One of the two is the group known as the Saurischians. Saurischia in greek means ‘Lizard Hip joint’ (Farke). The two groups were classified by british paleontologist Harry Seeley in 1888 It included two types of dinosaurs, Sauropods and Theropods. Examples of Saurischians include Brachiosaurus and Amargasaurus, both of which are sauropods or long necked herbivorous dinosaurs, and the Theropods or bipedal carnivorous dinosaurs like Allosaurus, T.rex and Velociraptor. The structure of the hip starts with the base, the Ilium on top, the pubis under the Ilium at a 50 degree angle and the Ischium, which connects to the Ilium and points backwards towards the tail. All the birds that are alive today are also included in the Saurischian group. The Sauropods were the largest land animals to ever walk the earth moving at a pace of around 4 to 6 miles per hour. They were all herbivores stripping leaves from trees and grazing on low-lying plants like ferns and horsetails (Baggaley). The Theropods were carnivorous dinosaur who came in many sizes from the 18 meter long Spinosaurus to the 13 inch long Anchiornis. The diets of the carnivores could vary between species. Examples are Other dinosaurs, carcasses, mostly those who were scavengers or for an easy meal, bugs/insects and …show more content…
This group makes up most of the dinosaur species in the world. Ornithischia in greek means ‘bird hip joint’. The class of ornithischia include Hadrosaurs, Pachycephalosaurs, Stegosaurs, Ankylosaurs and ceratopsians. The hips of ornithischians are very different from Saurischians. The structure of the hip includes the Ilium on top, the pubis across the bottom and the Ischium in the back connecting to both the Ilium and pubis pointing back towards the tail. All ornithischians to date are herbivorous dinosaurs usually being very big. The Hadrosaurs were quadrupedal dinosaurs, but sometimes moved on two feet usually for running. Most usually had some sort of head crest of display that allowed air from their nostrils to be blown out to make unique calls for each species. It is theorized the the hadrosaur Parasaurolophus made low trumpet-like sounds with its long crest. The pachycephalosaurs were bipedal dinosaurs with thick domes made out of bone on top of their heads. Some even had spikes and long horns near the dome (farke). It is thought that the dome could have been used like the rams today for disputes over mates. Another thought is that the domes were just used for display in mating and not for ramming. The Stegosaurs were large quadrupedal dinosaurs that had bony plates along their backs, usually having defencive spikes at the end of the tail. Some stegosaurs had spikes on their tail