Download - Archosaurs
ARCHOSAURS
Dominant land vertebrates during the Mesozoic
Display a trend towards bipedalism – 2 footed locomotion
Forelimbs tend to be reduced and hindlimbs are drawn under the body to become the major weight bearing and locomotor appendages
Skull is diapsidThere is an additional fenestra – antorbital fenestra – large mandibular foramen opening in the skull in front of the eye that distinguishes archosaurs
THECODONT
Gave rise to all later archosaurs Named because their teeth are set in deep
sockets Stem archosaurs
PTEROSAURIAThe Winged Reptile
PTEROSAURS!
More commonly known as PTERODACTYLS
First vertebrate to evolve powered flight
ACTIVE AERIAL LOCOMOTIONPterosaurs, birds and bats
RHAMPHORHYNCHOIDSLong tails and teeth
LATER PTERODACTYLOIDS Lacked a tail and teeth. Had projecting crest
at the back of the head.
TWO TEMPORAL FOSSAE/POST ORBITAL FENESTRAE
I BELIEVE I CAN FLY
Like birds, Pterosaurs had pneumatic bones
Wings were more bat-likeSupported by an elongated 4th finger
Long, hollow bonesConvergent evolution
DINOSAURSRAAWRRR!
DINOSAURS!One of the most successful groups of
animals (in terms of longevity) that have ever lived, evolved into many diverse sizes and shapes, with many equally diverse modes of living.
Contains two major groups of dinosaurs: the Ornithischia, or "bird-hipped" dinosaurs, and the Saurischia, or "lizard-hipped" dinosaurs.
SAURISCHIAReptilian pelvisSwift predatory carnivoresThe three bones of the pelvis – ilium, ischium, pubis– radiate outward from the center of the pelvis
ORNITHISCHIANSPelvis similar of that of birdsHerbivores. Lack teethSome had horny beaksSome small unidentified bipedal
ornithischian is thought to have given rise to birds
The ischium and part of the pubis lie parallel and project backward toward the tail