Dinosaurs
Dinosauria
3+ sacral vertebrae
Glenoid faces rear
Open acetabulum
Ball-shaped femoral head
Theropoda
pes longer than wide
Pes digit III longest, digit I short & elevated
manus digit IV greatly reduced & V absent
5+ sacral vertebrae
lots of axial skeleton pneumaticity
intramandibular joint
furcula
Ceratosauria
Earliest and most primitive Theropods
proximal tarsals fused
synsacrum
two pneumatic foramina (holes) on cervical vertebra
Coelophysoidea
Ceratosaurs with:
kinked snout
paired head crests
Neoceratosauria
Type of ceratosaurs
Include Abelisauridae and Ceratosaurus
Abelisaurs
Neoceratosaurs
Cretaceous predators
Short, deep skulls w/ large “horns” over eyes
Tetanurae
Theropods
teeth in jaws all rostral (forward) of orbit
manus digit IV lost
cranial zygapophyses on caudal vertebrae elongate
Spinosaurids
Cretaceous
Gondwana only (South America & Africa)
Huge!
Probably piscivorous (fish-eating)
very long skulls with crocodilian-like teeth
conical teeth without serrations
Ernst Stromer von Reichenbach
Discovered first Spinosaurid (was destroyed in WWII)
Spinosauridea includes
Spinosaurids and Megalosaurs
Rev William Buckland
Discovered Megalosaurus
Sir Richard Owen
Used fossils of Megalosaurus, Iguanodon, and Hylaeosaurus as the basis for defining the order Dinosauria in 1842
Avetheropoda
Derived from Tetanurae
extra fenestrae between antorbital fenestra and nares
caudal vertebrae in distal half of tail lack transverse processes
pubic boot
Avetheropoda consists of
Carnosaurs, Coelurosauria
Coelurosauria
Avetheropods with
only first ~15 caudal vertebrae have transverse processes
semilunate carpal
ischium < pubis
branched integumentary (skin) structures
Ornithomimids
Coelurosaur with long forelimbs
“bird mimics”
Therizinosaurs
Plant-eating Theropods
Deinonychosauria
Coeluosaurian Theropods
shoulder blade horizontal
glenoid faces laterally
coracoid elongate
Sauropodomorph
Saurischian dinosaurs
10 or more cervical vertebrae, usually very elongated
teeth serrated (in most groups), with denticles oriented 45° to tooth axis
bone between nares flattened
Large digit I on manus (claw)
cranium small compared to body
Sauropodomorpha consists of
Prosauropoda, Sauropoda
Prosauropods
first common dinosaurian herbivores
first large vertebrates to exploit niche of tall plants
known from every continent except Australia
lots of small teeth in long jaws
facultative bipeds
Slow
have enlarged claw on thum
Sauropods
Obligate quadrapeds
cervicalized thoracic vertebrae (? 11+ cervicals)
laminae & fossae on vertebrae
cervical vertebrae opisthocoelous
4+ sacral vertebrae
lots of caudal vertebrae
reduced # carpals to 3 or fewer
reduced # phalanges on manus digits IV & V
femur very long (longer than humerus + radius)
nares retracted caudally
Lamina
Thin ridge or sheet of bone
Fossa
Dead-end depression or excavation on bone surface
Amphiplatyan
Vertebrae flat on both ends
Amphicoelous
Vertebrae concave both ends
Procoelous
Vertebrae concave front, convex back
Opisthocoelous
Vertebrae convex front, concave back
Titanosaurs
Peg-toothed Sauropods
Diplodocoids
Neosauropods with:
extremely long necks and tails
peg-toothed
extreme narial retraction
very tall spinous processes on caudal thoracic, sacral, and proximal caudal vertebrae
Flagellicaudata
Neosauropods with:
distal tail composed of long, rod-like vertebrae (whip tail)
spinous processes on cervical and thoracic vertebrae forked
Diplodocidae
family of Sauropods associated with Morrison Formation
Edward Cope & Othniel Marsh
“Great Dinosaur Rush”
