What dinosaurs are possible transitional species between reptiles and birds?

Question

What dinosaurs are possible transitional species between reptiles and birds?

Answer 1

When you say "possible", you leave the field wide open. If you were to Google "feathered dinosaur" the first thing you'd likely see would be Archaeopterx, but there were many more. Even T-Rex would possibly be a transitional species!

Answer 2

the raptor

Answer 3

there are a lot of genera and species which fit into this broad question, but if I were you, I'd do some research on some of the feathered dinosaurs coming out of the Liaoning province in China.

Answer 4

Maniraptors.  A particularly fine display is provided by the feathered and four winged dromaeosaurid named /Microraptor gui/.  It's too late to be a candidate as a bird ancestor itself, but it makes a good case for the possible involvement of earlier members of its family, Dromaeosauridae.  Dromies are known to have been around during the Upper Jurassic as well as the Cretaceous.

And then, of course, the retention of non-avian characteristics of /Archaeopteryx/ should be taken into account.  Its fine non-bird tail is easily recognisable from the ever so many pictures freely available on line.  Bird tails are reduced to a few vertebrae that are fused together into a rather unflexible rod.  Archie's tail is a fine, mobile thing composed of over twenty individual bones.  I forget the exact number of hand, but it's most unbirdlike.