Reptilian characters of archaeopteryx: 1 Jaws are provided with homodont teeth. 2 Long, lizard like tail with 20 free caudal vertebrae. 3 Bones are not pneumatic. 4 Cervical vertebrae are fewer, 5 to 12. 5 Amphicoelus vertebrae as in Sphenodon. 6 Cervical and abdominal ribs are present along with thoracic rib. 7 Sternum weak or absent. 8 Scales are present. 9 Eyes are provided with sclerotic ossicles.
Avian Characters: 1 Presence of feathers. 2 Fore limbs are modified as wings. 3 Rounded brain case. 4 Beaks are present. 5 Bones in the skull are intimately fused. 6 Bird like bones of limbs and girdles. 7 A Keel is present on sternum. 8 Tibia and Fibula are separate.