| Coronocephalus | |
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| Coronocephalus gauluoensis | |
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| Genus: | †Coronocephalus Grabau, 1924 |
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Several, including:
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Coronocephalus is an extinct genus of trilobites in the Phacopid family Encrinuridae. Species are from the Silurian of Australia and Japan, and from the Silurian and Ordovician of China. [1] [2]
The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.
Trilobites are a group of extinct marine arachnomorph 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 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 300 million years.
The Maotianshan Shales are a series of Early Cambrian deposits in the Chiungchussu Formation, famous for their Konservat Lagerstätten, deposits known for the exceptional preservation of fossilized organisms or traces. The Maotianshan Shales form one of some forty Cambrian fossil locations worldwide exhibiting exquisite preservation of rarely preserved, non-mineralized soft tissue, comparable to the fossils of the Burgess Shale. They take their name from Maotianshan Hill in Chengjiang County, Yunnan Province, China.
Marrella is an extinct genus of arthropod known from the middle Cambrian Burgess Shale of British Columbia. It is the most common animal represented in the Burgess Shale.
The Ordovician–Silurian extinction events, also known as the Late Ordovician mass extinction (LOME), are collectively the second-largest of the five major extinction events in Earth's history in terms of percentage of genera that became extinct. Extinction was global during this period, eliminating 49–60% of marine genera and nearly 85% of marine species. Only the Permian-Triassic mass extinction exceeds the LOME in total biodiversity loss. The extinction event abruptly affected all major taxonomic groups and caused the disappearance of one third of all brachiopod and bryozoan families, as well as numerous groups of conodonts, trilobites, echinoderms, corals, bivalves, and graptolites. This extinction was the first of the "big five" Phanerozoic mass extinction events and was the first to significantly affect animal-based communities. However, the LOME did not produce major changes to ecosystem structures compared to other mass extinctions, nor did it lead to any particular morphological innovations. Diversity gradually recovered to pre-extinction levels over the first 5 million years of the Silurian period.
In the geological timescale, the Llandovery epoch occurred at the beginning of the Silurian period. The Llandoverian epoch follows the massive Ordovician-Silurian extinction events, which led to a large decrease in biodiversity and an opening up of ecosystems.
Calymene is a genus of trilobites in the order Phacopida 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.
Calymene blumenbachii, sometimes erroneously spelled blumenbachi, is a species of trilobite discovered in the limestone quarries of the Wren's Nest in Dudley, England. Nicknamed the Dudley Bug or Dudley Locust by 18th-century quarrymen it became a symbol of the town and featured on the Dudley County Borough Council coat-of-arms. Calymene blumenbachii is commonly found in Silurian rocks and is thought to have lived in the shallow waters of the Silurian, in low-energy reefs. This particular species of Calymene is unique to the Wenlock series in England, and comes from the Wenlock Limestone Formation in Much Wenlock and the Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge, and the rock here is dark grey as opposed to yellowish or whitish as it appears on other parts of the Edge, just a few miles away, in Church Stretton and elsewhere. This suggests local changes in the environment in which the rock was deposited.
Yunnanocephalus is a genus of ptychopariid trilobite. It lived during the late Atdabanian and Botomian stages, in what are currently Antarctica, Australia and China. It was a "moderately common" member of the Chengjiang Fauna. Yunnanocephalus is the only genus currently assigned to the Yunnanocephalidae family.
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.
Pagetia is a genus of very small, agnostid trilobites, assigned to the family Eodiscidae, and that had a global distribution during the Middle Cambrian. The genus contains 55 currently recognized species, each with a limited spatial and temporal distribution.
Selkirkia is a genus of predatory, tubicolous priapulid worms known from the Middle Cambrian Burgess Shale, Ogygopsis Shale and Puncoviscana Formation. 142 specimens of Selkirkia are known from the Greater Phyllopod bed, where they comprise 0.27% of the community. In the Burgess Shale, 20% of the tapering, organic-walled tubes are preserved with the worm inside them, whereas the other 80% are empty. Whilst alive, the tubes were probably vertical, whereas trilobite-occupied tubes are horizontal.
The Mount Cap Formation is a geologic formation exposed in the Mackenzie Mountains, northern Canada. It was deposited in a shallow shelf setting in the late Early Cambrian, and contains an array of Burgess Shale-type microfossils that have been recovered by acid maceration.
Bradoriids are small marine arthropods with a bivalved carapace, and were globally distributed, forming a significant portion of the Cambrian and early Ordovician soft-bodied communities.
Paleontology in Wisconsin refers to paleontological research occurring within or conducted by people from the U.S. state of Wisconsin. The state has fossils from the Precambrian, much of the Paleozoic, and the later part of the Cenozoic. Most of the Paleozoic rocks are marine in origin. Because of the thick blanket of Pleistocene glacial sediment that covers the rock strata in most of the state, Wisconsin’s fossil record is relatively sparse. In spite of this, certain Wisconsin paleontological occurrences provide exceptional insights concerning the history and diversity of life on Earth.
This list of fossil arthropods described in 2018 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that were described during the year 2018, as well as other significant discoveries and events related to arthropod paleontology that are scheduled to occur in the year 2018.
The Artiopoda is a grouping of extinct arthropods that includes trilobites and their close relatives. It was erected by Hou and Bergström in 1997 to encompass a wide diversity of arthropods that would traditionally have been assigned to the Trilobitomorpha. Hou and Bergström used the name Lamellipedia as a superclass to replace Trilobitomorpha that was originally erected at the subphylum level, which they considered inappropriate.
This list of fossil arthropods described in 2019 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that are scheduled to be described during the year 2019, as well as other significant discoveries and events related to arthropod paleontology that are scheduled to occur in the year 2019.
Prosomapoda is a clade of euchelicerates including the groups Xiphosura and Planaterga, as well as several basal synziphosurid genera. The clade is defined by the lack of exopods of prosomal appendage II-V in the adult instar, where in contrast the exopods of appendage II-V are well-developed in the non-prosomapod euchelicerates Offacolus and Dibasterium.
The Waukesha Biota refers to the biotic assemblage of the Konservat-Lagerstätte of Early Silurian age within the Brandon Bridge Formation in Waukesha County and Franklin, Milwaukee County, Wisconsin. It is known for the exceptional preservation of its diverse, soft-bodied and lightly skeletonized taxa, including many major taxa found nowhere else in strata of similar age.
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