Later in the period it moved northwards and began to twist clockwise, though it was not near its modern location. Sea levels were exceptionally high during the Devonian, giving a widespread relatively warm and equable climate for most of the Period. The southern continents of today were united into the supercontinent of Gondwana during the Devonian approximately along the lines of their present-day continental shelf boundaries. Plants started to show up in the Age of Fishes. They (alongside red algae) were responsible for creating reefs in the waters. This class of cephalopod molluscs would dominate the marine fauna until the beginning of the Mesozoic Era. Also, the first possible fossils of insects appeared around 416 Mya, in the Early Devonian. Such methods focus on the distribution of evaporites, shelf carbonates, and corals because present-day deposits of these types have specific, well-known climatic constraints. This period started about 419 million years ago and ended 358.9 million years ago. The paleoequator (the site of the Equator at a point in the geological past) passed through North America and through China, which was at that time a separate landmass. Placoderms and the first groups of jawed fish began to appear in the Middle Devonian. Causes of the extinctions include global cooling, including glaciations in the south polar area of Gondwana, and anoxia (oxygen loss) in the oceans. In 1947 oil was discovered in an Upper Devonian reef at Leduc, Alta., The Devonian Period is the fourth period of the Paleozoic Era. The name of the Devonian Period is derived from the county of Devon, Eng. In these near-deserts, the Old Red Sandstone sedimentary beds formed, made red by the oxidised iron (hematite) characteristic of drought conditions. The former killed off coral reefs, jawless fish, and trilobites, while the latter caused early ammonites and placoderms to die off. [57] Together, these are considered one of the "Big Five" mass extinctions in Earth's history. Stromatoporoids, as well as corals, increased greatly during the Devonian. shows some of the beautiful patterns cephalopod fossils are known for. The Kellwasser and Hangeberg events were the two longest episodes of the mass extinction. The fast appearance of so many plant groups at the end of the Devonian Period has been termed the Devonian Explosion. The diversification also brought about an increase in the variety of arthropods that existed. Details of the anatomy of this early plant are shown in the macrophotos: image showing spines (right edge of stem) and central tracheal element (center of stem, upper half). The shallow, warm, oxygen-depleted waters of Devonian inland lakes, surrounded by primitive plants, provided the environment necessary for certain early fish to develop such essential characteristics as well developed lungs, and the ability to crawl out of the water and onto the land for short periods of time. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. Live Science is part of Future US Inc, an international media group and leading digital publisher. Answer to: When did the Devonian period begin? 443.8 (+/- 1.5) million years ago Silurian/Began Brachiopods (ToL: Brachiopoda Survival Rate Of Being Ejected From A Car, Articles W