You can start by googling Protoavis.
This one is from an article on archaeopteryx that can be found on creation.com:
A bird which is unquestionabiy a true bird has been found which dates (by the evolutionists’ own methods) at some 60 million years older than Archaeopteryx. This was announced in Science-News 112:198, Sep. 1977) The find was assessed as above by Dr. James Jensen of Brigham Young University. The article also quotes Prof. John Ostrom of Yale:
‘… we must now look for the ancestors of flying birds in a period of time much older than that in which Archaeopteryx lived.’
An attack on creation.com won’t help you here..... they are not the original source.
Apply the meaning to “Protoavis”.
If the structures on the one known fossil of Protoavis are in fact quill knobs, it pushes the origin of feathers back a long ways before Archeopteryx.
But Archeopteryx need not be the originator of feathers (and chances are it was most certainly NOT) for it to be a species that combines traits of dinosaurs and birds such that it was a feathered flying dinosaur instead of a feathered flying dinosaur that was going to give rise to modern birds.