Early Mesozoic Era Jurassic and Triassic
Mesozoic 248-65 Myr P r e c a m b r i a n Eon P h a n e r o z o i c Proterozoic Archean Hadean Era Period Age (Myrs) Epoch C e n o z o i c M e s o z o i c P a l e o z o i c Geologic Time Scale Tertiary Quaternary Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordivician Cambrian Neogene Paleocene Age of the Earth 4600 Myrs (4.6 Byrs) Source: Geological Society of America (1999) 0.01 1.8 5.3 23.8 33.6 54.8 65 144 206 248 290 323 354 417 443 490 543 2500 3800 Holocene Pleistocene Pliocene Miocene Oligocene Eocene Paleocene
145 Million years 202 Million years 251 Million years Early Mesozoic: Triassic and Jurassic
Paleogeography Pangaea began to separate
Paleogeography Tethys seaway formed Site of modern Mediterranean
Major points about the Late Paleozoic 1.Therapsids established as the dominant land animals 2.Gymnosperms are the dominant land plants 3.Two major extinctions in the last few million years of the Paleozoic, the last being the largest in history 4.Rugose corals and Fusulinids completely wiped out 5.Brachiopods, Bryozoans, Ammonites and Therapsids nearly wiped out 6.All life on Earth is significantly affected 7.Cause still unknown; Massive flood basalts is the theory du jour
Early Mesozoic Bounded by mass extinctions Recovery from Permian mass extinction of: Fusulinids Lacy bryozoans Rugose corals Trilobites
Paleozoic vs. Mesozoic Rugosa & Tabulate Corals Hexacorals
Reefs - Hexacorals
Early Mesozoic Life Reefs Hexacorals Dominant reef builder Some resemble the extinct rugose corals
Paleozoic vs. Mesozoic Brachiopods Bivalves & Gastropods Bilateral Symmetry
Inoceramids
Paleozoic vs. Mesozoic Crinoids Echinoids (Sea Urchins)
Paleozoic vs. Mesozoic Trilobites Crustaceans
Paleozoic vs. Mesozoic Large Amphibians Frogs and Salamanders Paracyclotosaurus
Phytoplankton Erupt
http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html Foramifera: calcareous (CaCO 3 ) heterotrophs
http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html Diatoms: siliceous (SiO 2 ) phytoplankton (photosynthetic/au totrophs)
Radiolarians http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
Early Mesozoic Life Stromatolites returned temporarily to shallow water Ammonoids 2 genera diversity to 100 Mollusks, particularly bivalves abundant Sea urchins
Early Mesozoic Life Fishes continue to flourish - More modern - Skeletons of cartilage - Peg-like teeth - Scales covered bodies - Simple Jaws
Early Mesozoic Life Ammonoids Rapid evolution 1 million year range
Ammanoids - Parapuzosia
Early Mesozoic Life Belemnoids Squid-like relatives of Ammonoids
New Marine Predators!
Early Mesozoic Life Marine reptiles Placodonts Blunt-toothed shell crushers Broad armored bodies
Marine reptiles Early Mesozoic Life Nothosaurs Early Triassic May be first marine reptiles
Marine Reptiles Pleisiosaur
Early Mesozoic Life Plesiosaurs Evolved from nothosaurs
Plesiosaurs: Elasmosaurus
Largest- 150 ft long! Mosasaur
Mosasaur Kronosaurus
Ichthyosaurs Early Mesozoic Life Fish lizards Bore live young
Ichthyosaurus
Marine Reptile Relations
Giant Sea Turtles
Early Mesozoic Life on Land Tree-forming Gymnosperms Cycads Cycadeoids Ginkgos
Early Mesozoic Life on Land Mesozoic forests looked very different from modern forests
The Amniotes Diapsids (Includes lizards, dinosaurs & birds)) Classified based on skull structure Synapsids (Includes mammals) Anapsids (Includes turtles)
Mesozoic Reptiles Crocodiles Pterosaurs Dinosaurs & Birds Synapsids (Mammals) Anapsids (Turtles) Marine Reptiles Lizards & Snakes Archosaurs Diapsids
Early Permian - Labidosaurus Anapsids & Diapsids (True Reptiles)
Early Mesozoic Life on Land Early Mammals Mammals evolved from therapsids Small Thecodonts Dinosaur ancestors Upper portion of legs extended downward rather than sprawling
Early Mesozoic Life on Land Thecodont descendents Dinosaurs Bipedal Different skull More highly developed teeth Crocodiles
Early Mesozoic Life on Land Dinosaur evolution Bird- hipped Ornithiscian Herbivores Lizard-hipped Saurischian Herbivores Carnivores
The 2 Major Lines of Dinosaurs
Early Mesozoic Life on Land Pterosaurs Long wings Hollow bones Flight
Big Dinosaur Questions What are Dinosaurs? How do we understand Dinosaur behavior? Where dinosaurs warm-blooded (endotherms) or cold-blooded (ectotherms)? Did birds evolve from dinosaurs? What caused the extinction of the dinosaurs?
