| Orectodictya Temporal range: | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Bryozoa |
| Class: | Stenolaemata |
| Order: | † Cryptostomida |
| Family: | † Rhinidictyidae |
| Genus: | † Orectodictya Karklins, 1983 |
| Species: | †O. pansa |
| Binomial name | |
| †Orectodictya pansa Karklins, 1983 | |
Orectodictya is an extinct genus of ptilodictyoid bryozoans known from Ordovician fossils found in the U.S. state of Kentucky. [1] It is monotypic, containing the single species Orectodictya pansa. [2]
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Ma) to the start of the Silurian Period 443.8 Mya.
Acritarchs are organic microfossils, known from approximately 1800 million years ago to the present. The classification is a catch all term used to refer to any organic microfossils that cannot be assigned to other groups. Their diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion.
Stenolaemata are a class of exclusively marine bryozoans. Stenolaemates originated and diversified in the Ordovician, and more than 600 species are still alive today. All extant (living) species are in the order Cyclostomatida, the third-largest order of living bryozoans.
The Tremadocian is the lowest stage of Ordovician. Together with the later Floian Stage it forms the Lower Ordovician Epoch. The Tremadocian lasted from 485.4 to 477.7 million years ago. The base of the Tremadocian is defined as the first appearance of the conodont species Iapetognathus fluctivagus at the Global Boundary Stratotype Section and Point (GSSP) section on Newfoundland.
Cameroceras is an extinct genus of endocerid cephalopod which lived in equatorial oceans during the entire Ordovician period. Like other endocerids, it was an orthocone, meaning that its shell was fairly straight and pointed. It was particularly abundant and widespread in the Late Ordovician, inhabiting the shallow tropical seas in and around Laurentia, Baltica and Siberia.
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.
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.
Gravicalymene Shirley, 1936, is a genus of trilobites belonging to the order Phacopida, suborder Calymenina and family Calymenidae. Species included in this genus have previously been allocated to Calymene Brongniart 1822,Flexicalymene Shirley, 1936. and Sthenarocalymene Siveter 1977.
Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor. A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone sequences and distinguished from later-lithified sediments by evidence of exposure to normal marine waters. This evidence can consist of encrusting marine organisms, borings of organisms produced through bioerosion, early marine calcite cements, or extensive surfaces mineralized by iron oxides or calcium phosphates. Modern hardgrounds are usually detected by sounding in shallow water or through remote sensing techniques like side-scan sonar.
Calyptaulax is a genus of trilobites in the order Phacopida that existed during the middle and upper Ordovician in what is now the U.S. states of New York, Oklahoma, Illinois, Missouri, Virginia, Vermont, Nevada, Iowa, Wisconsin, Kentucky, and Iowa, as well as the Canadian provinces of Ontario, Newfoundland and Labrador, Quebec, and the territory of Nunavut. Other countries Calyptaulax fossils are known from include Ireland, Norway, Russia, and the United Kingdom.
The Cincinnati Arch is a broad structural uplift between the Illinois Basin to the west, the Michigan Basin to the northwest and the Appalachian Basin and Black Warrior Basin to the east and southeast. It existed as a positive topographic area during Late Ordovician through the Devonian Period which stretched from northern Alabama northeastward to the southeastern tip of Ontario. Fossils from the Ordovician Period are commonplace in the geologic formations which make up the Cincinnati Arch, and are commonly studied along man made roadcuts. The Nashville Dome of Tennessee and the Jessamine Dome or Lexington Dome of central Kentucky make up the central portion of the Arch. In the northern part, north of Cincinnati, Ohio, the Cincinnati Arch branches to form the Findlay and Kankakee arches. The Findlay plunges under Ontario and reappears as the Algonquin Arch further north.
