''Paraceraurus'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

trilobite Trilobites (; meaning "three-lobed entities") are extinction, extinct marine arthropods that form the class (biology), class Trilobita. One of the earliest groups of arthropods to appear in the fossil record, trilobites were among the most succ ...

s that lived in the

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

period (485.4 to 443.4 Ma). Its remains have been found in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Estonia Estonia, officially the Republic of Estonia, is a country in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the Baltic Sea across from Sweden, to the south by Latvia, and to the east by Ru ...

Sweden Sweden, formally the Kingdom of Sweden, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. It borders Norway to the west and north, and Finland to the east. At , Sweden is the largest Nordic count ...

and

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

.''Paraceraurus'' in the Paleobiology Database
/ref> These trilobites have a rounded and moderately convex ''

cephalon Cephalon, Inc. was an American biopharmaceutical company co-founded in 1987 by pharmacologist Frank Baldino Jr., Frank Baldino, Jr., neuroscientist Michael Lewis, and organic chemist James C. Kauer—all three former scientists with the DuPont ...

''. ''

Glabella The glabella, in humans, is the area of skin between the eyebrows and above the nose. The term also refers to the underlying bone that is slightly depressed, and joins the two brow ridges. It is a cephalometric landmark that is just superior ...

'' is convex or flattened, with a sub-rectangular outline. Thorax shows eleven segments.Fossilstock
/ref>

Selected species

* ''Paraceraurus aculeatus'' * ''

Paraceraurus exsul ''Paraceraurus exsul'' is a species of trilobite that lived in St. Petersburg Region and Tver Region (in erratic blocks) of Russia, Estonia, Finland (Åland, in erratic blocks), Sweden, North Germany (in erratic blocks), Lithuania and Belarus dur ...

'' * ''Paraceraurus gladiator'' * ''Paraceraurus ingricus'' * ''Paraceraurus macrophthalmus'' * ''Paraceraurus spinulosus''

References

* ''Trilobite: Eyewitness to Evolution'' by

Richard Fortey Richard Alan Fortey (15 February 1946 – 7 March 2025) was a British palaeontologist, natural historian, writer and television presenter, who served as president of the Geological Society of London for its bicentennial year of 2007. As a paleo ...

* Trilobites of the families Cheiruridae and Encrinuridae from Estonia.] Geoloogia Instituudi Uurimused rud Inst Geol Acad Sci Est SSRTallinn, 3 1958: 165–205, 210–212. oological Record Volume 95* V. Klikushin, A. Evdokimov, A. Pilipyuk. Ordovician Trilobites of the St. Petersburg Region, Russia, 2009. Cheiruridae Ordovician trilobites of North America Ordovician trilobites of Asia Phacopida genera {{phacopida-stub