Invertebrate Fossils in National Parks

Arthropods have segmented bodies and external skeletons. Trilobites and ostracodes are the most common marine arthropod fossils in national parks. Fossils of insect and spiders are quite rare in parks except at Florissant Fossil Beds National Monument where fine-grained shales provided the perfect c

Brachiopods are one of the most common marine invertebrate fossils found in Paleozoic rocks in national parks. They were a dominant group of marine organisms during the Paleozoic, filling many of the ecological niches in Paleozoic oceans that bivalves have occupied since the end of Permian extinctio

Crinoids are the most common echinoderm fossils in national parks, found mostly in Paleozoic rocks. Echinoderms have 5-sided symmetry and have skeletons composed of numerous small pieces, which break apart after death. Thus, most echinoderm fossils are only small bits of the larger organism.

Graptolites are important index fossils for the early Paleozoic. They look like pencil marks on rock faces but are the remains of tiny colonial animals. Graptolite fossils are known from a handful of national parks.