The first birds had sharp teeth, long bony tails, and claws on their hands. The clear distinctions between modern birds and other animals did not exist in early birds.
In fact, the earliest birds resembled small dinosaurs more than any birds today.
The earliest known bird (based on fossils) is Archaeopteryx, which lived 150 million years ago, but birds had already evolved before that. Shortly after Archaeopteryx, a series of birds with more advanced characteristics appeared. One group gave rise to modern birds in the Late Cretaceous. Thus, for a time, bird-like dinosaurs, primitive birds, and early modern birds coexisted.
Two examples of the early bird are:
Lithograph Archaeopteryx
Archaeopteryx possessed many characteristics not found in modern birds, including:
1. A chin with teeth
2. It has claws on its hands.
3. A long, bony tail
Confucius
Confuciusornis is an early bird that lived in China 125 million years ago. It possessed many primitive features, including claws on its wings. However, it had more advanced features than Archaeopteryx, as it is one of the earliest known birds to have a shortened bony tail and a toothless beak. It also had feathers adapted for flight. Melanoid studies of Confuciusornis fossils show that it had dark feathers on its body and dark and white feathers on its wings.
