Dinosaur Paleontology Definitions you should remember Paleontologist Someone who studies any aspect of ancient organisms Fossils Remains of ancient life For dinosaurs we tend to think solely of these as bones Cladistics A method to organize physical characteristics of dinosaurs and discern re lationships Finite Element Model Used to find out the bite force of dinosaurs Encephalization Quotient A measure of brain size relative to body mass Endocasts Formed by sediments that filled the brain cavity during the fossilization process and became solidified From these we know the brain size of dinosaurs Oversplitting Naming more species than there really are First proper scientific named dinosaur was Scrotum humanum so named because thought to be dinosaur private parts now known to have been the end of a dinosaur s thigh bone First written accounts of dinosaurs come from china Mosasaurus sea monster Cuvier said things go extinct Concept of extinction was for the first time realized by a few europeans Richard Owen took stock of all the crazy giants being found in Europe and noted they were different than the reptiles living today giant have upright posture named them Dinosauria meaning Fearfully Giant Reptiles How Do we Learn More About Dinosaurs It is important to realize there is another category of fossils called Trace Fossils These are traces of creatures they are not physical remains of the animals tissues Includes Dino tracks eggs bite marks coprolites skin impressions etc Tracks Reveal aspects of posture walking and running speeds group behavior Be cause of tracks we know dinosaurs didn t drag their tails Skin Impressions Reveal aspects of thermoregulation and display features Gastroliths gizzard stones aid in digestion like our molars as well as stomach con tents Reveal capacities to further breakdown foods and what was eaten Eggs and nests Aspects of ovaries Bite marks Tell us who ate who Coprolites Tells us what they ate if they had strong digestive acids how much the dentition broke down items Where do we find dinosaurs Sedimentary rocks rivers deserts etc Very rarely find them in volcano rocks or metamorphic rocks Best place to find them are badlands Closest place to find dinosaurs is in Columbus Georgia Will not find dinosaurs in Flor ida What makes a dinosaur a dinosaur Dinosaurs have teeth in sockets like crocodiles and pterosaurs and are thus close rela tives Unique dinosaur feature 1 Three or more sacral vertebrae fused backbones in hip region Unique dinosaur feature 2 Hands with 3 main fingers Unique dinosaur feature 3 Perforate acetabulae i e the hole where the thighbone at tached goes all the way through the hip Dinosaur Renaissance Ostrom discovered Deinonychus an athletic animal Robbert Bakker said that all dinosaurs were athletic and more like living birds and mammals Outcome everyone started studying dinosaurs and jobs were created more money is spent on dinosaurs than ever before By the late 1800s there were two types of dinosaurs hips shaped like birds ornithischians hips shaped like lizards saursichians When did dinosaurs live Lived 238 million years until 65 5 million years ago How do we know these ages Look at radioactive isotopes in volcanic rocks Compare original amount to final amount to assess age For dinosaur age uranium 235 is best It is pure when volcano rocks cool Carbon dating is too short to be of our use for di nosaurs Life of dinosaurs on earth By the middle of the Cretaceous period flowering plants start showing up These plants regenerate quickly can survive grazing Who lived with the dinosaurs Keep in mind that dinosaurs were terrestrial We have no credible evidence that they were amphibious or aquatic Those that lived among dinosaurs Supercroc and its bite force American Alligator 3000 lbs Saltwater crocodile 3700 lbs highest bite force ever measured Supercroc 31 000 lbs Weight of a mach truck Turtles Were like todays turtles but some reached giant sizes Lots of sea monsters Type of Plesiosaur We know their fin profiles and we know that they gave live birth Long Necked Plesiosaurs The supposed Loch Ness Monster Mosasaurs Aquatic animals closely related to todays monitor lizards like the Komodo dragon In the air were ptersaurs First ones had long tails some were filter feeders some had been found with fur Mammals appear at the same time as dinosaurs Mostly rat or possum sized throughout the age of the dinosaurs In the late Jurassic birds show up Bird shaped hip bones Beaks to crop plants Bird Hip Dinosaurs These constitute about half of all dinosaurs and is a group composed solely of herbi vores pg 129 Family tree of dinosaurs helpful for exam Ornithischia can be identified by 1 2 The first ones appear in the Middle Triassic Period 225 million years ago Like all early dinosaurs they were small 30 100lbs and were bipedal Test question dinosaurs start small and end big They had simple leaf shaped teeth that did not occlude and thus presumably ate suc culent plants like many lizards today with similar dentitions A major group of ornithischians were the Thyreophora Shield bearers or armored di nosaurs The diagnostic characteristic was armor or osteoderms like those on the backs of alligators Stegosaurs Supermodel for Stupidity Later forms of Thyreophora Characterized by Plates and spikes along or beside the backbone Two ton stegosaurs had 2 5 2 9oz brains Ours are 3 3 5lbs Their olfactory bulbs were relatively large suggesting a good sense of smell Ornithischian Group Cerapoda The distinguishing feature of the Cerapodans is a gap between the front and back teeth called a diastema Ornithopods We know more about their biology than any other dinosaurs because they were often gregarious herding animals Sometimes we find them in the thousands The distinguishing feature of Ornithopods is having front teeth well below the level of the back teeth Heterodinosaurs were one of the earliest types of ornithopods They were small herbi vores The teeth of these dinosaurs were mammal like Unfortunately we do not know the gender of any dinosaurs But in the case of Heterodontosaurus we have evidence of sexual dimorphism one sex bigger than the other Triceratops The largest and most famous ceratopsian Three horned faced dinosaur Often seen facing off with T Rex Triceratops were split into no less than 16 species The confusion came from confusion from naming of young males vs females OVER SPLITTING Likely Triceratops used horns for defense at times but one must keep
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