Scaphohippus
... that the fossil horse Scaphohippus became extinct when tectonic barriers between the Great Plains and Great Basin of North America disappeared about 13 million years ago?
... that the <a href="./Fossil" id="mwD2U" rel="mw:WikiLink" title="Fossil">fossil</a> <a href="./Equidae" id="mwD2Y" rel="mw:WikiLink" title="Equidae">horse</a> <i id="mwD2c"><b id="mwD2g"><a href="./Scaphohippus" id="mwD2k" rel="mw:WikiLink" title="Scaphohippus">Scaphohippus</a></b></i> became extinct when tectonic barriers between the <a href="./Great_Plains" id="mwD2o" rel="mw:WikiLink" title="Great Plains">Great Plains</a> and <a href="./Great_Basin" id="mwD2s" rel="mw:WikiLink" title="Great Basin">Great Basin</a> of <a href="./North_America" id="mwD2w" rel="mw:WikiLink" title="North America">North America</a> disappeared about 13 million years ago?