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 extant trilobites finally 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.
Deiphon is a distinctive genus of Silurian phacopid trilobites of the family Cheiruridae found in Western and Central Europe, and in Central and Eastern United States. The type species, D. forbesi, from England, Bohemia, and Sweden, was discovered and described by the French paleontologist, Joachim Barrande in 1850.
Tsunyidiscus is a trilobite belonging to the Suborder Eodiscina. Tsunyidiscus appeared near the end of the Lower Cambrian, during the late Atdabanian stage of geologic time and some collections suggest it may have survived into the Botomian. The genus is very small, oculate and isopypous with a narrow dome-shaped glabella and a narrow bullet-shaped pygidial axis. Thorax consists of three segments. Tsunyidiscus is the only genus currently attributed to the family Tsunyidiscidae.
Marrellomorpha are an extinct group of arthropods known from the Cambrian to the Early Devonian. They lacked mineralised hard parts, so are only known from areas of exceptional preservation, limiting their fossil distribution. The best known member is Marrella, with thousands of specimens found in the Cambrian aged Burgess Shale of Canada. The group is divided up into two major orders, Marrellida and Acercostraca. Marrellida is recognised by the possession of head shields with two or three pairs of elongate spine-like projections, and three pairs of uniramous appendages on the cephalon, while Acercostraca generally have large ovoid carapaces that cover the entire upper half of the body, and five pairs of uniramous cephalic appendages. Both groups have unbranched antennules and a segmented trunk with biramous appendages. Recent research has suggested the previously enigmatic Cambrian trilobite-like arthropods Skania and Primicaris belong to this group. Their phylogenetic position is uncertain, various studies have alternatively placed them in the Arachnomorpha as relatives of Artiopoda, as related to Mandibulata, or as stem group euarthropods.
Lonchodomas is a genus of trilobites, that lived during the Ordovician. It was eyeless, like all raphiophorids, and had a long straight sword-like frontal spine, that gradually transforms into the relatively long glabella. Both the glabellar spine and the backward directed genal spines are subquadrate in section. Lonchodomas has five thorax segments and the pleural area of the pygidium has two narrow furrows. Lonchodomas occurred in what are today Argentina, Canada (Newfoundland), Estonia, Latvia, Norway, Sweden, the Russian Federation and the United States.
Soomaspis is a genus of small to average size marine arthropods in the Liwiidae Family, that lived during the late Ordovician. Fossil remains of Soomaspis were collected from the Soom Shale Lagerstätte in Western Cape, South Africa. Soomaspis looks like a large, soft agnostid trilobite. It has a headshield wider than the tailshield (pygidium), and in between them three thoracic body segments (somites). The genus is monotypic, its sole species being Soomaspis splendida.
Eodiscina is trilobite suborder. The Eodiscina first developed near the end of the Lower Cambrian period and became extinct at the end of the Middle Cambrian. Species are tiny to small, and have a thorax of two or three segments. Eodiscina includes six families classified under one superfamily, Eodiscoidea.
Trinodus is a very small to small blind trilobite, a well known group of extinct marine arthropods, which lived during the Ordovician, in what are now the Yukon Territories, Virginia, Italy, Czech Republic, Poland, Denmark, Sweden, Svalbard, Ireland, Scotland, Wales, Iran, Kazakhstan and China. It is one of the last of the Agnostida order to survive.
Sphaeragnostus is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It can be recognized by having two thorax segments, a totally effaced headshield, while the tailshield although effaced, has a clear furrow parallel to its border, and a short, convex, subcircular axis. It lived during the Ordovician.
Geragnostus is a genus of very small agnostid trilobites whose fossils are found Ordovician-aged marine strata from Eurasia, North America and Argentina.
Cyclopyge is a genus of small to average size trilobites that lived during the Ordovician. Like all members of the family Cyclopigidae, it has very large convex eyes, that cover most of the free cheeks, and in some species touch each other. The eyes almost touch the large glabella. The occipital ring has merged with the rest of the glabella. The glabella does not extend into a frontal thorn. The cephalon lacks genal spines. The 6 thorax segments have short pleurae. The pygidium is rather large, and often rather effaced. These are features that also occur in other Cyclopygidae, and are indications of a pelagic lifestyle.
