dinosaurs exam 2 review

saurischians

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