Maybe some dinos came from birds...and not the other way around.

[bryce]

New research/evidence suggest that birds may NOT be descended from dinosaurs after all...but that birds and dinos share a close common ancestor - and that some animals we think of as dinosaurs, such as Velociraptor - indeed all the raptors (which, ironically, means "bird") are actually large flightless birds...

But this is all still very new and has to be worked out and proven...

http://www.sciencedaily.com/releases/2010/02/100209183335.htm

 

[PlixTixiplik]

The news article conflates two issues: the evolution of birds and the evolution of flight.

It is extremely likely that large dromaeosaurs (like Velociraptor) and troodontids evolved from flying ancestors. Basal members of all three groups (dromaeosaurs, troodontids, and birds) were small, four-winged animals that were probably capable of crude flight (there is a more recent discovery of a basal four-winged troodontid called Anchiornis). So the larger raptors were basically the ostriches of the Cretaceous.

However, that doesn't mean that they are birds - it just means that flight evolved before birds did. Birds (Avialae) is defined as the clade including the common ancestor of Archaeopteryx and modern birds, and all of its decendants. No non-avian dinosaur ever clusters within Avialae in phylogenetic analyses, regardless of how bird-like its ecology is.

 

[bryce]

^Wow, thanks PlixTixiplik!


So...flight evolved independently several times among the dinosaur-ish creatures...!?

 

[PlixTixiplik]

That's possible, although right now I think the best we can say is that flight was probably ancestral to the group called Paraves on the family tree above. It's not clear how well they could fly, since they lacked the large keeled breastbone, didn't have a fused bird-like tail, and didn't have this little finger bone called an alula (important for low-speed flight performance, during take-off and landing). But they could at least glide fairly well, as the article says.

 

[Lindley]

That's possible, although right now I think the best we can say is that flight was probably ancestral to the group called Paraves on the family tree above. It's not clear how well they could fly, since they lacked the large keeled breastbone, didn't have a fused bird-like tail, and didn't have this little finger bone called an alula (important for low-speed flight performance, during take-off and landing). But they could at least glide fairly well, as the article says.

Sounds like an early ancestor of the Cessna.