the mesozoic was really cool

The Mesozoic was really cool

Mesozoic

Dinosaurs

First (reported) dinosaur discovery

Megalosaurus

Sir Richard Owen (1804 – 1892)

Dinosaur

Victorian Megalosaurus

‘Modern’ Megalosaurus

Megalosaurus

Archosaurs (all)

Archosaurs (fossil)

Archosaurs

Archosaurs and a few others (fossil)

Diapsida (living)

Archosaurs

The big picture

The big picture – a little more readable….

The big picture – a little more readable….

† Stem diapsids

The big picture – a little more readable….

† RhynchosaursProto - archosaurs

† Rhynchosaurs

Proto - archosaurs

The big picture – a little more readable….

Defining the Archosauria

*antorbital fenestra*mandibular fenestra*4th trochanter

antorbital fenestra

mandibular fenestra

Defining the Archosauria

alligator Tyrannosaurus

4th trochanter

Defining the Archosauria

Teeth in sockets

Defining the Archosauria

serrated teeth

Defining the Archosauria

†“Thecodonts”

†“Thecodonts” Proto – archosaurs ?

Primitive archosaurs ?

Crocodilians

Crocodilians

Mesozoic crocodilians

Simosuchus

Mesozoic crocodilians

Deinosuchus

Dinosaurs (sensu stricto)

Dinosauria

Dinosauria

Defining the Dinosauria

S-shaped neck

Forelimbs shorter than hindlimbs

About a dozen skeletal features

Defining the Dinosauria

Megalosaurus

Iguanodon

Iguanodon

Megalosaurus

Othniel Charles Marsh (1831 – 1899)

Edward Drinker Cope (1840 – 1897)

Dinosaur expedition – ca. 1870s

Dinosaur expedition – ca. 1990s

Classic Dinosaurs

Charles Robert Knight (1874 – 1953)

Charles Robert Knight

Robert T. Bakker

OLD

NEW

OLD

NEW

OLD

New

OLD

New

OLD

New

“Modern” Dinosaurs

“Dinosaurs” – 2 major groups

Saurischians Ornithischians

Ornithischians

Saurischians

Ornithischians “bird hips”

Saurischians “lizard hips”

Saurischia Ornithischia

Saurischians

Ornithischians

Ornithischia

Saurischia Ornithischia

Ornithischia

Predentary

Ornithischia

Ornithischia

Ornithischia

Stegasaurs

Ornithischia

Ankylosaurs

Ornithischia

Hadrosaurs

Ornithischia

Hadrosaurs

Parasaurolophus

Ornithischia

Pachyacephalosaurs

Ornithischia

?

Ornithischia

…it’s a guy thing

Ceratopsians

Ornithischia

Do behaviors and ecology and life history fossilize?

Ornithischia

Hadrosaur nest

Ornithischia

Hadrosaurs

visual displays?

vocalizations?

Ornithischia

Gastroliths

Psittacosaurus

Ornithischia

Psittacosaurus

Saurischians

Saurischians

Saurischia Ornithischia

subnarial foramentDefining the Saurichia

subnarial foramenDefining the Saurichia

Elongation of neck

All sorts of vertebral and forelimb modifications

Defining the Saurichia

Saurischian – two major groups

Sauropodomorphs

Saurischia

Theropods

Sauropodomorphs

Saurischians

Sauropodomorphs

Sauropodomorphs

Saurischians

Apatosaurus

“Brontosaurus”

A tail of two heads

Saurischians

Camarasaurus

Apatosaurus

A tail of two heads

Saurischians

wrong skull

Correct skull

Yale Peabody Museum

“Brontosaurus”

“Apatosaurus”

Saurischians

Brontosaurus

Apatosaurus

Sauropod niches

Saurischians

Gastroliths

Saurischians

Ornithischia

Theropods (non-avian)

Saurischians

Theropods

Saurischians

Three major types

Saurischians

Tyrannosaurus1. Slow moving

Ceratosaurus

Saurischians

2. Fast moving graspers

Saurischians

Fast moving graspers

Deinocheirus

Saurischians

3. Dromeosauridshind-claw-slashers

Saurischians

Velociraptor

Saurischians

Feathers?

Saurischians

Classic Velociraptor

Saurischians

“Modern” Velociraptor

Saurischians

Oviraptor

Saurischians

taxonomy is sometimes unfair

Oviraptor

Saurischians

Mesozoic Diapsids – a little clean-up

We actually aren’t dinosaurs

Pterosaurs

Archosaurs

Origins?

Smallish, arboreal, basal archosaurs

Pterodactylus

Quetzalcoatlus

13 m wingspan

Quadrupedal

How large?

Hatzegopteryx

How small?

Nemicolopterus

Paleobiology

Hollow bones

Air sacs

Keeled sternum

Nervous system

Some where fuzzy

Pycnofibres

warm blooded?

Social animals?

Pterosaur egg

Little known about reproduction

Flight

Flight

Relationship with Birds?

Sadly – they are extinct

Sauropterygians (Plesiosaurs)

Sauropterygians (Plesiosaurs)

Sauropterygians

Close to Lepidosaurs

Origin?Pachypleurosaurs

Keichousaurus

Kronosaurus 7 – 12 m

Plesiosaurus

Mary Anning (1799 – 1847)

Loch Ness

South Pacific - 1977

Off New Zealand - 1977

Sauropterygian ?

Sadly – it’s a basking shark

A rotting basking shark

Mosasaurs

Mosasaurs

Mosasaurs

Ichtyosaurs

Ichthyosaurs

embryo

Ichthyosaur and prey

Mary Anning - again

Convergent Evolution

Niche convergence