3 2. What characters make a mammal? Suckle young,but may still lay eggsFurryEars with ear bonesSecondary palateSpecialised teeth -usually grow onceSimple jaw, complex jaw musclesWarm bloodedDiaphragmErect gait
4 2b. What skull characters make a mammal? Reptilian jawSimple teethQuadrateJaw hingeSquamosalArticularSimple biteDentaryMammalian jawArticular andquadrate nowear bonesSecondary palateSquamosalJaw hingeComplicatedbiteDentarySpecialised teethMasseter muscle
5 3. Mammal-like reptiles Thrinaxodon Some tooth specialisation SecondarypalateRigid spineComplex jaw,no ear bones?FurChewingmuscleEndotherm?DiaphragmSprawling gaitSmall size = small eggs, small hatchlings, much care,? suckling?
6 4. Mammals and dinosaursLimited Mesozoic radiation, all animals under 15kg. Mainlysmall scavengers and carnivores.MammalsCretaceousorigin. Evolvedon LaurentiaMarsupialsCretaceous origin,evolved on GondwanaMonotremesprobably evolved nearJurassic/Cretaceous boundary.Preciseancestry uncertainMultituberculatessuccessfulMesozoic clade,known principallyfrom teethMorganucodonLower Jurassictiny, agile carnivorewith complicated teeth
7 5. Palaeogene radiation of mammals Large flightless birdsradiated to become topterrestrial predatorsLarge crocodiles radiatedto becometop marinepredatorsMammals radiatedinto a large range of other niches.90% of mammalian groupsappeared within 10 Maof dinosaur extinction.Initially herbivores, omnivores,insectivores, scavengers.Gradually replaced birds and reptiles
8 6. Mammals on a cooling Earth Palaeogene EarthWarm,wet,low ice,abundant forestsMany isolated continentspromote intense speciationNeogene EarthCool, dry, large icecaps,evolution of grass,formation of widespreadsavannaHimalayas riseAmericas collideContinental collision and climatechange precipitate major extinctionmodern mammals survive and radiate
9 6b. Dinosaurs arrive Illium Birds Early Jurassic Ischium and pubis Sauropodslizard-hipped.VegetariansEvolved extremely large size,often in excess of 20 m in lengthand 50 tonness in weight.TheropodsLate Triassic.All theropodswere predators,includingTryannosaurus rex.Ornithischiansbird hipped dinosaursAll herbivores, includingarmoured formsIguanadontsand duck-billed dinosaurs.Highly modified teeth and jawsIlliumPubisIschiumArchosaurs