Cratochelone
... that at an estimated 4 metres (13 ft), Cratochelone is the largest of the three extinct protostegid sea turtles found in Australia?
... that at an estimated <span about="#mwt38" data-mw='{"parts":[{"template":{"target":{"wt":"convert","href":"./Template:Convert"},"params":{"1":{"wt":"4"},"2":{"wt":"m"},"3":{"wt":"ft"}},"i":0}}]}' id="mwCuk" typeof="mw:Transclusion">4 metres (13</span><span about="#mwt38" typeof="mw:Entity"> </span><span about="#mwt38">ft)</span>, <i id="mwCuo"><b id="mwCus"><a href="./Cratochelone" id="mwCuw" rel="mw:WikiLink" title="Cratochelone">Cratochelone</a></b></i> is the largest of the three extinct <a href="./Protostegidae" id="mwCu0" rel="mw:WikiLink" title="Protostegidae">protostegid</a> sea turtles found in Australia?