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Dinosaurs
From Your Questions
Dinosaur Distribution
Where are they found? United States, Argentina, Mongolia,
China, Central Asia, Africa, Antarctica, etc.
Did dinosaurs live in NY? If so, which ones?
Footprints of Coelophysis
Dinosaur Distribution
What environments did they inhabit?
River Valleys, plains, coastal lowlands, etc.
Did they live in cool climates? Probably, but still under
investigation
Dinosaur Distribution
How abundant were they? Probably at least as abundant as
Mammals are now. Some indications of large herds of
hundreds of individuals What were the relative abundances
of terrestrial and aquatic forms? Majority were terrestrial
Dinosaur Systematics & Biostratigraphy
What is the oldest dinosaur known? Triassic From what are they descended? Early “stem” reptiles To what are they related? Reptiles and probably birds How many species have been found? Hundreds, and counting! How long were they around? Approximately 180 Ma!
What caused their extinction? Multiple hypotheses:
Bolide impact Volcanism Climate change All of the above
Do they have any living descendents? Maybe!
Is There a Dinosaur in Your Backyard?
Archaeopteryx
Caudiopteryx
Confusciornis
Early Baby Bird135 Ma
Solnhofen Lagerstatten
Jurassic Solnhofen Limestone Soft tissues Archaeopteryx Hypersaline lagoon with very fine
micrites
Paleobiology of Dinosaurs
Why were they so large? Why not? Were they warm or cold blooded? Strong evidence favors warm-
blooded: Trackways – speed Haversian canals in bones Skeletal morphology – active habits Affiliation with birds
Paleobiology of Dinosaurs
What do we know about their diet and how do we know it?
Herbivores and carnivores: Distinction made on dentition, skeletal structure,
gastroliths Tooth morphology – clues to diet Coprolites – direct evidence
Morrison Formation – a dinosaur lagerstatte What do we know about their internal systems? Rare instances of preservation: Italian Alps specimen Was Tyrannosaurus rex a predator or scavenger?
Paleobiology of Dinosaurs
Has any soft tissue been found?
Have any babies ever been found in eggs?
Paleobiology of Dinosaurs
Has any soft tissue been found?
Have any babies ever been found in eggs?
Miscellaneous and/or Unanswerable Questions
What was their average life span? How intelligent were they? Did they have night vision? How did they interact with early
mammals? If they were around now, would they
eat people? Can they be cloned/grown (as in
Jurassic Park)?
Reptiles and Mammals
Reptile Adaptive Radiation included: Dinosaurs Therapsids – mammal-like reptiles Therapsids gave rise to mammals
What does it mean to be a mammal?
Characteristics of mammals?
Early Mammals
Small, rodent-like creatures Possibly nocturnal Some lines became extinct in
Cretaceous Late Cretaceous to Early Cenozoic
Adaptive Radiation
Major Groups of Extant Mammals
Placentals Marsupials Monotremes Edentates