outgroup: tunicates, cephalochordates

synapomorphy: cranium

outgroup: myxinoidea - hagfish

synapomporphy: vertebral column, vertebral elements

outgroup: petromyzontoidea - lamprey

synapomporphy: jaws formed from mandibular arch, paired limbs, notochord presistent or replaced by vertebral center

outgroup: chondrichthyes - cartilaginous fish

synapomorphy: presence of lung or swimbladder derived from gut

outgroup: actinopterygii - bony fish/ ray-finned fish

synapomorphy: unique supporting skeleton in fins

outgroup: actinista - lobe-finned fish (coelacanths)

synapomorphy: teeth formed from dentine

outgroup: dipnoi - lungfish

synapomorphy: limbs with carpals, tarsals and digits

outgroup: lissamphibia

synapomorphy: shelled egg with three membranes, amnion, chorion, allantois.

outgroup: gymnophiona - caecilians

consists of anura and urodela

division of amniotes opposite sauropsida

synapomorphy: only a lower temporal fenestra present

outgroup: monotremes

synapomorphy: loss of coracoid bone... etc

outgroup: testudinata (turtles)

synapomorphy: skull with both dorsal and ventral openings

outgroup: lepidosauria (snakes, lizards and tuatara)

synapomorphy: presence of fenestra anterior to eye orbit.

Division of amniotes opposite to synapsids

synapomorphy: tabular and supratemporal ones small or absent, beta keratin present