Flagellicaudata consists of
Diplodocidae, Dicraeosauridae
Macronaria
Neosauropods with nares > orbit
Camarasaurus
Macronaria
Most common dinosaur found in Morrison Formation
Brachiosauridae
Macronaria w/ arm > leg
Brachiosauridae + Titanosauria
Macronaria w/
kinked femur
vertebrae made of spongy bone
Sauropod hiatus
N. America: no sauropods between beginning & end of Late Cretaceous!
Titanosauria
Macronaria with
proximal and middle caudal vertebrae strongly procoelous
Includes smallest sauropods
Titanosauria
Gastroliths
Found in Sauropod gizzards
probably related to gut fermentation
Thyreophora
Name means “shield bearer”
basal ornithischians
Thyreophora
osteoderms (called “scutes”) in rows parallel to midline on both lateral and dorsal surfaces of torso
well-developed postorbital process
squat statue – short legs compared to body
all but the earliest forms were quadrupedal
Thyreophora consists of
Stegosauria and Ankylosauria
Both have toothless keratinous beak
Ankylosauria
broad compressed skull
armor covering cranial structures and
loss of all temporal fenestrae
fused sacral vertebrae, a synsacrum
closed acetabulum
horizontal ilium
lots of body armor
Two families of Ankylosauria
Nodosauridae, Ankylosauridae
Nodosauridae
Ankylosaur with
skull with no horns
large spikes on side
(small spikes or no spikes on back)
no tail club
Ankylosauridae
Ankylosaur with
skull with horns
large spikes on back
(small spikes or no spikes on sides)
tail club
Stegosauria
Member of Ankylosauria
parasagittal plates
A few had parascapular spines
Ornithopods
Ornithischian dinosaurs w/
teeth in maxilla more dorsal (higher) than those in premaxilla (i.e tooth rows at different heights)
Occlusal surface more dorsal than jaw joint
Premaxilla with elongate process
Crescent-shaped paroccipital process
Hypsilophodontida
Type of Ornithopods
small-medium sized
Bipedal
North America & Eurasia
originally thought to be monophyletic; is now known to be paraphyletic
Pleurokinesis
ability of maxilla to swing laterally (outward) when mouth is closing
First Ornithischians to evolve Pleurokinesis, opposable pinky
Hypsilophodontidae
Leaellynasaura
Small hypsilophodontid with enormous eyes
Iguanodontia
Ornithopods w/ a beak
premaxilla expanded and toothless
Facultative bipeds
Dr. Gideon Mantell
Discovered teeth of Iguanodon
Iguanodontoidea
Ornithopod w/
diastema between beak and maxillary teeth
narrowed hands
hoof-like pedal unguals
Hadrosauridae
“duck-billed” ornithopods
Facultative bipeds
well-developed dental batteries
loss of antorbital fenestra
8 sacral vertebrae
loss of digit I on manus
arms elongate (~ legs)
Hadrosaurine
Crestless and solid-crested hadrosaurs
Lambeosaurine
Hollow-crested hadrosaur
Marginocephalia
Shelf of bone extending back over occipital portion of skull
Shortened pubis
Widely-spaced acetabula (hip sockets)
Pachycephalosauria
“Bonehead” group of Marginocephalia
Homocephalidae
Pachycephalosaurs
Generally small
Flat, very bony heads
Pachycephalosauridae
Pachycephalosaur w/
Domed heads
Extremely thick, boney skull
Ceratopsia
Marginocephalids w/
keratinous beak
frill formed by parietals
triangular shaped skull
(when viewed dorsally)
“vaulted” or high palate
Two groups of Ceratopsia
Psittacosauridae, Neoceratopsia
Psittacosauridae
Member of Ceratopsia
Parrot-like, toothless beak
Neoceratopsia consists of
Proceratopsidae, Ceratopsidae
Aves
Theropods w/
arms > legs
anisodactyly
streptostylic quadrate
Evidence of Bolide Impact
crater
shocked minerals
tektites
impact-induced sedimentary deposits
enrichment of rare elements
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