It lived during the Campanian stage of the Late Cretaceous , however , some fragmentary remains such as teeth which may belong to this genus have been found from the late Maastrichtian age Lance and Hell Creek Formations , dating to 66 million years ago .
It lived during the Upper Cretaceous ; some fragmentary remains such as teeth which may belong to this genus have been found from the latest Cretaceous , 65.5 million years ago .