Dinosaurs From Your Questions

What events separate the periods of the Mesozoic  Mass extinctions – mainly of cephalopods  First appearances of new cephalopods  First appearances of various types of “plankton”

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  Why did they first appear in S. America?  Favorable environmental conditions/Ecological opportunity

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

What was the vegetation like?  Seed Ferns  Gingkos  Flowering plants in Cretaceous

What ecologies existed (food chains)?  Terrestrial vegetation  Herbivorous insects, amphibians, reptiles, dinosaurs, mammals  Carnivorous amphibians, reptiles, dinosaurs and mammals  Scavenging amphibians, reptiles, dinosaurs and mammals  Decomposers: fungi, bacteria, etc.

What is the difference between reptiles and dinosaurs?  Reptiles and dinosaurs descended from “primitive” “stem reptiles”  Major differences in skull structure  Major differences in pelvic structure and leg orientation  Probable differences in thermal regulation

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!

Ornithischians and Saurischians  Differences in pelvic structure  Functional differences?  Relationship to bipedalism?

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 Feathers as insulation on some

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  How die they communicate?  Vocalization with and without “reverb” chambers in skull.  How do we know what we know?  The fossils!

Paleobiology of Dinosaurs  Has any soft tissue been found?  Have any babies ever been found in eggs?  Did they have scales or feathers?  How long did it take them to grow so large?

Paleobiology of Dinosaurs  Have any babies ever been found in eggs?

Dinosaur Fact File  What was the first dinosaur?  Herrarasaurus from Argentina  What was the smallest dinosaur?  Micropachycephalosaurus - 20 inches long  Echinodon - 24 inches long  Saltopus - 24 inches long  Microceratops - 30 inches long  Pisanosaurus - 36 inches long

Dinosaur Fact File: Largest Diplodocids and Titanosaurs  Seismosaurus 84 feet (25.6 m) 150 feet (45.7 m) 200,000 pounds (90,720 kg) Seismosaurus - diplodocid Argentinasaurus - titanosaur Bruhathkayosaurus - titanosaur

Dinosaur Fact File  Could dinosaurs swim?  Yes, evidence includes toe scratches on bottom sediments.  Did “Cave men” and dinosaurs co-exist?  NO!!! They are separated in time by nearly 65 Ma (with apologies to Fred Flintstone and Dino)  Was the Loch Ness Monster real?  NO!!! It has been exposed as a hoax by the person that faked the most widely cited photographic “evidence.”

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 Bird 135 Ma

Miscellaneous and/or Unanswerable Questions  What was their average life span?  How intelligent were they?  Could they talk? – probable vocal abilities  Were they“mean”?  Why is the source of children’s fascination with dinosaurs?  How would dinosaurs and humans coexist?  What color were they?  Did they have territorial battles?  Were some dinosaurs monogamous?

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