The evidence consists of feather impressions, or convincing skeletal or chemical evidence.

Fossil feather impressions are extremely rare and they require exceptional preservation conditions to form.

There are feather impressions preserved on the right hand and also probable tail feathers preserved near the left foot.

The most prominent feather impressions trail from the left forearm and hand.

The tail was relatively long and feather impressions were found near the tip.

Additional feather impressions were identified along the neck.

The specimen consists of a slab and counterslab, mainly showing a torso with some feather impressions, lacking both head and tail.

The single known species Concornis lacustris was described from remains of one individual skeleton which is not quite complete but bears feather impressions.

In this case one farmer found a rare fossil of a toothed bird, complete with feather impressions.

When a perfect specimen of Sinornithosaurus, complete with feather impressions was found, it was a turning point in the study of dinosaurs.