Dinosaur Paleobiology

Geology 331

Paleontology

Dinosaurs are

popular with

the public

Jack

Horner,

Montana

State

Univ.

Field Work

in Montana

A dinosaur “drumstick” in its field jacket.

Velociraptor

was a very

active

predator

Utahraptor waiting to ambush

Velociraptors hunted in packs

Abundant vascular canals in

dinosaur bone support the warm-

blooded theory

Thin section of dinosaur bone

www.bio.fsu.edu/erickson/histological_analysis.php

Heart Structure

2 Chambers:

Fish

3 Chambers:

Lizard

4 Chambers:

Birds & Mammals

Fossilized heart in an ornithopod.

CAT scan shows it has 4 chambers.

RV

LV

Evidence for Dinosaur Endothermy

• Erect and bipedal posture

• Bone histology – abundant vascular canals

• Head above the heart required high blood pressure and, thus, a four-chambered heart: 2 ventricles and 2 atriums.

• Fossilized four-chambered heart?

• Birds are descendants of theropods

• High latitude occurrences – how did they survive months of darkness?

• Predator:prey biomass ratio of 1:20 from the Late Cretaceous of Alberta similar to modern endotherms. Modern ectotherms are 1:3.

Dinosaur classification

Saurischian Ornithischian

Hip Bones: The Primary Homology

Difference Between the Two Major

Dinosaur Groups

Saurischian hip structure (theropod)

Ischium

Pubis

Saurischian hip structure (sauropod)

Ischium Pubis

Ornithiscian hip structure (stegosaur)

Ischium

Pubis

Excavating bones at Dinosaur

National Monument in Utah

A dinosaur

mummy

from

Mongolia

Coelophysis,

a late

Triassic

bipedal

ancestor

Tyrannosaurus rex, the

Cretaceous theropod everyone

loves to fear

Modern view of a T.rex

Peter Larson with Sue Hendrickson,

founder of the T. rex named “Sue”

I found it

first!

Sue on display in Chicago

T. rex, Stan Black Hills Institute

Tyrannosaurs, Carnegie Museum, 2009

Mechanical

model of T. rex

shatters a large

bone

Peter Larson with a Nanotyrannosaurus skull

at his lab at the Black Hills Institute, SD

More scenes at the

Black Hills Institute, SD

Compsognathus,

a chicken-sized

theropod. It’s

skeleton is similar

to Archaeopteryx.

The “compies” of

Jurassic Park.

Archaeopteryx,

the first bird. Its

skeleton is nearly

identical to

Compsognathus.

A feathered(?) Velociraptor

Apatosaurus or Brontosaurus, the

classic sauropod

Apatosaurus out for a stroll

A modern view of sauropods

Sauropod trackways showing no evidence

of tail dragging.

Diplodocus - a gracile sauropod

Sauropods, Carnegie

Museum, 2008

Sauropods, Carnegie

Museum, 2008

Sauropods, Carnegie

Museum, 2008

Sauropods, Carnegie Museum, 2008

Sauropods, Carnegie Museum, 2008 Looks like

your diet is

working!

Sauropods eating a coniferous forest

The massive digestive system of a

sauropod, note the large gizzard

Inside of sauropod gizzard, note the

gastroliths for grinding food

Sauropod gastroliths

Sauropods protecting

their young, South

America

Theropod tracks in Utah

Iguanodon,

an

ornithopod

A Cretaceous ornithopod

Crested hadrosaur or “duck-bill”

Duck-billed hadrosaur

Hadrosaur

barbershop

wall chart

Skull of a pachycephalosaur

Head butting by pachycephalosaurs

Stegosaurus

Stegosaurus

Ankylosaurus

Protoceratops from Mongolia

Triceratops at the Smithsonian Institution