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.
The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte. It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale is dated as Cambrian Series 2, Stage 4, correlated with the upper Botomian Stage of the Lower Cambrian.
Ananaspis is a genus of trilobite in the order Phacopida, which existed in what is now the Czech Republic. It was described by Campbell in 1967, and the type species is Ananaspis fecundis, which was originally described as Phacops fecundus communis by Barrande in 1852.
Burmeisteria is a genus of trilobites in the order Phacopida that existed during the lower Devonian in what is now South Africa. It was described by Salter in 1865, and the type species is Burmeisteria herschelii, which was originally described under the genus Homalonotus by Murchison in 1839. It also contains the species B. accraensis, B. acuminata, and B. noticus. The type locality was the Bokkeveld Group.
Cromus is a genus of phacopid trilobites in the family Encrinuridae, that existed during the upper Silurian in what is now the Czech Republic. The genus was described by Barrande in 1852, and the type species is C. intercostatus. It also contains the species C. canorus.
Cybelopsis is a trilobite in the order Phacopida, that existed during the lower Ordovician in what is now Greenland. It was described by Poulsen in 1927, and the type species is Cybelopsis speciosa. The type locality for the genus was the Nunatami Formation.
Denckmannites is a trilobite in the order Phacopida, that existed during the upper Silurian in what is now the Czech Republic. It was described by Wedekind in 1914, and the type species is Denckmannites volborthi, which was originally described under the genus Phacops by Barrande in 1852. It also contains the species Denckmannites morator, and Denckmannites primaevus. The type locality was the Kopanina Formation.
Dipleura is a genus of trilobites in the order Phacopida. It was described by Green in 1832, and the type species is Dipleura dekayi. The type locality was in the Hamilton Group in New York.
Encrinurella is a genus of trilobite in the order Phacopida, that existed during the middle Ordovician in what is now Burma. It was described by Reed in 1915, and the type species is Encrinurella insangensis, which was originally described under the genus Pliomera by Reed in 1906. The type locality was the Naungkangyi Beds.
Encrinuroides is a genus of trilobites in the order Phacopida, that existed during the upper Ordovician in what is now Wales. It was described by Reed in 1931, and the type species is Encrinuroides sexcostata, which was originally described under the genus Cybele by Salter in 1848. It also contains the species, Encrinuroides enshiensis, Encrinuroides insularis, and Encrinuroides rarus. The type locality was in the Sholeshook Limestone Formation.
Eodalmanitina is a trilobite in the order Phacopida, that existed during the middle Ordovician in what is now France. It was described by Henry in 1964, and the type species is Eodalmanitina macropthalma, which was originally described under the genus Calymene by Brongniart in 1822. The type locality was in Loire-Atlantique.
Forteyops is a genus of trilobites in the order Phacopida, that existed during the lower Ordovician in what is now the United States. It was described by Pribyl and Vanek in 1985, and the type species is Forteyops sexapugia, which was originally described under the genus Kawina by Ross in 1951. The type locality was the Garden City Formation in Utah.
Heliomeroides is a trilobite in the order Phacopida, that existed during the upper Ordovician in what is now the United States. It was described by Evitt in 1951, and the type species is Heliomeroides teres. The type locality was the Lincolnshire Formation in Virginia.
Hintzeia is a genus of trilobites in the order Phacopida, that existed during the lower Ordovician in what is now the United States. It was described by Harrington in 1957, and the type species is Hintzeia aemula, which was originally described under the genus Protopliomerops by Hintze in 1953. Harrington also moved two other Protopliomerops species, P. celsaora and P. firmimarginis, under Hintzeia. The generic name is derived from that of the type species' author. The type locality was the Fillmore Formation in Utah.
Kanoshia is a genus of trilobites in the order Phacopida, that existed during the middle Ordovician in what is now Utah, USA. It was described by Harrington in 1957, and the type species is Kanoshia kanoshensis, which was originally described under the genus Pseudomera by Hintze in 1953. It also contains the species K. depressus and K. reticulata. The generic name is derived from the type species' epithet, which in turn is derived from the name of the type locality, the Kanosh Formation.
Kayserops is a trilobite in the order Phacopida, that existed during the lower Devonian in what is now Germany. It was described by Delo in 1935, and the type species is Kayserops kochi, which was originally described under the genus Cryphaeus by Kayser in 1883. The generic name is derived from the name of the species' author. The type locality was the Rhenish Massif.
The Walcott–Rust quarry, in Herkimer County, New York, is an excellent example of an obrution Lagerstätte. Unique preservation of trilobite appendages resulted from early consolidation (cementation) of the surrounding rock, followed by spar filling of the interior cavity within the appendages. The presence of so many well preserved trilobites in one location alone qualifies the beds as an exceptional trilobite site, but the beds are further distinguished as the source of the first trilobites for which appendages were definitively described.
The cephalon is the head section of an arthropod. It is a tagma, i.e., a specialized grouping of arthropod segments. The word cephalon derives from the Greek κεφαλή (kephalē), meaning "head".
Micragnostus is a genus of trilobite in the order Agnostida, which existed in what is now north Wales. It was described by Howell in 1935, and the type species is Micragnostus calvus, which was originally described as a species of Agnostus by Lake in 1906.
Bumastus is an extinct genus of corynexochid trilobites which existed from the Early Ordovician period to the Late Silurian period. They were relatively large trilobites, reaching a length of 6 in (15 cm). They were distinctive for their highly globular, smooth-surfaced exoskeleton. They possessed well-developed, large compound eyes and were believed to have dwelled in shallow-water sediments in life.
