In all examples , the evidence described consists of feather impressions , except those genera inferred to have had feathers based on skeletal or chemical evidence , such as the presence of quill knobs ( the anchor points for wing feathers on the forelimb ) or a pygostyle ( the fused vertebrae at the tail tip which often supports large feathers ) .
The evidence consists of feather impressions , or convincing skeletal or chemical evidence . Skeletal evidence would be the presence of quill knobs ( the anchor points for wing feathers on the forelimb ) or a pygostyle ( the fused vertebrae at the tail tip which often supports large feathers ) .