Dinosaurs vs. Reptiles 1. Upright posture Legs beneath the body rather than to the side 2. Unique arrangement of ankle hinge (and other skeletal differences)
Early Mesozoic Life on Land Sauropods Largest of all dinosaurs Jurassic Morrison Formation
Ornithischia Bird-Hipped Dinosaurs 1. Stegosaurs 2. Hadrosaurs 3. Ankylosaurs 4. Pachycephalosaurs 5. Ceratopsids All Herbivores
Hadrosaurs - Duck-billed Dinosaurs Ouranosaurus
Hadrosaurs Parasauralophus
Hadrosaurs Maiasaurus
Laellynasaura
Dinosaurs Maiosaura hatchling 50 cm long
Stegosaurs Stegosaurus
Ankylosaurids - Natures Tanks Euoplocephalus
Ankylosaurids ankylosaurus
Pachycephalosaurs - Bone Heads Pachycephalosaurus
Ceratopsids Horned Dinos Torosaurus
Triceratops Ceratopsids
Saurischia Reptile-Hipped Dinosaurs 1. Sauropods (Herbivores) 2. Theropods and Coelurosaurs (Carnosaurs) Aves (Birds) Herbivores and Carnivores Generally more mobile, pubis facing forward teeth on the rims of the jaws, two-legged and four-legged, dominated Early Mesozoic
Sauropods Seismosaurus X 20 Up to 90 feet long and 10 tons, lizardfeet (five toes like a reptile, nostrils sometimes on top, small brain (size of a kitten s), used gastroliths for digestion, herding animals
Barapasaurus Sauropods
apatosaurus Sauropods
Theropods Tyrannosaurus: up to 30 feet in length, several tons, size of a large elephant, Slow rambling gait?, large mouth for swallowing
Early Mesozoic Life on Land Allosaurus Largest carnivore! http://www.youtube.com/watch?v=3d4aa_l6c3w&feature=related
Theropods Velociraptor
allosaurus Theropods
Small Theropods: coelurosaurs Compsognathus
How do we know about Dinosaur Behavior?
Dino Nests
Dinosaur Trackways
How do we know about Dinosaur Color and Soft Stuff?
Skin Imprints Triceratops
Feathers
Brain Casts & Gizzard Stones Emphasizes smell and senses, not planning gastroliths
Ceratosaurus Color?
Horner (2001) Dinosaurs under the Big Sky
Warm vs. Cold Blood (Endotherms vs. Ectotherms) http://www.youtube.com/watch?v=ialpzhopjta http://www.youtube.com/watch?v=fo-yfw6voyw&feature=related
Predator/Prey Ratios What limits how many animals can exist on a patch of ground or seafloor?
Upright Posture & Fast Speeds
Problems - Food & Heat Loss & blood pressure
Fossilized dinosaur heart 4-chambered
Bone Structure
Bottom Line Some dinosaurs were endotherms (small theropods) and others were ectotherms (large sauropods)
Early Mesozoic Life on Land Archaeopteryx Missing link Feathered Breastbone
Paleogeography Pangaea began to separate
Paleogeography Tethys seaway formed Site of modern Mediterranean
Paleogeography Rifting began first in north, then spread south
Salt domes Thick evaporites built up in modern Gulf of Mexico Formed salt domes Petroleum reserves Paleogeography
Global warming Triassic Mass Extinction Volcanic activity released high volumes of CO 2 Number of leaf stomates increased Cells that utilize CO 2
Tectonic Events in Western U.S. Petrified Forest Chinle formation Utah and Arizona
Tectonic Events in Western U.S. Sundance Sea Global sea level rose Pacific flooded western U.S.
Tectonic Events in Western U.S. Grew by accretion of exotic terrane Island arc terranes Accreted Golconda Arc Microplates Accreted Sonomia Southeastern Oregon Northern California and Nevada
Tectonic Events in Western U.S. Accretion Golconda Arc Sonomia
Tectonic Events in Western U.S. Additional accretion Accretionary wedge Franciscan rocks Great Valley turbidites
Tectonic Events in Western U.S. Subduction led to intrusions Sierra Nevada batholiths
Mesozoic Batholiths
Tectonic Events in Western U.S. Sundance Sea Retreated as it filled with sediments Morrison Formation Reddish river sediments. Famous for the dinosaur fossils
Dinosaurs Oviraptor Egg stealer small at 0.7 m in size
Dinosaurs Protoarchtopterix Precursor of feathers 60 cm in size
Dinosaurs Protoarchaeopteryx Fossilized tail feathers
High Mesozoic Seas Low Transgression Regression
Sedimentary Sequences of NA Blue = No deposition
Cretaceous Seaway