The Devonian Period
The Devonian period occurred from 416 million to 358 million years ago. It was the fourth period of the Paleozoic Era and it was followed by the Silurian Period. The Devonian period is known as "The Age of the Fishes". This name came to be because of the diverse, abundant, and, in some cases, bizarre types of these creatures that swam Devonian seas (House). During most of the Devonian Period, North America, Greenland, and Europe were united into a single Northern Hemisphere landmass, a minor supercontinent called Laurussia or Euramerica. This huge landmass mostly occurred at the beginning of the Devonian Period.
During this period, the climate was pretty warm. In the Northern Hemisphere, the temperatures were similar…show more content… The average length of a Placoderm were up to 33 feet. Fish that resembled sharks and rays, Cartilaginous fish, were very common by the late Devonian. During the mid Devonian there were fossils that showed fish that had true bones, teeth, swim bladders and gills (Live Science). The most modern fish was called the Ray-Finned fish. The paired pelvic and pectoral fins were supported by several long thin bones powered by muscles largely within the trunk. Another group of fish that were pretty common around this time was Lobe-Finned fish and it was more common than the Ray-Finned fish, but a lot of the fish died. They had fleshy and pectoral and pelvic fins articulating to the shoulder or pelvis by a single bones and that was powered by muscles and the are also commonly known as the ancestors of all tetrapods. Some species were able to breathe air through spiracles in the…show more content… The earliest insect was known, Rhyniella praecusor, was a flightless hexapod with antennae and a segmented body. Fossil Rhyniella are between 412 million and 391 million years old. The earliest tetrapod is Tiktaalik rosae. This tetra pod was dated from the mid-Devonian and it is simiular to the lobe-finned fish and early amphibians. Tiktaalik was the most aquatic walking on the bottom of shallow estuaries. This creature had a fish-like pelvis, but its hind limbs were larger and stronger than the ones that where in the front. The head was one similuar to a crocodile, a movable neck, and nostrils for breathing
