Paleontology: the branch of science concerned with fossil animals and plants. Ichthyosaur: an extinct marine reptile from the Mesozoic era, resembling a dolphin. Plesiosaur: a large extinct marine reptile with a small head, long neck, and flippers. Pterosaur: a prehistoric flying reptile from the Mesozoic era. Coprolites: fossilized dung that provides information about the diet and environment of extinct organisms. Belemnites: an extinct group of marine cephalopods known for their bullet-shaped internal skeleton, which sometimes contained fossilized ink sacs similar to those of modern cephalopods.