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. At least two genera are solitary ; 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 (Ma) 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.
Hallopora is an extinct genus of bryozoans of the family Halloporidae, first identified from the Lower Silurian period. They can be found in Ohio, Indiana, and Kentucky of the Midwestern United States, commonly in the Ordovician Kope Formation.
Trepostomatida is an extinct order of bryozoans in the class Stenolaemata. Trepostome bryozoans possessed mineralized calcitic skeletons and are frequently fossilized; some of the largest known fossilized bryozoan colonies are branching trepostomes and massive dome-shaped trepostomes. Trepostomes did not have many specialized zooecia beyond ordinary feeding autozooecia. The two main known heteromorphs are exilazooecia and mesozooecia, which had the purpose of maintaining regular spacing between autozooecia.
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.
Helen Margaret Duncan was a geologist and paleontologist with the United States Geological Survey from 1945 to 1971, where she worked in the Paleontology and Stratigraphy Branch. Duncan was considered one of the strongest women in the Cincinnati geology department; her contributions to the Lipalian Research Foundation and the Pick and Hammer shows were additional work of her time. Duncan paved the path for many geology scholars to follow with her discoveries on fossil records and her studies in paleontology and stratigraphy.
Paleontology in Kentucky refers to paleontological research occurring within or conducted by people from the U.S. state of Kentucky.
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.
Paleontology in Missouri refers to paleontological research occurring within or conducted by people from the U.S. state of Missouri. The geologic column of Missouri spans all of geologic history from the Precambrian to present with the exception of the Permian, Triassic, and Jurassic. Brachiopods are probably the most common fossils in Missouri.
Paleontology in Minnesota refers to paleontological research occurring within or conducted by people from the U.S. state of Minnesota. The geologic record of Minnesota spans from Precambrian to recent with the exceptions of major gaps including the Silurian period, the interval from the Middle to Upper Devonian to the Cretaceous, and the Cenozoic. During the Precambrian, Minnesota was covered by an ocean where local bacteria ended up forming banded iron formations and stromatolites. During the early part of the Paleozoic era southern Minnesota was covered by a shallow tropical sea that would come to be home to creatures like brachiopods, bryozoans, massive cephalopods, corals, crinoids, graptolites, and trilobites. The sea withdrew from the state during the Silurian, but returned during the Devonian. However, the rest of the Paleozoic is missing from the local rock record. The Triassic is also missing from the local rock record and Jurassic deposits, while present, lack fossils. Another sea entered the state during the Cretaceous period, this one inhabited by creatures like ammonites and sawfish. Duckbilled dinosaurs roamed the land. The Paleogene and Neogene periods of the ensuing Cenozoic era are also missing from the local rock record, but during the Ice Age evidence points to glacial activity in the state. Woolly mammoths, mastodons, and musk oxen inhabited Minnesota at the time. Local Native Americans interpreted such remains as the bones of the water monster Unktehi. They also told myths about thunder birds that may have been based on Ice Age bird fossils. By the early 19th century, the state's fossil had already attracted the attention of formally trained scientists. Early research included the Cretaceous plant discoveries made by Leo Lesquereux.
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.
Ceramopora is an extinct genus of bryozoan of the family Ceramoporidae. It is one of the earliest genera of bryozoans. Its colonies were thin and discoid, with large autozooecia, abundant communication pores, lunaria, and monticules with depressions in their centers. It had no acanthostyles or diaphragms, distinguishing it from Acanthoceramoporella.
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.
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.
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.
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.
Revalotrypa is an extinct genus of bryozoan of the family Revalotrypidae that lived during the late Ordovician period. It was initially placed within the order Trepostomatida, but later moved to Cystoporida, a classification supported by the discovery of the very similar genus Lynnopora, which possesses lunaria in its autozooidal apertures, a quality distinctive of Cystoporida.
Crassaluna 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.
Lichenalia is an extinct genus of cystoporate bryozoan belonging to the family Rhinoporidae. It is known from the Upper Ordovician to the Middle Silurian periods, which spanned from approximately 460 to 430 million years ago. The genus had a cosmopolitan distribution, with fossil specimens found in various regions of the world, including North America, Europe, and Asia.
