planar feathers w/ asymmetrically-positioned shafts, keeled sternum, pygostyle (reduced tail),
toothless opposable big
toe, modified shoulder for upstroke, tarsometatarus (bone used for maneuverability), alula (feather used to break turbulence),
carpometacarpus (fused wrist and hand used to reduce flexion), furcula (wishbone), hollow air-filled bones. Birds closely related to
dromaeosaurs (raptors). Oldest bird dated back to late Jurassic found in Germany:
Characteristics: Bird- expanded
braincase, asymmetric feathers, keeled sternum, pneumatic bones. Dinosaurs- teeth, 3 fingers w/ claw, long tail, raptor-like pelvis.
Feathers on Dinosaurs
: Not symmetrical (not able to help in flight. Lack of feathers and short arms also proves not used to fly). Used
for insulation, display, insect-catching, increased speed/lift.
Evidence used against raptor descendancy:
dinos w/ feathers are flightless
birds that evolve into dino characteristics, 1
true feathers appear in late Triassic along with 1
real bird, archaeopteryx appears
Jurassic; raptors appear cretaceous.
last common ancestor of
and living birds
(flight), keeled sternum, pneumatic bones, opposable big toe?
pygostyle, large corocoid bone
between arm and sternum
two groups with the following
carpometacarpus, flexible wishbone- furcula,
modified backstroke shoulder
dominant birds of Mesozoic
full backward rotation of pubis,
(also called Neornithes): modern birds, dominant after the K-T extinction,