12 synapomorphies for lissamphibia
1. Pedicellate and bicuspid teeth. teeth have two sides/ cusps one of each side of the mouth (ligual, and labial)
2. The middle ear is made up of two parts. The collumela or stapes, and the operculum. Which is not homologous to the one in fish. The operculum is connected to the scapula via the opercular muscle. This allows the organism to hear ground vibrations.(opercular apparatus is lost in caecillians)
3. The stapes is directed dorsolaterally from the fenestra ovalis.
4. The fat bodies develop from the germinal ridge.
5. The skin contains both mucus and poison glands that are very similar in structure.
6. Specialized receptor cells in the retina of the eye called green rods. Except caecillians lac them.
7. A sheet of muscle called the levator bulbi is under the eye allowing the to raise their eyes
8. Cutaneous and bucophanyngeal respiration.
9. Short straight ribs and do not encircle the body
10. Two occipital condyles at the base of the skull
11. Radius and ulna articulate with the humerus at a single point called the radial condyle.
12. Share fenestration patterns and loss in skull bones with Paleozoic tetrapod’s.