If you are knowledgeable in paleontology, could you answer any of my bird/dinosaur questions?

Question

1. Did Archaeopteryx evolve from Epidendrosaurus?

2. Since birds are Maniraptors, the last surviving Coelurosaurs, can we accurately define birds as actual dinosaurs?

3. I've heard that birds and reptiles have a common ancestor. What species is that, and can we also call reptiles dinosaurs?

4. When did the first known feather emerge? That is, when did the feather mutation arise, and which species was it first found in? The Maniraptors were primarily feathered dinosaurs, and my assumption is that Sinosauropteryx was the first of the dinosaurs to have feathers. Does this mean that the first feathers emerged about 123 MYA?

Answer 1

1. Hard to tell. The age of the rocks Epidendrosaurus is found in is contested, it could be either older or younger than Archaeopteryx. They live in pretty different places (China vs Germany) so I'd be more inclined to say they're cousins rather than descendents.

2. Yes, sometimes birds are included within Theropoda, it just depends on who you ask.

3. Birds and reptiles have a common ancestor, but it wasn't any particular species. All life has a common ancestor if you go back far enough. Reptiles are not dinosaurs, they have different anatomical features such as a splayed stance and different hips compared to dinosaurs.

4. I'd say feathers emerged probably in the early Jurassic, around 170 million or more years ago. If most of the Coelosaurs had feathers that suggests that the ancestor of that group already had feathers, which it then passed on to the Coelosaurs. They wouldn't have been feathers as we know them, but proto-feathers. This is the fluffy, barb-less feather bird chicks have today. Over time feathers would have evolved to become stronger and smoother to enable flight, with the flighted Archaeopteryx evolving 150 million years ago. These proto-feathers would've been rarely fossilied, so it's hard to know who evolved them first. Feathers would have evolved over a very long period of time, it wasn't a single mutation that turned a scale into a feather.

Answer 2

1. They couldn't know that even if they were sure it was older.  It is possible but it could be just a relative and not in the direct lineage.

2.  No, but it is semantics.  

3.  There were many species of amphibians that predated reptiles and birds.  

4.  I thought microraptor is the oldest known flight feathers at about up to 130 million years old.  This field changes so fast, it is hard to keep up.  Considering how rare fossils are, I would think the most likely guess, would be about 10 million years older.