Rise Of The Archosaurs Flashcards
What does the Mesozoic era refer to?
Triassic
Jurassic
Cretaceous
What does archosaurs literally mean
Ruling reptiles
When did the Archosaurs dominate and what did they take over from?
Clade of diapsids that’s dominated terrestrial environments of the Mesozoic, taking over from the synapsids that had dominated the Palaezoic
What were the Mesozoic oceans dominated by? (Marina diapsids)
PIMM
Icthyosaurs
Plesiosaurs
Marine turtles
Mosasaurs
What did archosaurs dominate?
Terrestrial areas
What was the most specialised marina diapsids?
Icthyosaurs
What have all marine diapsids done?
All evolved more active lifestyles in the ocean in response to predatory behaviour
X
4 chambered heart
X
More erect gait
Modified ankle joint with calcaneal tuber
What are pterosaurs highly specialised for
flight
What feature do diapsids have?
Amniote tetrapods with two holes (temporal fenestra) in their skull
What feature do synapsids have?
One hole (fenestra) behind each eye orbit on the lower part of the skull
Anapsids
No openings in the skull
What does the temporal fenestra (diapsids) allow?
Allows the expansion of jaw musculature beyond the adductor chamber
What does the temporal fenestra (diapsids) accommodate? (3)
Larger muscles
Teeth
Powerful bite
What are the two openings of the temporal fenestra called?
Mandibular fenestra
Antorbital fenestra
What type of ankle do archosaurs have?
Modified ankle joint with calcaneal tuber
What is the modified ankle of archosaurs associated with?
A more erect gait
Semi-bipedalism
How do Mesozoic crocodylomorphs differ from modern, living crocodiles?
Much greater diversity
What are pterosaurs (an order of reptiles) highly specialised for?
Flight
Why are pterosaurs not dinosaurs?
X
How is a pterosaur wing formed?
Skin membrane stretched between hyper elongates 4th finger of forelimb, and ankle area of hindlimb
What are the largest animals ever to fly?
Pterosaurs
How do pterosaurs walk?
Quadrupedally Plantigrade hindlimb (flat footed) and digitigrade forelimb (walking on fingers to accommodate wing)
