Archosaurs + Crocodilians

archosaur group includes:

dinsoaurs, crocodiles, pterosaurs, birds

What is a major characteristic of archosaurs related to skull structure?

Antorbital fenestra

What shape is the eye socket of archosaurs?

Triangular for support

What type of teeth do archosaurs have?

Laterally compressed teeth that are sharp and serrated

What trend in locomotion is observed in archosaurs?

Bipedalism trend

What feature is found on the femur of archosaurs?

4 trochanter on femur

why are 4 trochanter advantageous

provide extra points for muscle attachement allowing for increased power

Antorbital fenestra

Opening in the skull in front of the orbits that reduces weight

pterosaurs + the periods they lived in

flying archosaurs that lived from late triassic to cretaceous period

What adaptation do pterosaurs have to strengthen their wings?

Short radius and ulna

why are pterosaurs 4th finer elongated

to support a stretched wing membrane

What type of bones do pterosaurs have to decrease weight?

Hollow bones

What feature of pterosaurs strengthens their chest for longer flight duration?

Well developed sternum

What adaptations do pterosaurs have for increased flight coordination?

Large eyes and cerebellum

Cerebellum

brain structure responsible for our balance and coordination

ulna

long, inner forearm bone

Pterosaurs similarities with birds

hollow bones + well developed sternum, reduced olfactory bulb, large eyes + cerebellum

two major dinosaur groups

saurischians and ornithischians

Saurischian pelvic structure

3 point structure where pubis points forwards + down

saurischian 2 major groups

sauropodomorpha + theropods

sauropodomorpha examples

brachiosaurus and plateosaurus

sauropodomorpha

long necked quadrupedal herbivores

sauropodomorpha adaptations

thick vertical ligaments to support neck, high blood pressure, massive bones, small skull, gastroliths

gastroliths

Swallowed stones in the stomach that aid in mechanical digestion

Therapods

carnivorous bipedal saurischians that birds evolved from with backwards 1st toe

therapod examples

t-rex, velociraptor, ornithomimus

Ornithischian pelvic structure

pubis points backwards

3 major ornithischian groups

thyrephora, ornithopods, marginocephalia

Thyreophora examples and key characteristics

stegosaurus + ankylosaurus, bony plates and tail clubs for defence

ornithopods examples

iguanodon + parasaurolophus

ornithopods key characteristics

specialised teeth for chewing, long hind limbs+ short fore limbs, hollow crest

Marginocephalia examples

pachycephalosaurus, triceratops

marginocephalia key characteristics

thick skulls, frills + horns

all ornithischian have what feeding type

herbivory

Phytosaurs

late triassic, crocdilian like with nostrils before eyes and nasal passage to mouth

crocodilian's skull

Elongated and robust diapsid skull

What type of teeth do crocodilians have?

Thecodont teeth (embedded in socket)

What is a unique feature of crocodilian anatomy related to respiration?

Complete secondary palate

what type of heard do crocodilians have?

Four chambered

Foramen of Panizza circulatory system in crocdillians

shunt system redirects blood when diving

4 chambered heart

seperated de/oxygenated blood for efficient O2 circulation

Hot temperatures in crocdilians yields...

males

3 major crocdilian groups

Alligatoidae, crocdylidae, gavialidae