqua" id="mwB4M" rel="mw:WikiLink" title="Neoephemera antiqua">Neoephemera antiqua</a></b></i>?