| Cheirurina Temporal range: [1] | |
|---|---|
 | |
| Ceraurus pleurexanthemus (Cheiruridae) | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | † Trilobita |
| Order: | † Phacopida |
| Suborder: | † Cheirurina |
| Families | |
Cheirurina is a suborder of the trilobite order Phacopida. Known representatives range from the uppermost Cambrian (upper Furongian) to the end of the Middle Devonian (Givetian). [1] [2] Cheirurina is made up of a morphologically diverse group of related families.
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.
Phacopida ("lens-face") is an order of trilobites that lived from the Late Cambrian to the Late Devonian. It is made up of a morphologically diverse assemblage of taxa in three related suborders.
Phacopidae is a family of phacopid trilobites that ranges from the Lower Ordovician to the Upper Devonian, with representatives in all paleocontinents.
Calymene Brongniart, 1822, is a genus of trilobites in the order Phacopida, suborder Calymenina, that are found throughout North America, North Africa, and Europe in primarily Silurian outcrops. Calymene is closely related to Flexicalymene, and both genera are frequently found enrolled. Calymene trilobites are small, typically 2 cm in length. The cephalon is the widest part of the animal and the thorax usually has 13 segments.
Flexicalymene Shirley, 1936. is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and Family Calymenidae. Flexicalymene specimens can be mistaken for Calymene, Gravicalymene, Diacalymene and a few other Calymenina genera. They are used as an index fossil in the Ordovician. Ohio and North America are particularly known for being rich with Flexicalymene fossils.
Kainops is a genus of trilobites from the family Phacopidae, order Phacopida. It can be distinguished from Paciphacops by the greater number of facets to the eye. The form of the furrow between the palpebral area and the palpebral lobe also distinguishes Kainops from the genera Paciphacops and Viaphacops.
Toxophacops is a genus of trilobites from the order Phacopida, family Phacopidae. It is from the Devonian period and is very small compared to other genera in Phacopidae.
Calymenina is a suborder of the trilobite order Phacopida.
Eophacops is a genus of trilobites from the order Phacopida, family Phacopidae. These trilobites lived during the Middle Silurian in what are now North America and North-West Europe. Species assigned to this genus can be distinguished from Phacops by their small size (2–3 cm). Eophacops has very large eyes compared to the rest of its body.
Acastidae is a family of trilobites in the order Phacopida, suborder Phacopina, superfamily Acastoidea, containing the following genera:
Calmoniidae is a family of trilobites from the order Phacopida, suborder Phacopina, superfamily Acastoidea.
Acaste is a genus of extinct trilobite of the order Phacopida which lived throughout the Silurian period. Though many species had been included, it now has only one species, Acaste downingiae. It is characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles.
Acastava is an extinct genus of trilobite in the order Phacopida, from the upper Pragian to Emsian period of the Devonian.
Achatella is a genus of trilobite in the order Phacopida, which existed in what is now Ontario, Canada. It was named by Delo in 1935, and the type species is Achatella achates, which was originally assigned to the genus Dalmanites by Billings in 1860. Achatella also contains the species Achatella billingsi, and Achatella truncatocaudata.
Dienstina is a trilobite in the order Phacopida, that existed during the lower Devonian in what is now Germany. It was described by Richter and Richter in 1931, and the type species is Dienstina diensti, which the authors had originally assigned to the genus Phacopidella in 1923. The type locality was in Oberscheld, Rhenish Massif.
Encrinuridae is a family of trilobite within the order Phacopida that lived in what would be Africa, Asia, Australia, Europe, North America, and South America from the middle Ordovician to the early Devonian from 479 to 412.3 million years ago, existing for approximately 66.7 million years.
The Pterygometopidae are a family of trilobites, that is known from the Floian to the Katian (Ordovician), and reappears from the Telychian to the Sheinwoodian (Silurian). As part of the Phacopina suborder, its members have schizochroal eyes.
Calymene celebra is a Silurian species of trilobites of the order Phacopida and also the state fossil of Wisconsin. It is found in Illinois, Indiana, and Wisconsin.
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.
Gregory Donald Edgecombe is a merit researcher in the department of Earth Sciences at the Natural History Museum, London. He is a leading figure in understanding the evolution of arthropods, their position in animal evolution and the integration of fossil data into analyses of animal phylogeny. As a palaeontologist, he is also an authority on the systematics of centipedes – and a morphologist whose work contributes to the growth and methods of analysis of molecular datasets for inferring evolutionary relationships.
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