Cartersoceras is a genus of nautiloid cephalopods placed in the Orthocerid family Baltoceratidae, established by Rousseau Flower (1964), for species formally included in part in Murrayoceras, and in part in "Sacotoceras". This group is typical of Murrayoceras in all features except that the siphuncle segments are convex in outline. It is known from the Middle Ordovician of the eastern United States.
Stigmatella is an extinct genus of bryozoans in the family Heterotrypidae. It is known from the Ordovician period and found in the U.S. states of Ohio, Kentucky and Indiana. Its colonies can form branches, lobes, or masses made from new layers encrusting upon older ones. In Kentucky, fossil remains of species Stigmatella personata that lived in underwater caves have been found, growing 'upside-down' on the cave ceiling.
Paleontology in Kentucky refers to paleontological research occurring within or conducted by people from the U.S. state of Kentucky.
Paleontology in Virginia refers to paleontological research occurring within or conducted by people from the U.S. state of Virginia. The geologic column in Virginia spans from the Cambrian to the Quaternary. During the early part of the Paleozoic, Virginia was covered by a warm shallow sea. This sea would come to be inhabited by creatures like brachiopods, bryozoans, corals, and nautiloids. The state was briefly out of the sea during the Ordovician, but by the Silurian it was once again submerged. During this second period of inundation the state was home to brachiopods, trilobites and entire reef systems. During the mid-to-late Carboniferous the state gradually became a swampy environment.
Paleontology in Tennessee refers to paleontological research occurring within or conducted by people from the U.S. state of Tennessee. During the early part of the Paleozoic era, Tennessee was covered by a warm, shallow sea. This sea was home to brachiopods, bryozoans, cephalopods, corals, and trilobites. Tennessee is one of the best sources of Early Devonian fossils in North America. During the mid-to-late Carboniferous, the state became a swampy environment, home to a rich variety of plants including ferns and scale trees. A gap in the local rock record spans from the Permian through the Jurassic. During the Cretaceous, the western part of the state was submerged by seawater. The local waters were home to more fossil gastropods than are known from anywhere else in the world. Mosasaurs and sea turtles also inhabited these waters. On land the state was home to dinosaurs. Western Tennessee was still under the sea during the early part of the Cenozoic. Terrestrial portions of the state were swampy. Climate cooled until the Ice Age, when the state was home to Camelops, horses, mammoths, mastodons, and giant ground sloths. The local Yuchi people told myths of giant lizard monsters that may have been inspired by fossils either local or encountered elsewhere. In 1920, after local fossils became a subject of formal scientific study, a significant discovery of a variety of Pleistocene creatures was made near Nashville. The Cretaceous bivalve Pterotrigonia thoracica is the Tennessee state fossil.
The Lexington Limestone is a prominent geologic formation that constitutes a large part of the late Ordovician bedrock of the inner Bluegrass region in Kentucky. Named after the city of Lexington, the geologic formation has heavily influenced both the surface topography and economy of the region.
The Black River Group is a geologic group that covers three sedimentary basins in the Eastern and Midwestern United States. These include the Appalachian Basin, Illinois Basin and the Michigan Basin. It dates back to the Late Ordovician period. It is roughly equivalent to the Platteville Group in Illinois. In Kentucky and Tennessee it is also known as the High Bridge Group. In areas where this Geologic Unit thins it is also called the Black River Formation (undifferentiated). One example of this is over the Cincinnati Arch & Findley Arch. Large parts of the Black River have been dolomized (where the parent limestone CaCO3 has been turned into dolomite CaMg(CO3)2.) This happed when there was interaction of hot saline brine and the limestone. This created hydrothermal dolomites that in some areas serve as petroleum reservoirs.
Diploporita is an extinct class of blastozoan that ranged from the Ordovician to the Devonian. These echinoderms are identified by a specialized respiratory structure, called diplopores. Diplopores are a double pore system that sit within a depression on a single thecal (body) plate; each plate can contain numerous diplopore pairs.
Acanthoceramoporella is an extinct genus of cystoporate bryozoans from the Ordovician period.
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