Dinosaurs

1
Dinosaurs

• From Your Questions

2
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

3
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

4
Dinosaur Distribution

• What environments did they inhabit?
• River Valleys, plains, coastal lowlands, etc.
• Did they live in cool climates?
• Probably, but still under investigation

5
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

6
What was the vegetation like?

• Seed Ferns
• Gingkos
• Flowering plants in Cretaceous

7
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.

8
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

9
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!

10
Ornithischians and Saurischians

• Differences in pelvic structure
• Functional differences?
• Relationship to bipedalism?

11
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

12
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!

13
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?

14
Paleobiology of Dinosaurs

• Have any babies ever been found in eggs?

15
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

16
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
17
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.

18
What caused their extinction?

• Multiple hypotheses
• Bolide impact
• Volcanism
• Climate change
• All of the above
• Do they have any living descendents?
• Maybe!

19
Is There a Dinosaur in Your Backyard?
Confusciornis
Archaeopteryx
Early Baby Bird 135 Ma
Caudiopteryx
20
Miscellaneous and/or Unanswerable Questions

• What was their average life span?
• How intelligent were they?
• Could they talk? probable vocal abilities
• Were theymean?
• Why is the source of childrens fascination with
  dinosaurs?
• How would dinosaurs and humans coexist?
• What color were they?
• Did they have territorial battles?
• Were some dinosaurs monogamous?

21
Reptiles and Mammals

• Reptile Adaptive Radiation included
• Dinosaurs
• Therapsids mammal-like reptiles
• Therapsids gave rise to mammals

22
What does it mean to be a mammal?

• Characteristics of mammals?

23
Early Mammals

• Small, rodent-like creatures
• Possibly nocturnal
• Some lines became extinct in Cretaceous
• Late Cretaceous to Early Cenozoic Adaptive
  Radiation

24
Major Groups of Extant Mammals

• Placentals
• Marsupials
• Monotremes
• Edentates