By the Late Triassic the small cynodonts included the rodent-like tritylodonts ( possibly related to or descended from traversodonts ) , and the tiny , shrew-like , trithelodonts , which evolved into the first mammals .
By the Upper Triassic the small cynodonts included the rodent-like tritylodonts ( possibly related to or descended from travsersodonts ) , and the tiny , shrew-like , trithelodonts , which evolved into the first mammals .