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
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