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.
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.
Hederellids are extinct colonial animals with calcitic tubular branching exoskeletons. They range from the Silurian to the Permian and were most common in the Devonian period. They are more properly known as "hederelloids" because they were originally defined as a suborder by Bassler (1939), who described about 130 species. Although they have traditionally been considered bryozoans, they are clearly not because of their branching patterns, lack of an astogenetic gradient, skeletal microstructure, and wide range in tube diameters. Work continues on assessing the true affinities of hederelloids, but they appear to be most closely related to phoronids and other lophophorates.
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 radar.
The Phragmoceratidae is a family of extinct nautiloid cephalopods from the Order Discosorida that lived during the latter part of the Silurian.
Lunostoma is an extinct genus of bryozoans which existed during the middle Devonian of what is now Germany, precisely from the Gerolstein syncline. It was described by Andrej Ernst, Paul D. Taylor, Jan Bohatý and Patrick N. Wyse Jackson in 2012, and the type species is L. pulchra.
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 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.
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.
Fenestrata is an extinct order of bryozoan, dating from the Upper Arenig. Most fenestrate bryozoans formed net-like colonies that water currents flowed through, with autozooecial apertures only on the side of the colony facing into the current.This colony structure was vulnerable to predators, so some fenestrate bryozoans produced skeletal superstructures, likely to strengthen or protect the colony, and others had protective spines surrounding their autozooecial apertures.
The Maquoketa Formation is a geologic formation in Illinois, Indiana. Iowa, Kansas, Minnesota, Missouri, and Wisconsin. It preserves mollusk, coral, brachiopod and graptolite fossils dating back to the Darriwilian to Hirnantian stages of the Ordovician period.
Olev Vinn is Estonian paleobiologist and paleontologist.
Septopora is an extinct genus of bryozoan belonging to the order Fenestrida. It has been found in Pennsylvanian to Permian beds in North America, South America, Australia, and southwest and east Asia.
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.
Diploclema is an extinct genus of bryozoan belonging to the monotypic family Dipoclemidae, found from the Middle Ordovician to the Middle Silurian. It has pear-shaped autozooecia which grow in a biradial pattern, and its colonies have a dichotomously branching shape. Its laminated exterior wall possesses a prismatic structure, which is unique among the cyclostome bryozoans.
Ptilodictya is an extinct genus of bryozoan of the family Ptilodictyidae. It formed bifoliate branched colonies, with branches ranging from under 1 to 3 mm wide. Colonies' autozooecia are rectangular and autozooecial apertures are in the shape of rounded rectangles.
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.
Lichenalia is an extinct genus of cystoporate bryozoan of the family Rhinoporidae, known from the Upper Ordovician to the Middle Silurian. Its colonies could form hollow branched or tube-shaped colonies or have an encrusting growth habit. It possessed prominent lunaria and a vesicular skeleton. As in other members of Rhinoporidae, the vesicular skeleton contained tunnels that appeared like ridges on the surface of the colony. Their purpose is unknown, but they may have been used as brooding chambers.
Dybowskites is an extinct genus of bryozoan of the family Ralfimartitidae, found in the Ordovician and Silurian periods. It forms branching, frond-like, or sometimes segmented colonies. In cross-sections of the colonies, the tubular autozooecia are seen growing alongside the branch axis and then bending abruptly to reach the colony surface at a perpendicular angle. There are many mesozooecia and large acanthostyles that protrude from the colony surface.
