1. Fossilized Archaeopteryx lithographica was discovered in 1861 from Bavari,
Germany. It belonged to Jurassic period about 140 million years ago.
2. Body was divisible into head, neck, back breast, abdomen and tail. Tail
elongated.
3. Head contained the eye, nostril and toothed beak. Head, neck and beak like birds.
4. Forelimbs modified into feathers or wings. Wing feathers consisted of remiges while tail feathers were made up of retrices.
5. Whole body was covered with scales .
6. Hind limb consisted of tarsometatarsus, hallux and clawed toes.
7. Above fossil possessed both reptilian and avian characters.
8. Reptilian features - Epidermal scales over body, Simple brain, Cylindrical
cerebral hemispheres and unexpanded cerebellum, Jaws with peg like homodont
teeth is sockets, vertebral amphicoelus, sternum poorly developed without keel, Cervical vertebrae 9-10 and caudal vertebrae 20.
9. Avian characters - Presence of feathers, Jaws like beak, Skull monocondylic, Girdles and bones avian, Scapula elongated and curved, Clavicles fused into V- shaped furcula, Foot consisted of tarsometatarsus, Hallux opposable and, Sclerotic ossicles are present in the eye.
Special features : Archaeopteryx is excellent example of connecting link
between reptiles and birds. It gives definite examples regarding the origin of birds.
Source:
1. Practical Zoology Vertebrates by S.S.Lal. 2. A Manual of Practical Zoology Chordates by Dr. P.S. Verma.
