Trilobites are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last trilobites disappeared in the mass extinction at the end of the Permian about 251.9 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Ptychopariida is a large, heterogeneous order of trilobite containing some of the most primitive species known. The earliest species occurred in the second half of the Lower Cambrian, and the last species did not survive the Ordovician–Silurian extinction event.
Proetida is an order of trilobite that lived from the Ordovician to the Permian. It was the last surviving order of trilobite, dying out in the Permian-Triassic extinction event.
Endops yanagisawai is a proetid trilobite belonging to the family Proetidae, endemic to Middle Permian-aged marine strata in Fukushima Prefecture, Japan. It was originally described by Riuji Endo as Paladin yanagisawai.
Proetidae is a family of proetid trilobites. The first species appeared in the Upper Ordovician, and the last genera survived until the Middle Permian. However, if the closely related family Phillipsiidae is actually a subfamily of Proetidae, then the proetids of Proetidae survive until the end of the Permian, where the last perish during the Permian–Triassic extinction event.
Cummingella is a genus of proetid trilobite in the family Phillipsiidae that lived from the earliest Carboniferous until the last species' extinction in the Middle Permian. Fossils have been found in corresponding marine strata of western Europe, the United Kingdom, and the United States.
Proetus is a genus of proetid trilobite found in Silurian-aged marine strata of Europe.
Nipponaspis is a genus of proetid trilobite belonging to the family Phillipsiidae. Fossils of the various species are found in Middle Permian-aged marine strata of Fukushima Prefecture, Japan, China, Korea, and Alaska.
Thaiaspis is a genus of proetid trilobite belonging to the family Phillipsiidae. Fossils of the various species are found in Middle to Late Mississippian-aged marine strata of eastern Asia, especially of Carboniferous-aged marine strata in Thailand.
Vidria vespa is a proetid trilobite belonging to the family Phillipsiidae. The fossils are found in Middle Permian-aged marine strata of Western Texas. It is unique among Permian-aged trilobites in having a posterior spine emanating from the pygidium of the adult.
Gitarra is a genus of trilobite in the family Proetidae that lived between the late Tournaisian and Late Westphalian of the Carboniferous period.
Malchi magnificus is a proetid trilobite belonging to the family Phillipsiidae. The exquisitely preserved fossils are found in Lower Carboniferous-aged marine strata of what is now Malchi Creek, Queensland, Australia.
Librostoma is a subclass of trilobites defined by having a natant hypostome, which is a hypostome that is free from the anterior doublure and aligned with the anterior of the glabella, this is unlike a conterminant hypostome, which is attached to the exoskeleton.
Gerastos is a genus of proetid trilobite in the family Proetidae that lived between the Pragian and Eifelian of the Lower-Middle Devonian, spanning approximately 21 million years.
Ameura is an extinct genus of trilobite belonging to the family Proetidae. Fossils from the genus have been found in late Paleozoic beds in North America.
Anisopyge is an extinct genus of trilobite belonging to the order Proetida and family Phillipsiidae. Specimens have been found in Permian beds in North and Central America.
Kathwaia is a genus of trilobite known from the late Permian of Pakistan. It is notable for being one of the five last-known trilobites.
Proetoidea is a superfamily of trilobites in the order Proetida.
Paraphillipsia is a genus of proetid trilobite in the family Phillipsiidae. It is notable for being one of the last trilobites to go extinct during the Permian–Triassic extinction event.
Cummingellinae is a subfamily of trilobites in the family Phillipsiidae. They were common in shallow waters in the early Carboniferous of Europe. One of the last genera of trilobite, Paraphillipsia, was a cummingelline, making this group one of the last trilobites.
