Review Dinosaur Unit Definitions you should know Paleontologist someone who studies any aspect of ancient organism Fossils remains of ancient life o For dinosaurs we tend to think solely of these as bones Cladistics a method to organize physical characteristics of dinosaurs and discern relationships Finite Element Model used to find out the bite force of dinosaurs Encephalization Quotient a measure of brain size relative to the 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 thighbone First written account of dinosaurs come from China Richard Owen took stock of all crazy giants being found in Europe and noted they were different than the reptiles living today o Giant o 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 o Tracks o Skin Impressions o Gastroliths o Eggs and nests o Coprolites Where do we find dinosaurs o Sedimentary rocks rivers deserts etc o Very rarely find them in volcanic rocks or metamorphic rocks o Best place to find them are in badlands o Closets place to find dinosaurs is in Columbia Georgia o Will not find dinosaurs in Florida Dinosaurs have teeth in sockets like crocodiles and pterosaurs and are thus o Three or more sacral vertebrae fused backbones in hip region o Perforate acetabulae i e the hole where the thighbone attached goes all the way through the hip What makes a dinosaur a dinosaur close relatives Unique dinosaur feature 1 Unique dinosaur feature 2 o Hands with 3 main fingers Unique dinosaur feature 3 Dinosaur Renaissance Ostrom discovered Deinonychus o An athletic animal Robert 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 o Hips shaped like birds ornithischians o Hips shaped like lizards saursichians When Did Dinosaurs Live Lived 238 million years until 65 5 million years agi How do we know these ages o Look at radioactive isotopes in volcanic rocks o Compare original amount to final to assess age For dinosaur age uranium 235 is best o Carbon dating is too short to be of our use for dinosaurs Life of dinosaurs on Earth By the middle of the Cretaceous period flowering plants start showing up o These plants regenerate quickly can survive grazing 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 o American Alligator 3000 lbs o Saltwater crocodile 3700 lbs highest bite force ever measured o Supercroc 31 000 lbs weight of a mach truck Turtles o Were like todays turtles but some reached giant sizes Lots of sea monsters Type of Plesiosaur o We know their fin profiles and we know that they gave live birth Long Necked Plesiosaurs o The supposed Loch Ness Monster Mosasaurs o Aquatic animals closely related to todays monitor lizards like the Komodo dragon In the air were pterosaurs found with fur o First ones had long tails some were filter feeders some had been Mammals appear at the same time as dinosaurs o Mostly rat or possum sized throughout the age of dinosaurs In the late Jurassic birds show up Bird Hip Dinosaurs These constitute about half of all dinosaurs and is a group composed solely of herbivores pg 129 family tree of dinosaurs helpful for exam Ornithischia can be identified by 1 Bird shaped hip bones 2 Beaks to crop plants The first ones appear in the Middle Triassic Period 225 million years ago Like all early dinosaurs they were small 30 100 lbs and were bipedal o Remember dinosaurs start small and end big They had simple leaf shaped teeth that did not occlude and thus presumably ate succulent plants like many lizards today with similar dentitions A major group of ornithischians were the Thyreophora shield bearers or armored dinosaurs the backs of alligators o The diagnostic characteristic was armor or osteoderms like those on 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 5 Their olfactory bulbs were relatively large suggesting a good sense of smell The distinguishing feature of the Cerapodans is a gap between the front and Ornithischian Group Cerapoda back teeth called a diastema Ornithopods o We know more about their biology than any other dinosaurs because they were often gregarious herding animals o 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 o They were small herbivores 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 Brontosaurus Most famous diplodocid Tallest and perhaps the heaviest dinosaurs When it was found it had no head Some people think they reared up to feed others think they were more stationary Strange theory on how it got blood to its head maybe it had 6 hearts o These strange theories came up because this field of study was primarily made up of geologists Second major group of saurischians Includes the smallest dinosaurs known Theropod Carnivorous meat eating teeth Thin hollow bones Ovirapots These were the supposed egg robbers of Protoceratops nests o They were found to actually be protecting their young Might see a picture of this on the test identify what is the front back of the animal o Image in the book pg 78 Hadrosaurs after the other Duck like bill had tooth batteries hundreds of interlocked teeth used up one o They were self sharpening hard enamel on one side We know a lot about these because we have found tons of them o Have found their nesting grounds foot prints coprolites feces etc Crests on these dinosaurs didn t have holes so could not have been used as snorkel as some theorized T Rex Front part of its
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