You never know, but I doubt it. Those animals went extinct millions of years ago; we don't know how long they lived, but it certainly isn't that long. And there would have to be at least a few hundred for the species to go on; they can't just breed with their family, or else the babies will have recessive traits. And even if there were hundreds of them, I really think we'd have noticed by now.
Also, forgive me if I sound like an idiot when I'm talking about genetics. When it comes to genetics, I am LOL