Symphysops is a genus of trilobites of average size, belonging to the Cyclopygidae family. It had a cosmopolitan distribution and lived from the Middle to the Upper Ordovician. It has been found in Canada, China, the Czech Republic (Bohemia), Iran, Ireland, Kazakhstan, Poland, Morocco, Spain, Scotland and Wales. The name Symphysops refers to the fused eyes, common to the species of this genus. Some (sub)species of the cyclopygid genera Cyclopyge and Pricyclopyge share this character, but Symphysops uniquely combines the merged eye with a frontal thorn on the head and the "lower eyelid".
Pricyclopyge is a genus of trilobites assigned to the family Cyclopygidae that occurs throughout the Ordovician. Pricyclopyge had an extratropical distribution, and there is evidence that it lived in darker parts of the water column. Pricyclopyge has huge eyes, an inverted pear-shaped glabella, six thorax segments, with on the 3rd two small discs. Pricyclopyge is known from what are today China, the Czech Republic, France, and the United Kingdom.
Carolinites is a genus of trilobite, assigned to the Telephinidae family, that occurs during the Lower and Middle Ordovician. Carolinites had a pantropical distribution, and there is evidence that it lived in upper parts of the water column. The free cheeks of Carolinites are largely covered by its huge eyes, except for the attachment of large genal spines that extend downward, backward and lateral and gradually curving further backward. The glabella is slightly bulbous, the occipital ring is well defined, but further transglabellar furrows are lacking. The thorax has 10 segments. The axis of the pygidium is highly vaulted, with a curved spine emerging almost perpendicular to the midline and ending parallel to it and a node on each of the other three segments. Carolinites is known from what are today Australia (Tasmania), Canada (Alberta), China, France, Spitsbergen, and the United States (Utah).
Raphiophoridae is a family of small to average-sized trilobites that first occurred at the start of the Ordovician and became extinct at the end of the Middle Silurian.
Cnemidopyge is a genus of trilobites that lived during the Ordovician. Like all Raphiophorids it is blind, with a cephalon that is subtriangular to subsemicircular, carrying genal spines and a forward directed rapier-like spine on the central raised area, with the front of the glabella inflated and the natural fracture lines of the cephalon coinciding with its margin. It may be easily distinguished from other raphiophorids by the rectangular thorax with 6 segments, where other genera have a different number of segments and segments change in width over the length of the thorax. Uniquely in this genus, the inner pleural region of the frontal segment is enlarged. Also the axis and pleural fields of the pygidium are strongly segmented.
Taklamakania is a genus of asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. Like all raphiophorids it is blind, with a headshield that is subsemicircular, carrying genal spines and a forward directed spine on the central raised area, with the front of the glabella inflated and the natural fracture lines of the cephalon coinciding with its margin. It is easily distinguished from most other raphiophorids by the 3 thorax segments. Pseudampyxina, Nanshanaspis, and Kongqiangheia also have only 3 such segments, but all three lack the frontal spine that emanates from the glabellum of Taklamakania species. All other raphiophorid genera have at least 5 thorax segments. Three species, T. tarimensis, T. tarimheensis, and T. xinjiangensis, have been assigned to this genus so far.
This list of fossil arthropods described in 2014 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2014. The list only includes taxa at the level of genus or species.
Entomaspididae is a family of harpetid trilobites that ranges from the Upper Cambrian to Lower Ordovician of marine strata in China and the United States.
Nanshanaspis is a genus of asaphid trilobites of the family Raphiophoridae that lived during the late Caradoc of Inner Mongolia, China. Like all raphiophorids it is blind, with a headshield that is subsemicircular, carrying genal spines and a forward directed spine on the central raised area, with the front of the glabella inflated and the natural fracture lines of the cephalon coinciding with its margin. It is easily distinguished from most other raphiophorids by the 3 thorax segments. Pseudampyxina, Taklamakania, and Kongqiangheia also have only 3 such segments, while all other raphiophorid genera have at least 5 thorax segments, leading to the erection of the subfamily "Taklamakaniinae" to contain these four genera. "Taklamakaniinae" was dissolved and its members absorbed into Raphiophorinae when further study showed the close similarities the "taklamakaniids" had to the juvenile forms of various raphiophorinids. Specimens of Nanshanaspis, for example, closely resemble juveniles of Globampyx trinucleoides.
