The Early Cretaceous period lasted from 144 million years ago to 97 million years ago. The Late Cretaceous period lasted from 97 to 65 million years ago. Crinoid Crinoids are echinoderms, a group of animals that also includes the sea-urchins and starfish. Their superficial flower-like appearance led to their popular name . In the Palaeozoic era crinoids were abundant but they started to decline during the Mesozoic era.
Today there are only a few, mostly free-swimming, forms.
They have changed very little in their history, nearly all being aquatic or semi-aquatic hunters and scavengers. Crustacean A class of arthropods that includes crabs, lobsters, wood-lice, barnacles and waterfleas. They evolved in the Cambrian period, or maybe even earlier, and became diverse and numerous in the Mesozoic era. Cryolophosaurus Cryolophosaurus, meaning . It had a horn-like, upward pointing crest above its eyes.