Natural Sciences 360 Legacy of Life Lecture 14 Dr. Stuart S. Sumida

1. Natural Sciences 360 Legacy of Life Lecture 14 Dr. Stuart S. Sumida The Diversity of Extinct Flying Reptiles: Examples of Convergent Evolution Starting Dinosaurs

2. Remember, we’re studying AMNIOTES. • Defined by: • EMBRYOLOGICAL FEATURES: amnion, chorion, allantois, yolk sac. • ANATOMICAL FEATURES: lack of an intertemporal bone. • ALSO, FUNCTIONAL FEATURES: • Costal breathing (inhaling using movement of the ribs). • Active exhalation using movement of ribs to push air out.

3. ARCHOSAURIA

4. ARCHOSAURS ARE DIAPSID REPTILES • ARCHOSAURIA INCLUDES: • Crocodylomorpha • Pterosauria • Dinosasuria • Aves (Birds)

5. Crocodylomorpha Pterosauria Eoraptor Herrerasauridae Saurischia Ornithischia Archosauria

6. Crocodylomorpha PterosauriaEoraptor Herrerasauridae Saurischia Ornithischia Archosauria

7. PTEROSAURIA: Flying Reptiles of the Mesozoic They are the closest relatives of dinosaurs, but they are not actually dinosaurs. They used elongate 4th finger to support a wing. The wing DID NOT attach to the leg.

8. Rhamphorhynchus sp.

9. Reconstruction of the pterosaur Eudimorphodon in pronograde, bipedal walking.

10. TERMS FOR POSTURE Pronograde: backbone parallel to ground Orthograde: backbone perpendicular to ground BIPEDAL and QUADRUPEDAL are not postural terms.

11. Pterydactylus

12. Reconstruction of Pteranodon

13. Reconstruction of Pteranodon

14. Some pterodactyloids had wildly developed skulls. This one, Pterodaustro (Upper Cretaceous of Argentina) had numerous teeth that probably probably functioned similar to whale baleen.

15. Comparative wing structure in flying vertebrates

17. Two hypotheses of wing reconstruction in Pteranodon.

18. The largest of the Late Cretaceous pterosaurs were probably so large they were restricted to being gliders only. Quetzalcoatlus northropi had a wingspan of approximately 11-13 meters.

19. Humerus of Quetzalcoatlus northropi – over ½ meter long. Humerus (young?) Q. northropi – about 0.25 meter long.

20. Quetzalcoatlus northropi had a wingspan of approximately 11-13 meters.

21. DINOSAURIA

22. Crocodylomorpha Pterosauria Eoraptor Herrerasauridae Saurischia Ornithischia Dinosauria Archosauria

23. THE MOST PRIMITIVE DINOSAURS Crocodylomorpha Pterosauria Eoraptor Herrerasauridae Saurischia Ornithischia

24. Eoraptor lunensis (“Dawn Raptor”) • From the Upper Triassic of Argentina. • Thought to be amongst the most primitive of dinosaurs. • Its hip is like that of dinosaurs: it has a “perforate” acetabulum. (A hole in the hip socket.)

25. Eoraptor lunensis (“Dawn Raptor”)

26. Eoraptor

27. CT Scan of Eoraptor skull.

28. A perforate acetabulum

29. EoraptorReconstruction

30. Eoraptor Reconstruction

31. Crocodylomorpha Pterosauria EoraptorHerrerasauridae Saurischia Ornithischia

32. Herrerasauridae: Upper Triassic of Argentina 2 – 4.5 meters long. Long, low skull that is as long as the femur. 24 presacral vertebrae; and the vertebrae are relatively shorter than more primitive forms.

33. Herrerasaurus ischigualastensis

34. Stereo-pair view of Herrerasaurus ischigualastensisskull.

35. Herrerasaurus ischigualastensis Skull, specimen drawing. Long, low skull that is as long as the femur.

36. Herrerasaurus ischigualastensis Skull reconstruction

37. Herrerasaurus ischigualastensis Reconstruction 24 presacral vertebrae; and the vertebrae are relatively shorter than more primitive forms.

38. Herrerasaurus ischigualastensis

39. Herrerasaurus ischigualastensis

40. Dinosaurian groups more derived than Herrerasaurs may be divided into two groups based on hip construction: SAURISCHIAN ORNITHISCHIAN (Note position of pubis.)