1. Natural Sciences 360 Legacy of Life Lecture 13 Dr. Stuart S. Sumida Living Amphibians – the Environmental Monitors REPTILES AND THEIR RELATIVES

2. Living Frogs and Salamanders (Batrachia) – the environmental monitors.

3. Possible causes of amphibian declines include: Changes in climate - acid rain, ultraviolet radiation, drought, ozone layer depletion, etc. Loss of wetlands Invasive predators (such as trout and bullfrogs) Disease (bacteria, viruses, fungus) or parasites Pollution - pesticides, fertilizers, heavy metals, etc.

4. New Discovery! A LUNGLESS FROG!

5. What we used to think... Amphibians PRIMITIVE REPTILES “Mammal-like Reptiles” Mammals Birds

6. Um.........NO. Amphibians PRIMITIVE REPTILES “Mammal-like Reptiles” Mammals Birds

7. Panderichthyid Most Reptilia Sarcoptrygians Amphibians Diadectomorpha Synapsida (including Aves)

8. Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE)

9. Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota?

10. Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota? TETRAPODA

11. Panderichthyid Most Synapsida Reptilia Sarcoptrygians Amphibians Diadectomorpha (Mammals) (including Aves) AMNIOTA (FOR SURE) Amniota?

12. Amniotes: have four embryonic structures that reside outside the embryo to help it survive: Amnion Yolk sac Chorion Allantois

13. Other Sarcopterygians Panderichthyids Ichthyostegalia Dissorophoids Lissamphibia Anthracosauria Seymouriamorpha Diadectomorpha Amniota Sarcopterygii Tetrapoda The road to reptiles

14. Diadectomorpha: No intertemporal bone like other amniotes Very terrestrially adapted

15. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

16. Amniotes: have four embryonic structures that reside outside the embryo to help it survive: Amnion Yolk sac Chorion Allantois

17. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

18. Basal Synapsida (“Pelycosauria”): A single opening on side of skull

21. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

22. PARAREPTILIA Includes: Mesosauria Bolosauridae Procolophonia Paraiesauria

23. Mesosaurus: A member of Mesosauria

24. Eudibamis: a member of Bolosauridae

25. Eudibamus cursoris The earliest known bipedal vertebrate From the Early Permian (~280 million years old) of central Germany.

27. Bradysaurus: A member of the Parieasauria

28. Parieasaurs have lumpy, bumpy skulls Scutosaurus

29. Common North American painted turtle

31. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

32. Basal Captorhinid: Eocaptorhinus

33. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

34. Basal Diapsid: Petrolacosaurus Note: TWO holes (fenestrae) on side of skull Known back to Late Pennsylvanian

35. Diapsida includes: Many extinct forms Squamata Archosauromorpha Squamata includes living lizards and snakes.

36. Squamata: Lizards (including limbless lizards) Snakes

38. Crotaphytus (local, “collared lizard”)

39. “Horny-toads” are not toads.

40. Komodo dragon – largest living lizard

42. Meditteranean chaemelon

43. Monitor lizard

44. Amphisbaenia: limbless lizards

46. Cobra

47. Hog-nosed pit viper

48. Long-nosed vine snake

51. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

52. Archosauromorpha Includes: Crocodilians Numerous other extinct groups Pterosauria Dinosaurs Birds

54. Archosauria includes Crocodilians, Pterosaurs, Dinosaurs (including Birds), and a variety of other extinct groups.

55. Crocodylomorpha: Still extant - known from the Middle Triassic to present day. In brief: Low, flat skull. All but a few marine forms have 24 vertebrae cranial to the hip and 2 sacral vertebrae for attaching to the hip.

58. Alligator mississippiensis Note presence of bony “scutes” or osteoderms in skin.

60. Crocodilians are capable of a variety of types of locomotion: swimming; slow-sprawling walk; a moderate speed “high walk;” and even galloping in some young or smaller ones.

61. Some crocodilians have extremely complex social behavior and communication. Nile crocodile

62. Reconstruction of Sarcosuchus imperator (“Supercroc”) Over 40 feet long.

63. The Diversity of Extinct Marine Reptiles Examples of Convergent Evolution

64. “Duria antiquior”

65. Mesozoic marine reptiles are not dinosaurs. All are a variety of diapsid reptilies. We will survey them from approximately more primitive diapsid derivatives to somewhat more derived diapsid derivatives.

66. “ Amphibia” Amniota Seymouriamorpha Diadectomorpha Synapsida Parareptilia Captorhinidae Diapsida Archosauromorpha Amniota Reptilia

67. Reall the Basal Diapsid: Petrolacosaurus Note: TWO holes (fenestrae) on side of skull

68. Petrolacosaurus A primitive diapsid reptile Fenestrae color- coded green here

69. Mesozoic Marine Reptiles: Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

70. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

71. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

72. Placodonts were fusiform but large animals that lived in the Middle to Upper Triassic. Similar to manatees in the niche they filled.

73. Placodus gigas (type) Large teeth and palatal teeth indicate that it probably ate molluscs.

74. Placodus gigas

75. Paraplacodus

76. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

77. Nothosauria: Middle to Upper Triassic Very short snout end of skull, relatively longer caudal (postorbital) region of skull. Large, procumbent rostral (frontmost) teeth, often developed as fangs.

78. Often have elongate necks. Humerus and femur longer than more distal elements.

79. Nothosaurus mirabilus Reconstruction of skull and jaw musculature

80. Nothosaurus: reconstruction

81. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

82. Plesiosauria: Much larger than nothosaurs. Forelimbs and hindlimbs look much more similar. EXTREMELY elongate necks, even more so than nothosaurs. Note that despite paddle-like nature of hand (manus) and foot (pes), each still retains only five digits.

83. Plesiosaurs have HYPERPHALANGY: additional segments to the digits of the fingers and toes.

84. Cryptoclidus (plesiosaurid) Hydrothecrosaurus (elasmosaurid) Plesiosaurs have HYPERPHALANGY: additional segments to the digits of the fingers and toes.

85. Cryptoclidus (plesiosaurid) Hydrothecrosaurus (elasmosaurid)

86. Cryptocleidus (about 30 meters long)

87. Liopleurodon (about 80 feet long)

88. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

89. Ichthyosauria Triassic to Cretaceous – However, more extreme members of group lived in Jurassic and Cretaceous. Most highly specialized of marine reptiles. They converged on fish and cetacean forms. Highly modified skull: large orbit, reduced cheek region, elongate snout. Limbs modified into flippers; hyperdactyly. Viviperous: gave birth to live young.

90. Most highly specialized of marine reptiles. They converged on fish and cetacean forms. Mixosaurus reconstruction

91. Highly modified skull: large orbit, reduced cheek region, elongate snout. Most highly specialized of marine reptiles. They converged on fish and cetacean forms. Ichthyosaurus

92. Limbs modified into flippers; hyperdactyly and hyperphalyngy.

93. Juvenile at moment of birth.

94. Juvenile Ophthalmosaurus

95. Diapsida Sauropterygia Placodontia Nothosauria Pleisosauria Ichthyosauria Squamata Mosasauria

96. Mosasaurs: Not closely related to Sauropterygians or Ichthyosaurs. Actually highly derived members of the lizard family Varanidae. Late Cretaceous ecological replacements for Ichthyosauria.

97. Mosasaur Anatomy: Extremely elongate tail, body narrower and slimmer than other groups surveyed. (Probably swam in a more eel-like fashion.) However, neck, remains relatively short. Limbs modified for steering as opposed to propulsion. Have HYPER PHALANGY, but not hyerdactyly.

98. Plotosaurus, a mosasaur over 10 meters in length.