Differents Types Of Natural Birds

Birds diversified into a wide variety of forms during the Cretaceous Period.[22] Many groups retained primitive characteristics, such as clawed wings and teeth, though the latter were lost independently in a number of bird groups, including modern birds (Neornithes). While the earliest forms, such as Archaeopteryx and Jeholornis, retained the long bony tails of their ancestors,[22] the tails of more advanced birds were shortened with the advent of the pygostyle bone in the clade Pygostylia. In the late Cretaceous, around 95 million years ago, the ancestor of all modern birds also evolved better olfactory senses.