The tectonic effects of this collision continued into the Devonian, producing a string of mountain ranges along the southeastern coast of the continent. At the terminus of the Devonian, Earth rapidly cooled into an icehouse, marking the beginning of the Late Palaeozoic Ice Age. [41], By the Devonian Period, life was well underway in its colonization of the land. n, d-, d-/ dih-VOH-nee-n, d-, deh-) is a geologic period and system of the Paleozoic, spanning 60.3 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya. Cartilaginous fish such as sharks and rays were common by the late Devonian. Paleomagnetic evidence, however, is not clear, and various positions for the exact placement of the paleoequator have been proposed. The recognition that such major paleogeographic differences existed was a great scientific advance, and it was soon confirmed when Sedgwick and Murchison visited Germany and again when Murchison discovered an intercalation of Devonian marine fossils and Old Red Sandstone fishes near St. Petersburg, Russia. Other minor oceans were the Paleo-Tethys Ocean and Rheic Ocean. They had streamlined bodies, multiple rows of sharp teeth, and keen senses, including a strong sense of smell. The first tetrapods appeared in the fossil record in the ensuing Famennian subdivision, the beginning and end of which are marked with extinction events. Rising fast: the first trees. By the end of the Devonian, progymnosperms such as Archaeopteris were the first successful trees. The great diversity of fish around at the time has led to the Devonian being given the name "The Age of Fish" in popular culture. The lunar cycle, about 301/2 days, was one day longer than it is now. Both effects resulted from indirect impacts of the new plant ecosystemsswamps and forests tied up carbon dioxide, while runoff into the seas provided carbon to be consumed by aerobic bacteria, depleting the oxygen needed by animals. They (alongside red algae) were responsible for creating reefs in the waters. Two major events during this time were the formation of a supercontinent and a mass extinction event that caused the disappearance of about 70% of marine life. Enter your email in the box below to get the most mind-blowing animal stories and videos delivered directly to your inbox every day. These early collisions preceded the formation of Pangaea in the Late Paleozoic. Early cartilaginous (Chondrichthyes) and bony fishes (Osteichthyes) also become diverse and played a large role within the Devonian seas. An extinction event at the end of the Devonian killed off at least 75% of all species on Earth, including many lineages of fish that once swam the oceans. Scientists have found little to no evidence of polar ice caps from the Devonian period. Explanation of map symbols. They were separated from the southern continent by an oceanic basin: the Paleo-Tethys. Sponges (ToL: Porifera