Archeopteryx appeared 14.7 million years ago. It has features of both bird and reptile classes. Its features are-
- Reptilian traits
(i) Archeopteryx 20 vertebrae long like reptiles.
(ii) Their bones are thick and heavy.
(iii) They have teeth in their jaws.
(iv) Their bodies consist of dry scales.
(v) They have claws on their wings.
- Characteristics of birds
(i) Body structure of Archeopteryx is similar to bird.
(ii) Their bone structure is similar to that of birds.
(iii) They have wings like birds.
(iv) Their bodies have bird-like tails and feathers.
(v) Their lips have turned into bird-like beaks.
The characteristics of Archeopteryx show that it has characteristics of the Reptilia and Avis classes. Archeopteryx is therefore said to be the link connecting the two classes.