Dinosaur tail fossil | Archaeopteryx Fossil, most primitive bird known
*Sinocalliopteryx gigas in the Early Cretaceous (122–125 million years ago)
During the Late Cretaceous seen here 90 million years ago the Americas were drifting westward and a large body of water called the Western Interior Seaway divided North America. Huge fish and gigantic reptiles called mosasaurs and plesiosaurs plied the seas. Europe was a chain of islands populated by dwarf dinosaurs and gigantic flying reptiles called pterosaurs. Across the globe on land dinosaurs were ascendant. They exploded in diversity into groups like the tyrannosaurs hadrosaurs…
These fossils found in northeastern China show the diversity and small sizes of some of the feathered dinosaurs. Many avian traits evolved in dinosaurs long before birds themselves appeared. Photograph by Robert Clark, Fossils from the Institute of Vertebrate Paleontology and Paleoanthropology, Beijing; Shandong
Why were dinosaurs covered in a cloak of feathers long before the early bird species Archaeopteryx first attempted flight? Researchers postulate that these ancient reptiles had a highly developed ability to discern color. Their hypothesis: The evolution of feathers made dinosaurs more colorful, which in turn had a profoundly positive impact on communication, the selection of mates and on dinosaurs’ procreation.