Intro to Dinosaurs Exam 2

euparkeria is a what?

archosauriformes

what are the 4 synapomorphies of archosauriformes?

mandibular fenestra, antorbital fenestra, symmetrical foot, serrated teeth in sockets

Crurotarsi

crocodilian lineage that's an archosauria

3 synapomorphies of archosauria

build complex nests and protect young, 4 chambered heart, supraacetabular crest

ornithodira has what?

plerosauria

dinosauromorpha has what

silesauridae

dinosaumorpha has what synapomorphy

s shaped neck

dinosauria has what

saurischia

what are the 4 synapomorphies of dinosauria

feathers, opposable thumbs, sharply in-turned femoral head, perforated acetabulum

ornithischia has what

heterodontosauridae

what is unique to heterodontosauridae

tusks

what are the 5 synapomorphies of ornithischia

predentary bone, back-turned pubis, in-set jaw margins, ossified tendons, blunt teeth BIPED HERBIVORES

genasauria has what

thyreophora

thyreophora has what unique trait

osteoderms

what group does lesothosaurus belong to

thyreophora

what group does scutellosaurus belong to

thyreophora

what group does stegosauria belong to

thyreophora

what 2 synapomorphies are unique to stegosauria

two rows along midline of back, thagomizer

what group is ankylosauria part of

thyreophora

what two clades branch off of ankylosauria

ankylosauridae and nodosauridae

what synapomorphy defines ankylosauria

broad network covering head, neck, back, hips, tail

what is unique to ankylosauridae

tail club- made of osteoderms and fused caudal vertebrae

what is unique to nodosauridae

sacral shield

cerapoda branches off to what

ornithopoda

ornithopoda branches off to what 4 species

dryosaurus, canptosaurus, iguanodontids, hodrosauridae

what is unique to cerapoda

uneven distribution of enamel on teeth

what is unique to ornithopoda

hinge between maxilla and rest of skull for cranial kinesis

what is unique to hodrosauridae

tooth battery

what is unique to marginocephalia

shelf of bone on posterior skull

what branches off from marginocephalia

pachycephalosauridae

what 2 synapomorphies make up pachycephalosauridae

thickened dome/plate on top of skull, occipital condyle underneath skull

what is the last genus?

ceratopsia

what synapomorphy is unique to the ceratopsia

rostral bone

what animal was not equipped with an offensive weapon

nodosauridae

how did hadrosauridae survive without osteoderms

large herds

why are mid line osteoderms not used for defense

sides of body not protected, not all stegosaurs had broad plates, would've bled if bitten

4 osteoderms at end of tail is called what

thagomizer

why are elaborate frills not used for defense

fragile and often not solid

why are ankylosaurs difficult to study

covered in osteoderms

why are elaborate crests in hadrosaurids not used for defense

hollow and fragile

what synapomorphies indicate that pachycephalosaurs may have used their heads as offensive weapons

occipital condyle underneath skull and thick dome/plate on top of skull

how do we know ceratopsians used their horns for intraspecific(own species) fighting

wounds on faces

why do we think ornithischians had muscular cheeks

inset jaw margins and some ankylosaurs had osteoderms on cheeks

how is a dinosaur thumb different than our thumbs

in the opposable thumb of dinosaurs, most of the movement is between the metacarpal and first phalanx. ours is between carpals and metacarpals

what is ghost lineage

when one group appears in the fossil records after its sister taxon

why do ornithischians have back turned pubis

more room for guts

how is the pelvis of a dinosaur different from other other archosaurs

dinosaur acetabulum is a hole not a solid cup

vicariance vs dispersal

.Dispersal occurs when a few members of a species move to a new geographical area, while vicariance occurs when a natural situation arises to physically divide organisms.

WHY ARE PLATE TECTONICS IMPORTANT FOR HISTORICAL BIOGEOGRAPHY

controls formation and distribution of geographic barriers, land masses, oceans and sea level

what is historical biogeography

the spatial distribution of organisms on earth in the past

what is the principle of parsimony

when given multiple explanations for a problem the simplest/fewest steps is preferred

vicariance (preferred)

division of a population by geographic barriers. cant happen if regions were never connected or timing doesnt match

dispersal

extension of a population's range across a geographic barrier

ganglia

nerves come together and shoot off along the vertebral column

what dino has spikes on hands

iguanodon

horns and frills are used for

sexual display species recognition jousting each other

saurischia pelvis lizard hip

V for running illium ischium pubis

ornithischia pelvis bird hip

ischium and pubis are touching facing backwards

pterosauria

flying reptiles that aren't birds

only characteristic that diagnoses dinos is

perforate acetabulum (hole)

carnian stage

oldest fossils found

carnian pluvial episode

climate change that caused non dino extinxtion and rise of dinos

what characterizes thyreophora

parallel rows of osterderms

nodosauridae are FORTRESS

more lightly built ankylosaurs (THYREOPHORA)

ankylosauridae FORTRESS

tail club

Eurypoda

dumb

marginocephalia

ridge of bone across back of skull

pachylo

bipedal flat and dome headed

ceratopsia

quadroped

ornithopoda

bird foot iguanodon

LAG is what

line of arrested growth

endothermic metabolsm

4 chambered heart high EQ haversian canals erect stance

euparkaria

walking lizard insect eater