It is a primitive fossil bird which lives in the late Jurassic period about 140 million years ago. Its fossils were discovered in 1861 from Germany. Its scientific name is Archaeopteryx Lithographica. This animal in many aspects is an interesting combination of reptilian and avian features. So in the strict area, it is neither a true reptile, nor a true bird but is intermediate between reptiles and birds.

It is a connecting link that bridges the evolutionary gap between reptiles and birds. Its reptilian features reveal that birds evolved from arboreal, bipedal reptiles. It provides information on possible course of avian evolution and reveals that birds are glorifies reptiles.

REPTILIAN FEATURES

• Toothed jaws, with peg like homodont and thecodont teeth.

• Non-pneumatic bones.

• Long, terminally tapering tail, supported by free posteriorly tapering caudal vertebrae as in lizards.

• Amphicoelous vertebral centra, as in sphenodon.

• Lack of fusion of trunk, sacral, and caudal vertebrae.

• Absence of phagostyle.

• Presence of free cervical and abdominal ribs, as in sphenodon and crocodilians.

• Absence of mandibular foramen, as in crocodiles.

• Clawed digits and free carpels and metacarpals, without carpometacarpus.

• Reptilian number of phalanges in the fore – limb.

• Small, poorly developed and keel less sternum.

• Elongated and backwardly directed pubis.’

• Small cerebellum.

AVIAN FEATURES

• Presence of contour feathers over the body, remiges on fore limb and rectrices on tail.

• Forelimb id modified as a wing with three fingers.

• Elongated hind limb, with four clawed digits.

• Backwardly directed hallux.

• Avian number of phalanges in the hind – limb.

• Presence of tarsometatarsus in the foot.

• ‘V’- shaped furcula in the pectoral girdle.

• Large skull, with rounded cranium, large orbits and fusion of skull bones.

• Elongated jaws, forming beak.

• Scleratic plates and pectin in eyes.

• Warm bloodedness.

Archaeopteryx is believed to be an arboreal forest dweller, climbing on trees with the help of its clawed fingers and perching on branches by means of opposable great toe probably, it had limited powers to flutter, to glide from branch to branch, or to soar for small distance, with its tail serving as a parachute.