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 Bird135 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