1. Dinosauria: open acetabulum
2. Ornithischia: process of pelvis points backward
3. Saurischia: metacarpal of digit I robust and twisted
4. Genasauria: cheeks
5. ?no shared derived characters
Lesothosaurus, Early Jurassic, Stormberg Group, South Africa6. Thyreophora: armor
Scelidosaurus, Early Jurassic, Lias, England9. Stegosauria: armor as plates or spines on back
Scutellosaurus, Early Jurassic, Glen Canyon Group, Arizona, USA
Ankylosaurus, Late Cretaceous, Judith River beds, Alberta, Canada12. Nodosauridae: complex palate and large armor plate on top of center of skull
Pinacosaurus, Late Cretaceous, Mongolia
Euplocephalus, Late Cretaceous, Judith River beds, Alberta, Canada
Nodosaurus, Early Cretaceous, Cloverly Formation, Montana13. Kentrosauridae: armor as spines on most of back
Edmontonia, Late Cretaceous, Judith River beds, Alberta, Canada
Kentrosaurus, Late Jurassic, Tendaguru Formation, Tanzania14. Stegosauridae: armor as plates on back
Stegosaurus, Late Jurassic, Morrison Formation, western USA15. Marginocephalia: bony shelf on back of head
Prenalocephale, Late Cretaceous, Mongolia17. Ceratopsia: rostral bone on snout
Pachycephalosaurus, Late Cretaceous, Judith River beds, Alberta, Canada
Psittacosaurus, Early Cretaceous, Mongolia19. Neoceratopsia: long frill
Protoceratops, Late Cretaceous, Mongolia20. Ornithopoda: jaw joint below tooth rows
Triceratops, Late Cretaceous, Hell Creek beds, Western USA
Heterodontosaurus, Early Jurassic, Stormberg Group, South Africa22. no name (Hypsilophodontidae + Iguanodontidae + Hadrosauridae): prepubic process well developed
Hypsilophodon, Early Cretaceous, England24. no name (Iguanodontidae + Hadrosauridae): reduction in digit I of hand
Iguanodon, Early Cretaceous, Wealden beds, England and Belgium26. Hadrosauria: loss of digit 1 and duck-like snout
Camptosaurus, Late Jurassic, Morrison Formation, western USA
Ouranosaurus, Early Cretaceous, Niger
Hadrosaurus, Late Cretaceous, New Jersey, USA
Saurolophus, Late Cretaceous, Mongolia
Anatotitan, Late Cretaceous, Hell Creek beds, Montana, USA
Maiasaura, Late Cretaceous, Two Medicine Formation, Montana, USA
Parasaurolophus, Late Cretaceous, Judith River beds, Alberta, Canada
Corythosaurus, Late Cretaceous, Judith River beds, Alberta, Canada
1. Dinosauria: open acetabulum
2. Saurischia: metacarpal of digit I robust and twisted
3. Ornithischia: process of pelvis points backward
4. ? no shared derived characters
Herrerasaurus, Ischigualasto Formation, Argentina5. Sauropodomorpha: small head and long neck
Plateosaurus, Late Triassic, Keuper, Germany8. Brachiosauridae: forelimbs as long as, or longer than, hind limbs
Brachiosaurus, Late Jurassic, Morrison Formation, Western USA; Tendaguru Formation, Tanzania9. Diplodocidae: teeth restricted to front of mouth
Ultrasaurus, Late Jurassic, Morrison Formation, Western USA
Camarasaurus, Late Jurassic, Morrison Formation, Western USA
Diplodocus, Late Jurassic, Morrison Formation, Western USA10. Titanosauridae: Armor
Seismosaurus, Late Jurassic, Morrison Formation, Western USA
Saltosaurus, Creataceous, Argentina11. Theropoda: three toed foot
Ceratosaurus, Late Jurassic, Morrison Formation, Western USA13. Tetanuria: digits IV and V of hand lost
Dilophosaurus, Early Jurassic, Glen Canyon Group, Arizona, USA
Coelophysis, Late Triassic, Chinle Group, Arizona, USA
Baryonyx, Early Cretaceous, Wealden, England
Spinosaurus, Late Cretaceous, Egypt
Allosaurus, Late Jurassic, Morrison Formation, Western USA15. Arctometatarsalia: proximally pinched metatarsal III of pes
Troodon, Late Cretaceous, Judith River beds, Alberta, Canada18. Ornithomimosauria: manus with nearly equal length metacarpals
Struthiomimus, Late Cretaceous, Judith River beds19. Tyrannosauridae
Gallimimus, Early Cretaceous, Judith River beds
Ornithomimus, Late Cretaceous, Mongolia
Deinocheirus, Late Cretaceous, Mongolia
Albertosaurus, Late Cretaceous, Judith River beds, Alberta, Canada20. Coelurosauria: long arms
Tarbosaurus, Late Cretaceous, Mongolia
Tyrannosaurus, Late Cretaceous, Hell Creek Formation, Montana
Therizinosaurus, Late Cretaceous, Mongolia22. ? no shared derived characters
Segnosaurus, Late Cretaceous, Mongolia
Ornitholestes, Late Jurassic, Morrison Formation, Western USA23. ? no shared derived characters
Compsognathus, Late Jurassic, Solenhofen Limestone, Germany24. Oviraptorosauria: skull deep, highly fenestrate, lacking teeth
Sinosauropteryx, Early Cretaceous, Liaoning lake beds, China
Oviraptor, Late Cretaceous, Mongolia25. Maniraptora: semilunate carpal
Caudipteryx, Early Cretaceous, Liaoning lake beds, China
Deinonychus, Early Cretaceous, Cloverly Formation, Wyoming, USA27. Avialae: flight feathers on arm and hand
Velociraptor, Late Cretaceous, Mongolia
Mononykus, Late Cretaceous, Mongolia28. ? no shared derived characters
Confuciusornis, Early Cretaceous, Liaoning lake beds, China
Archaeopteryx, Late Jurassic, Solenhofen Limestone, Germany29. Aves: loss of teeth, spike-like manus