Dinosaurs Midterm 2

Sauriscia Defining Characteristic

Hips - Lizard, pubis opposite from ischium

Theropoda primitive form

Herrerasaurus

Theropoda Big 3

Ceratosaurs

Carnosaurs

Coelurosaurs

Ceratosaurs distinguishing features (2)

1. notch between premaxilla and maxilla

2. four fingers

Carnosaurs distinguishing features (3)

1. foramen in lacrimal

2. short vertebral spines at base of neck

3. pronged chevrons

Spinosaurs reasons for being piscivorous (fish eaters) (4)

1. unserrated teeth

2. wide spaces between teeth

3. long, narrow skulls

4. short arms with large claws

What are spinosaurs

Theropods

coelurosaurs distinguishing features (3)

1. lots of pneumatization in cervical and dorsal vertebrae

2. long front limbs

3. arctometatarsalian foot (pinched toe bone - metatarsal)

famous coelurosaurs (3)

1. dromeosaurs (raptors)

2. tyrannosaurs

3. modern birds

Early use of wings and feathers

Display

what do birds and dinosaurs share

1. air filled vertebrae

2. feathers

3. three toed feet

4. furcula (wishbone)

Sauropodomorph major groups

1. prosaurodpods (a grade - excluding some descendents)

2. sauropods (a clade)

why can’t sauropod necks go straight up?

shape of neck bones

are sauropods saurischian or ornithischian?

saurischian

are theropods saurischian or ornithischian?

saurischian

3 ways to make sauropods have long necks

1. make bones longer

2. move shoulders back so dorsal becomes cervical

3. add neck bones during embryonic development

why were sauropods able to get so big and have long necks?

pneumatic bones are able to be supported because they aren’t so heavy

why do we use shoulder vertebrae to distinguish sauropods?

skulls are super rare

Ornithischia distinguishing features (4)

1. Hip - bird, pubis parallel with ischium

2. palpebral bone (in eyes)

3. predentary bone

4. ossified tendons

What mouth did onithischians have

beaks

what does a narrow beak tell us about feeding

browser, picky

what does a wide beak tell us about feeding

grazer, less picky

evidence for having cheeks (2)

1. ridges along dentary and maxilla for muscle attachment

2. inset teeth

why have cheeks, diastema (space between upper and lower jaw)?

tongue can manipulate food

what teeth did ornithischians have?

ancestral had leaf shaped

advanced had asymmetrical

why asymmetrical enamel

uneven wear is self-sharpening

what are dental batteries

stacks of teeth

which 2 clades had dental batteries

hadrosaurids (duck billed)

ceratopsians (triceratops)

What are thyreophoran dinosaurs

armored dinosaurs (have osteoderms)

why are osteoderms full of holes or grooves or tubes

had blood vessels

sauropods why have long necks

to eat high in trees XX

they eat from vast low areas VV

tetanurum theropod

slender tail, teeth not past eye socket

what is a predentary

beak, no teeth

whats different about ornithischian pubis

goes forward and back

why couldn’t sauropods chew their food

no cheeks

what dinosaurs have diastema (cheeks)

ornithischians

function of stegosaurs plates

display and protection

what is different about jaw joint of herbivores

separated, lower jawbone dropped down to prioritize power over speed

why have dental battery

hard to digest plant fibers

proof that the big heads smacked into eachother

infections from break throughs

primary evidence of herds

large bonebeds of a single species

which leg is fastest

longer shin vs femur

wings and feathers on theropods used for

display

vertebrae used for classification in sauropods why

skulls are fragile and rare

mosasaurs are closely related to

lizards and snakes

most aquatic Mesozoic “reptiles” are characterized by

live birth

with the exception of the dentary, the bones of the “reptilian” lower jaw…

move to the ear

2 groups within ankylosaurs

ankylosaurids

nodosaurids

2 ornithopod groups

iguanodontids

hardosaurids

iguanodontid hands

giant thumb spike for defense

grasping pinky

2 groups within hadrosaurids

lambeosaurines

hadrosaurines

lambeosaurines distinguishing features (1)

long tubes and crest on head used for amplification of sound

hadrosaurine distinguishing features (3)

heavy built skull

wider snouts

large nostrils

marginocephalia definition

has shelf on the back side (posterior edge) of skull

Megalocephalia major 2 groups

pachycephalosaurs

ceratopsians

why ceratopsians only in nothern hemisphere

Pangea had broken up and they couldn’t cross over

evidence ceratopsians were herd animals

bonebed in canada with thousands of individuals

primitive ceratopsian

Psittacosaurus, had cheek horns (jugal horns) and upper beak bone

2 clades of ceratopsians

pachyrhinosaurines (cantrosaurines)

chasmosaurines (ceratopsines)

pachyrhinosaurines distinguishing features (2)

short deep faces

large nasal horns

chasmosaurine distinguishing features

long faces or snouts with short nasal horns

many have large frills

which clade is triceratops

chasmosaurine

pachycephalosaurs thick skull used for what and why know that

headbutting - evidenced by damage

is pterosauria dinosaur

not a dinosaur but close relative, shares hinge ankle

pterosauria 2 major groups

rhamphorhynchoids (a grade)

pterodactyloids (a clade)

distinguishing feature of rhamphorhynchoids

long tails

distinguishing feature of pterodactyloids

super short tail

what is a grade

paraphyly - does not include all descendents

what makes up the pterosaur wing

4th finger is super long, skin membrane

why did pterosaurs have such extremely pneumatic skeletons?

so they could fly

what is cool about pterosaur skulls

a ton of diversity

how did pterosaurs get around when on the ground and how do we know

quadrupedal, folded wings and walked on fingers, evidenced by tracks

are Ichthyosaurs dinosaurs

NOT dinosaurs

ichthyosaurs breath water or air

breath air

plesiosaurs related to who

related to snakes

ichthyosaurs and plesiosaurs how give birth and how we know that

live birth - evidenced by babies inside mother skeletons

ichthyosaurs or plesiosaurs have long necks

plesiosaurs

mosasaurs how different from icthysoaurs (3)

not have dorsal fin

smaller eyes

larger hind paddles

close living relatives of mosasaurs

lizards

why permits for dino digging

lumper

groups several genera or species into a single species

why need permit

for federal lands to protect fossils from random or commercial people

why use micro computed tomography for preparation of fossils

doesn’t damage, can see detail

osteology

study of the bones

taphonomy

how did the dinosaur die

who names dinosaurs

first to publish on the specimen

splitter

thinks most things they find are new genera or species

publication

formal report to scientists about everything