Archosaurs and Pterosaurs Flashcards
what is included in archosauria?
pterosauria
crododylomorpha
dinosaur/aves
what are the synapomorphies (common features) between the archosauria
antorbial (lost in crocodiles) and mandibular fenestra
what are the common traits of archosauria
- reduction of 5th digit on the hind limb
- presence of gastroliths in the stomach
- unidirectional air flow
- 4 chambered heart
- pneumatized bones
what are the characteristics of basal examples of pterosaurs?
- bipedal
- very small
- lived in trees
- enlarged balance brain region
why are the new animals after an extinction always smaller?
there are limited resources so they would need less
what are the defining features of pterosaurs
- pteroid bone (no other creature has it)
medially directed inward facing bone that supports one of the patagium - patagium dived into 2 to 3 sections
- synsacrum
- pycnofibers
- keratinous beaks
- front digits pointed caudally
what other living creatures have patgiums?
bats and flying squrriels
what are some characteristics of pterodatyloid pterosaurs
- small tail
- larger
- great flying ability
- most likely parental care
what are some characteristics of non pterodatyloid pterosaurs
- long tails used ruder
- small
- wings more for gliding
what is the main difference between pterodatyloid pterosaurs and non pterodatyloid pterosaurs
pterodatyliods have more variety in crest and beak shape for feeding
what is pycnofibers?
they MAY be ancestral feathers
- short non branching and branching fibers
- assumed to be for warmth
how do pycnofibers work?
they were coloured assuming to be for sexual selections
why is there many types of beaks?
for the various types of diet
