Trilobites

Next, I shall discuss the Trilobite. The Trilobite was a creature that lived from the Early Cambrian to the Late Permian Period. Trilobite means “three lobes.” The reason for this is not due to 3 body segments, but instead due to an axial lobe and left and right pleural lobes. “Pleural” means side or rib, not a grammatical number which dictates how nouns change if there is more than one of that noun. Some trilobites lived on the ocean floor and were predators, scavengers, or filter feeders. Others lived out in the open ocean and fed on plankton. Trilobite is not as specific a grouping as the Pterygotus, because “Pterygotus” identifies 4 known species while “Trilobite” identifies over 20,000. Trilobites, like other arthropods, have exoskeletons made out of chitin. They also, like other arthropods, are divided into segments. Trilobites are divided into the cephalon, a segmented thorax, and a pygidium. The Pygidium is a tail peace. I’m guessing you know what a thorax is, and as for the cephalon, try and use the prefix to find out. The Cephalon contains the eyes, antennae, mouth, and a few pairs of legs. The Thorax contains legs and gills under each segment. The segments also allow a trilobite to roll into a protective ball. The Pygidium is ade up of fused segments, unlike the thorax, where you can see more divisions. The Pygidium varies in size among trilobite species. The four general sizes are micropygous, much smaller than the cephalon, subisopygous, smaller than isopygous, but still similar size, isopygous, the same size as the cephalon, and macropygous, larger than the cephalon. The Trilobites were one of the first animals with compound eyes, although there are some that are eyeless. The two major types of eyes trilobites have. One is the holochroal, compound eyes with no division between individual lenses, somewhat like the eyes of most insects you see. The other is the schizochroal, which has circular segments instead of hexagonal and are divided by sclera, cuticular exoskeleton material, which is somewhat lower than the lenses. As you may have guessed, I like trilobites, but I am not the expert about information relating to them. Most of the information here was from http://www.trilobites.info/trilobite.htm. If you find any incorrect information, please comment on it. For those who play Pokemon, Kabuto is like a trilobite, but with a smoother shell, fewer legs, and no place where you can identify segmentation. Apparently, Kabutops is supposed to resemble a eurypterid, but I only partially see the resemblance. You can look at the Pterygotus picture yourself and decide if it looks like a Kabutops. Now, my discussion of Paleozoic life is over. My favorite animals from the prehistoric Cenozoic Era will be discussed next. One Dinosaur will be discussed, but not yet.

Pterygotus

This blog is named after something rather obscure, but I like it. The Pterygotus is a eurypterid, which comes from the Greek words eury, meaning "wide," and pteron, meaning "wing." The Eurypterids are also known as sea scorpions and are predators. "Pterygotus" is actually a genus currently encompassing three other euryptids, but usually refers to Pterygotus Anglicus. It is the second largest eurypterid, but Jaekelopterus is larger. It can be up to 7 feet long. It looks like a lobster with large compound eyes and also had some smaller eyes. It has pincers, 4 small legs on each side, and another pair of legs that act like flippers. I have chosen to place a picture of it at the top of the blog. Luckily for people who are afraid of 7 foot arthropods, it , as well as all other eurypterids, is extinct and lived during the Silurian Era, while other eurypterids ranged from the Ordovician to the Permain period. They used to live in shallow waters, like crustaceans. Some Eurypterids lived in salt water; these tended to be the earlier ones, but eventually went to brackish and fresh water. Brackish water is water that is in between fresh and salt water. This is estimated to have happened during the Pennsylvanian era, so I'm guessing that Pterygotus lived in salt water. For the convenience of people who do not have knowledge of the different time periods which ancient creatures are said to have lived in, I will list these and say what time they occurred. The first period is the Cambrian, 542 - 488.3 mya, which is when an "explosion" of sea life happened, I say the sea because sea life was mostly the only life that existed in this time. Next came Ordovician, 488.3 - 443.7 mya, and then Silurian, 443.7 - 416 mya, sea life was still the most important at this time, but many of the Cambrian species went extinct during this time. The Devonian Era, 416 - 359.2 mya, was when life started forming on the land. The Carboniferous Era, 359.2 - 299 mya, which was also divided into the Mississippian Era and the Pennsylvanian Era, came next. Then in the Permian Period, 299 - 251 mya, brought about the extinction of more life. This was the Paleozoic Era. The Mesozoic had Dinosaurs in it, and then comes the Cenozoic Era. I will discuss some things in the Cenozoic Era, but I will not divide this further. In case you are wondering, this blog will not be entirely about prehistoric creatures, but it will be a topic for a while.