dinosaurs exam 2 review

saurischians

-blade like serrated teeth
-promaxillary fenestra
-intramandibular joint
-enlarged hands with increased grasping abilities
-bipedal
-birdlike feet
-lightly built theropod skulls
-feathers
-pneumatic vertebrae

carnosaurs

-meat lizard
-large with short necks and small forelimbs

coelurosaurs

-hollow tail lizard
-smaller with longer necks and longer forelimbs

herrerasaurs

-one of the most primitive dinosaurs
-caused saurischian and ornithischian clades to split
-was originally thought to be a theropod

theropods

-blade like serrated teeth
-promaxillary
-intramandibular joint
-enlarged hands
-predatory
-all bipedal
-tyrannosaurus, velociraptor, allosaurus
-many were feathered
-birdlike feet
-sharp claws
-lightly built skulls

coelurosauria

-closest related to birds
-enlarged brain, tridactyl hand with long 2nd and 3rd digits, feathers, hinge-like ankles

furcula

-fused collar bones
-strengthen skeleton & hold wings

feathered theropods

-archaeopteryx & yutyrannus
-insulation/display rather than flight

ceratosaurs

-six or more sacral vertebrae
-very deep coracoids
-small forelimbs
-4 fingers
-limusaurus, aucasaurus, abelisaurus

carnosaurs

-extra opening in maxillary
-very large nasal bones
-allosaurus & giganotosaurus

therizinosaurs

-small skulls
-long necks
-huge claws
-short legs

oviraptorids

-toothless jaws
-short snouts
-boxy skulls
-large fenestra in mandible
-crest of sponge-like bone on tip of snout

prosauropoda

-small teeth with large serrations (leaf shaped teeth)
-short necks - not as long as sauropods
-jaw articulation offset
-poorly pneumatized vertebrae
-obligate quadrupeds
-can be bipedal (primitive)
-no sharp claws
-plant eaters
-long necks go side to side
-teeth look like iguanas

difference between sauropods and prosauropods

-prosauropods have small 5th digit
-should vertebrae is used for naming because skulls are too fragile

diplodocus

-only teeth in front, possibly a beak

camarasaurus

-rounded nose unlike Brachiosaurus

brachiosaurus

-enlarged nostrils above the eye
-backwards L shape
-longer humerus than femur
-dip in premaxilla

shunosaurus

-teeth facing forward
-no dip in premaxilla unlike the brachiosaurus

brontosaurus

-actually an apatosaurus with the gead of a camarasaurus - has been fixed

sauropod long necks

-allows feeding over wide arc
-robbing vertebrae from back
-adding extra vertebrae (early embryonic development)
-elongating individual vertebrae

pneumatic vertebrae

-added air so it was lighter
-keeps necks strong but light
-feed with extended necks

smaller skulls

longer necks

diplodocus could not raise head above shoulders

-necks were straight but heads were angled down, necks were not flexible
-good for side to side

high browser

-longer humerus than femur, reaching into trees to feecd from branches

grazers

-no grasses, likely ferns
-low energy to graze on the ground
-longer femur than humerus

ornithischia

-self sharpening teeth
-feathers
-scales
-cheeks
-ridges in maxilla and dentary
-longest lived dinosaur
-middle jurassic to end cretaceous

dental batteries

-teeth stackes on each other in sockets
-constantly had teeth, not a big deal to lose

neornithischia

-self-sharpening teeth
-thick enamel on outside, thin inside

bipeds

-walks on 2 legs
-much shorter tibia/fibula
-how the head is anchored

facultative biped

-walks on 4 but can on 2 for mating/eating
-head anchored more back (prosauropods)

iguanodon

-spikey thumb claw
-opposable pinky finger with 6 bones to grasp things with
-3 fingers to walk on like hooves

hadrosaurine

-heavily built
-wide snouts
-dental batteries
-enlarged nares
-extra motion in jaw

lambeosaurine

-crested skulls (impacted by age & sex)
-relatively lightly built
-narrower snouts
-dental batteries
-extra motion in jaw

hadrosaurid skulls

-diastema: gap between beak/premaxilla teeth and back teeth
-there so the tongue can bring food from the cheek to the mouth
-cheeks: there to catch the food that falls out of the teeth during grinding
-extra skull joints: allows teeth on maxilla to move back and forth
-better grinds food
-beaks: broad with no teeth

lambeosaurine tubes and crests

-display and sound

cheeks

-ornithischians
-ridges on skull above teeth is where muscles would have connected

beak shape

-wider beak = grazer
-narrow beak = browsers
-use beaks to clip vegetation before chewing

thyreophorans

-stegosauria & ankylosauria
-armore & dermal ossicles

stegosaurid

-long, narrow skull
-standard ornithischian beaks
-rows of large spikes or plates along back
-late jurassic is stegosaurus

huyanosaurus

-middle jurassic
-most primitive stegosaurid
--combination of spikes and plates

dermal ossicles

-located within the skin, covered with keratinous sheath, in life they were covered by blood vessles (in grooves)

plates of stegosaurus

-arrangement: 2 separate rows (staggered)
-display & protection

stegosaurs & ankylosaurs

-they evolved at around the same time but ankylosaurs were around for longer
-skull shape

nodosauridae

-long skulls
-large projection on scapula
-nodosaurs have elongated snouts and no club on their tail

ankylosauridae

-short, wide skull, club tail
-triangular head
-hornlets on skull
-complex nasal chambers
-tail club made of derived ossicles

