Archaeopotamus
...that Archaeopotamus is the oldest well-identified genus of hippos, having lived 7.5 million to 1.8 million years ago?
...that <b id="mwCkw"><a href="./Archaeopotamus" id="mwCk0" rel="mw:WikiLink" title="Archaeopotamus">Archaeopotamus</a></b> is the oldest well-identified <a href="./Genus" id="mwCk4" rel="mw:WikiLink" title="Genus">genus</a> of <a href="./Hippopotamidae" id="mwCk8" rel="mw:WikiLink" title="Hippopotamidae">hippos</a>, having lived 7.5 million to 1.8 million years ago?