Permian

noun

Final period (290 to 248 million years ago) of the Palaeozoic era, which is named after the central Russian province of Perm. The period is often noted for the widespread continental conditions that prevailed in the northern hemisphere and for the extensive nature of the southern hemisphere glaciation. Many groups of animals and plants, including the rugose corals (Rugosa), trilobites (Trilobita), and blastoid echinoderms (Blastozoa), vanished at the end of the Permian, in a mass extinction that was one of the great crises in the history of life. The period is divided into seven ages: the Asselian, Sakmarian, Artinskian, and Kungurian Ages in the Early Permian Epoch (290 to 256.1 million years ago); and the Ufimian, Kazanian, and Tatarian Ages in the Late Permian Epoch (256.1 to 248 million years ago).