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The Ordovician–Silurian extinction events may have been caused by an ice age that occurred at the end of the Ordovician Period, due to the expansion of the first terrestrial plants, [54] as the end of the Late Ordovician was one of the coldest times in the last 600 million years of Earth's history.
The Late Ordovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician-Silurian extinction, is the first of the "big five" major mass extinction events in Earth's history, occurring roughly 445 million years ago (Ma). [1]
The Rugosa or rugose corals are an extinct order of solitary and colonial corals that were abundant in Middle Ordovician to Late Permian seas. [ 3 ] Solitary rugosans (e.g., Caninia , Lophophyllidium , Neozaphrentis , Streptelasma ) are often referred to as horn corals because of a unique horn-shaped chamber with a wrinkled, or rugose , wall.
The Ordovician period contained many marine animals. These animals can be found fossilized in the layers of the Cincinnati Arch. The types of animals that appear in these formations are: bryozoans, gastropods, cephalopods, horn corals, brachiopods, crinoids, and trilobites. [3]
The Early Ordovician is the first epoch of the Ordovician period, corresponding to the Lower Ordovician series of the Ordovician system. It began after the Age 10 of the Furongian epoch of the Cambrian and lasted from 486.85 to 471.3 million years ago, until the Dapingian age of the Middle Ordovician.
The creature lived on the ocean floor during the Ordovician Period (485 million to 444 million years ago) at a time when life had only a tentative foothold on land.
Until recently, scientists thought arthropods flourished during the Cambrian Period (538 million to 485 million years ago), which came before the period in which the specimen found by Parry's team ...
Geologists can divide the rocks of the Ordovician and Silurian periods into graptolite biozones; these are generally less than one million years in duration. A worldwide ice age at the end of the Ordovician eliminated most graptolites except the neograptines.