Naraoiidae is a family, of extinct, soft-shelled trilobite-like arthropods, that belongs to the order Nectaspida. Species included in the Naraoiidae are known from the second half of the Lower Cambrian to the end of the Upper Silurian. The total number of collection sites is limited and distributed over a vast period of time: Maotianshan Shale and Balang Formation (China), Burgess Shale and Bertie Formation (Canada), the Šárka Formation, Emu Bay Shale (Australia), Idaho and Utah (USA). This is probably due to the rare occurrence of the right circumstances for soft tissue preservation, needed for these non-calcified exoskeletons.
Dalmanites is a genus of trilobite in the order Phacopida. They lived from the Late Ordovician to Middle Devonian.
Diacalymene is a genus of trilobite from the order Phacopida, suborder Calymenina. It includes the species D. ouzregui, D. clavicula, D. diademata and D. gabrielsi. It lived in the Ordovician and Silurian periods.
Naraoia is a genus of small to average size marine arthropods within the family Naraoiidae, that lived from the early Cambrian to the late Silurian period. The species are characterized by a large alimentary system and sideways oriented antennas.
Acaste is a genus of extinct trilobite of the order Phacopida which lived throughout the Silurian period. They are characterized by a convex dorsal surface, an absence of spines, a shortening of the head-shield and a general rounding off of all angles. Species include Acaste downingiae.
Cruziana is a trace fossil consisting of elongate, bilobed, approximately bilaterally symmetrical burrows, usually preserved along bedding planes, with a sculpture of repeated striations that are mostly oblique to the long dimension. It is found in marine and freshwater sediments. Cruziana has been extensively studied because it has uses in biostratigraphy, and because the traces can reveal many aspects of their makers' behavior.
Balizoma is a genus of trilobites from the family Encrinuridae. It has only been found in rocks of Silurian age. Its type species, B. variolaris, was named by Alexandre Brongniart in 1822, and is found in Dudley, England,.
Acastoides is an extinct genus of trilobite that lived during the Silurian and Devonian. It has been found in Bolivia, France, Morocco, Poland, Turkey and the United Kingdom.
Acernaspis is an extinct genus of trilobite that is known from the Silurian. It contains two species, A. elliptifrons, and A. salmoensis. It is sometimes found preserved in burrows of various forms, sometimes in association with multiple moults, suggesting that it used tunnels as refuges whilst in its vulnerable moulting stage.
Aegrotocatellus is a genus of trilobite in the order Phacopida, which existed in what is now Nunavut, Canada. It was named by Adrain and Edgecombe in 1995, and the type species is Aegrotocatellus jaggeri, a species named after British musician Mick Jagger.
Glyptambon is an extinct genus of Silurian trilobite in the order Phacopida. It is a member of the family Dalmanitidae and the subfamily Dalmanitinae, although it has been classified in the related Ordovician subfamily Mucronaspidinae. The type species G. verrucosus was once placed in Dalmania. Because this species was considered distinct from other Dalmania species, the new genus Glyptambon was erected for it in 1981. A second species, G. amsdeni, was named in 1991 from Tennessee and Illinois.
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.
Aulacopleura is a genus of proetid trilobite that lived from the Middle Ordovician to the Middle Devonian. The cephalon is semicircular or semielliptical, with border and preglabellar field. The glabella is short, with or without defined eye ridges connecting it with eyes of variable size. Spines at the rear outer corners of the cephalon are present, typically reaching back to the 2nd to 4th thorax segment. The 'palate' is not connected to the dorsal shield of the cephalon. The cephalon is pitted, or has small tubercles. The thorax has up to 22 segments. The pleural ends are usually rounded. The pygidium is small (micropygous), with an even margin.
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.
Mackenziurus is a genus of trilobites from the Silurian containing several species, including four named after members of the American punk band the Ramones.
Hedstroemia is a genus of trilobites in the order Proetida known from the Silurian period of Europe, Asia, and North America.
Odontopleura is a genus of spinose odontopleurid trilobite in the family Odontopleuridae, and is the type genus of that family and of Odontopleurida. The various species are found in Upper Ordovician to Middle Devonian marine strata throughout the world. The best studied fossils are of the type species, O. ovata, from the Wenlock-aged Liteň Formation in Loděnice, in Bohemia, Czech Republic, and, southeastern Gotland, of Sweden.
The Catavi Formation is a Pridoli to Emsian geologic formation of northern and central Bolivia. The formation comprises a 456 m (1,496 ft) thick succession of fine-grained, olive to brown sandstones and siltstones, shales and black limestones deposited in a shallow to deep marine environment.