ceratopsians

-big crest

pachycephalosaurs

-dome skull

marginocephalia

-shelf on back of skull
-herbivores
-late cretaceous
-north america and asia - no link between southern & northern continents

bipedal marginocephalians

-some were bipedal because their skulls were too heavy

ceratopsia

-neomorph - bone in front of nasal
-jugals (cheek bones) flair laterally & have a horn coming out of it

psittacosaurus

-bipedal, small frill, quills/bristles on tail, skin & color pattern preserved, upper body is darker than underbody, most accurate reconstruction of any dinosaur, cloaca was described but insides were not preserved

protoceratops

-larger frill than psittacosaurus but smaller than ceratopsids, no skull horns, 120 million years old, ontogeny series & sexual dimorphism, quadrupedal

chasmosaurines

-long skull, short nasal horn, long orbital horns

pachyrhinosaurines

-short skull, long nasal horn, short orbital horns

ceratopsian frills

-thermal control, display, defense

pachycephalosaurs head butting

-damaged skulls

epioccipital bones

-edge of the frill that fused to the back of the skull

cheeks on marginocephalia

-dental battery convergent with hadrosaurs

undomed, partially domed, & fully domed in some taxa?

-john homer & others noted that dome growth is an ontogeny series
-they grow a bigger dome on their head and grow into their species

marginocephalians in herds

-giant bone bed - flooding event preserved thousands of individuals

why aren't ceratopsians on every continent?

-plate tectonics. north america and asia only were connected

pangaea evidence

-look like they fit together
-can connect ice caps
-related fossils on every continent

plate tectonics

-based on seafloor spreading
-the earth's crust is made of plates
-plates collide and separate
-plates are destroyed and recycled
-ocean floor is relatively young

continental drift

-based on continents
-continents slide along ocean floor
-happens because of earth's rotation & tidal pull
-ocean floor is millions of years old

crust created

-oceanic ridges
-as plates get consumed they separate from each other. as they separate, magma comes up & creates a new crust

crust consumed

-oceanic trenches
-the denser plate goes under the other plate creating a trench. the plate continually goes under until it reaches the mantle & melts

seafloor spreading evidence

-magnetic poles switching
-stripes of differing magnetic poles on the ocean floor

driving force of continental drift

-earth's rotation, tidal pull

driving force of plate tectonics

-magma covection within earth's mantle

rejection of wegener's theory (continental drift)

-ideas of continents plowing through solid rock & ocean was unheard of
-proposed driving forces "implausible"
-he was a meteorologist, not geologist
-he was german
-didn't have evidence

plate tectonics & organisms

-volcanoes
-mountains
-earthquakes
-organisms evolving/not depending on where they end up after shifting
-same fossils on all continents

plate tectonics unifying theory

-explains most geology phenomena & processes

nocturnal dinosaurs

-huge eyes/scleral rings

dinural dinosaurs

-small scleral rings

theropods & feathers

-tail preserved in amber
-could see down feathers
-found feathers in sandstone
-feather attachments found on bones
-big dinos too - yutyrannus

mononykus were probably anteaters

-only had thumb
-forearms
-ulna has long process to give support for tearing into ant mounds
-no teeth, weak jaws, long tongue
-mechanical study

dinosaurs and crocs stacking in china

-big sink pit and dinos would go in looking for food & get stuck

color of feathers

-pigment capsules in feathers
-round = rust color
-pill-shaped = black

evidence of keratinous prjections

dermal ossicles

likely feathered dinos

-theropods
-yutyrannus
-anchiornis
-archaeopteryx

anchiornis

-gliders, not active flyers
-4-winged dinos
-feathers colors, revealed by pigment capsules in feathers
-looks like bacteria, but it is actually pigment capsules

fleas

-10x larger than modern
-22 mm long - almost an inch
-preserved in amber
-stuck in feathers of dinos
-suggests dinos were warmblooded
-40 million years ago

lice

-preserved in amber
-chewed on feathers
-100 million years ago

pterosaurs

-originated in late triassic
-extinct in late cretaceous

pterodactyloid

-nares and antorbital fenestra fused together (mono fenestra)
-no teeth
-short tail

rhamphoryncoid

-have teeth
-nares and antorbital fenestra are separated
-long tails

preservation of pterosaurs

-marine/lacustrine environments

pterosaur bones crushed flat

-delicate pneumatic bones

avemetatarsalian novelty

-ankle goes back & forth, not side to side

walking position of pterosaurs

-quadrupedal when walking
-we know because of tracks

pterosaur wing structure

-wing on 4th digit
-skin membrane stretched betweenbone
-ossified rods to stiffen wings

pterosaur skull crests

-mostly for display and sexual dimorphisms

pterosaurs were endothermic

because of feathers

pterosaur primitive feathers

-hair-like feathers
-also had hair
-down feathers
-aerodynamic, keep warm

permits

protects bones from poachers

CAT scanning

-high resolution
-bones still inside rock
-doesn't destroy specimen if you mess up
-minute detail

mechanical extraction

-mini jackhammer
-needle under microscope
-likely to destroy bone

naming rules

-whoever publishes on it first gets to name it
-genus needs to be unique
-species can be duplicate
-latinized
-cannot be an insult
-usually related to place/person of discovery
-binomial

lumper

-groups genera or species into a single species

splitter

-thinks most things they find are new genera or species