The Cretaceous is unrelated with Paleogene extinction event.
 The other Cretaceous groups that did not survive into the Cenozoic Erathe ichthyosaurs, last remaining temnospondyls (Koolasuchus), and nonmammalian cynodonts (Tritylodontidae)  were already extinct millions of years before the event occurred
The Cretaceous (  krih-TAY-shs) is a geological period that lasted from about 145 to 66 million years ago (Mya)

