Temür’s grandson Ulugh Beg states in his Chinggisid history that Oghuz Khan, from whom the Ottoman dynasty descends, is not to be confused with his namesake from whom the Chinggisids and Timurids descend.

Source (page 137):
Some remarks on the Turkicisation of the Mongols in post-Mongol Central Asia and the Qipchaq Steppe