File:Pinguinus Alfrednewtoni (fossil Auk Leg Bone).jpg
However, birds are evolutionarily derived from theropod dinosaurs. Birds first appeared in the Triassic or Jurassic, depending on which avian paleontologist you ask. They inhabit a wide variety of terrestrial and surface marine environments, and exhibit considerable variation in behaviors and diets.
The fossil bird leg bone shown here belonged to Pinguinus alfrednewtoni, an ancient, extinct relative of the great auk, which was a Holocene species.
Classification: Animalia, Chordata, Vertebrata, Aves, Charadriiformes, Alcidae or Panalcidae
Locality: quarry north of Aurora, eastern North Carolina, USA
See info. on the great auk:
en.wikipedia.org/key/Great_auk