Archaeopteryx fossils show that the animal had feathers like a bird. it also had a bony tail, teeth, and claws on its wings like a reptile. scientists claim this is evidence of a common ancestor. what makes this a sound claim? birds and reptiles are warm-blooded organisms. archaeopteryx fossils share traits with both birds and reptiles. reptile species show evolutionary advantages over birds. fossils of birds, archaeopteryx, and reptiles were found together.