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