Bryozoa are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about 0.5 millimetres long, they have a special feeding structure called a lophophore, a "crown" of tentacles used for filter feeding. Most marine bryozoans live in tropical waters, but a few are found in oceanic trenches and polar waters. The bryozoans are classified as the marine bryozoans (Stenolaemata), freshwater bryozoans (Phylactolaemata), and mostly-marine bryozoans (Gymnolaemata), a few members of which prefer brackish water. 5,869 living species are known. One genus is solitary; all the rest are colonial.
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 (Mya) to the start of the Silurian Period 443.8 Mya.
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.
Polyteichus is a genus of bryozoans of the order Trepostomata. They are spherical, semi-spherical or disc shaped, with 3 or 4 radiating lobes, being 2–5 cm in diameter. The zooecia are shaped as wide prisms.
Favositella is an extinct genus of bryozoans from the Ordovician, Silurian and Devonian periods.
Chasmatopora is an extinct genus of bryozoans which existed in what is now Mongolia, China, Estonia, Russia, Poland, Argentina, the United States and Canada. It was described by Alcide d'Orbigny in 1849, and the type species is Chasmatopora tenella, which was originally described as a species of Retepora by Eichwald in 1842.
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.
Cystoporata, also known as Cystoporida or cystoporates, are an extinct order of Paleozoic bryozoans in the class Stenolaemata. Their fossils are found from Ordovician to Triassic strata.
Crepipora is an extinct genus of marine bryozoans belonging to the Ceramoporidae family. There are currently 18 collections from Belarus, Sweden, Canada, France and the United States. It was first assigned to Cystoporata by Sepkoski in 2002. The fossil range is from the Middle Ordovician to the Upper Ordovician.
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 Kimmswick Limestone is an Ordovician geologic formation in Arkansas, Illinois and Missouri. Fossils occurring in the Kimmswick include corals, bryozoans, brachiopods, conodonts, trilobites, crinoids and mollusks.
The Montoya Group is a group of geologic formations in westernmost Texas and southern New Mexico. It preserves fossils dating back to the late Ordovician period.
Monticulipora is an extinct genus of Ordovician bryozoans belonging to the family Monticuliporidae. It was first named in 1849, and its description was published the following year by French paleontologist Alcide M. d'Orbigny, making it one of the earliest bryozoans to be recognized in science. It is still one of the most widespread fossil bryozoan genera. Though colonies that grow in masses made of multiple layers are characteristic of the genus, its colonies have varying shapes, able to be encrusting, branching, massive, or frond-like, and are covered in monticules (bumps). Most Monticulipora species have distinctively granular walls, and Monticulipora and can be distinguished from Homotrypa by the presence of axial diaphragms.
Homotrypa is an extinct genus of bryozoans from the Ordovician and Silurian periods, known from fossils found in the United States. Its colonies are branch-like and have small monticules made of groups of three or four larger zooecia slightly protruding out from the main surface of the colony.In cross section, the zooecia are erect in axis and gently curve toward the surface of the colony.
Mesotrypa is a genus of bryozoans known from the Ordovician period, first described in 1893. Its colonies consist of low masses, wider than they are thick, made of superimposed layers, with small monticules on the surface of the colony.
Eridotrypa is an extinct genus of bryozoans of the family Aisenvergiidae, consistently forming colonies made of thin branches. Diaphragms are very common in colonies. Distinctively, in the exozone there are serrated dark borders separating the autozooecia.
Dianulites is an extinct genus of bryozoans from the early Ordovician period, belonging to the family Dianulitidae. Its colonies can be turbinate, horn-shaped, conical, or massive and hemispherical. Individual zooecia take the form of long, thin-walled polygonal tubes. It lacks styles (acanthopores), which helps differentiate it from similar genus Nicholsonella.
Rhombotrypa is an extinct trepostome bryozoan genus from the Ordovician Period, first described in 1866 by Carl Ludwig Rominger. Rhombotrypa quadrata is one of the few trepostome bryozoans known from the Cincinnatian that can be recognized externally, without analyzing the internal structure of the fossils.
Prasopora is an extinct genus of bryozoan belonging to the family Monticuliporidae, known from the Middle Ordovician. Its colonies were disc-shaped or hemispherical, flat on bottom and convex on top, and had very abundant mesopores; in the case of the species P. insularis its zooecia were isolated from each other by the numerous mesopores surrounding them. It is very similar to the genus Monticulipora, and some bryozoan species have been assigned to both genera at different points in their study, but it is mostly distinguished by having more mesozooecia, rounder autozooecial apertures, relatively few acanthostyles and diaphragms and cystiphragms equally distributed in the autozooecia.
Crassalina is an extinct genus of cystoporate bryozoan of the family Anolotichiidae, known from the Ordovician period. It had an encrusting growth habit or, in the case of C. fungiforme, formed cup-shaped colonies. Its colonies possessed a vesicular skeleton and monticules. Its cyst-like interzooecial spaces are a distinguishing feature.
