Feathered dinosaurs

A feathered dinosaur is any species of dinosaur possessing feathers. For over 150 years, since scientific research began on dinosaurs in the early 1800s, dinosaurs were generally believed to be related to the reptile family; the word "dinosaur", coined in 1842 by paleontologist Richard Owen, comes from the Greek for "formidable lizard". This view began to shift during the so-called dinosaur renaissance in scientific research in the late 1960s, and by the mid-1990s significant evidence had emerged that dinosaurs are much more closely related to birds. In fact, birds are now believed to have descended directly from the theropod group of dinosaurs, and are thus classified as dinosaurs themselves, meaning that any modern bird can be considered a feathered dinosaur, since all modern birds possess feathers (with the exception of a few artificially selected chickens).

Among extinct dinosaurs, feathers or feather-like integument have been discovered on dozens of genera via both direct and indirect fossil evidence. The vast majority of feather discoveries have been for coelurosaurian theropods. However, integument has also been discovered on at least three ornithischians, raising the likelihood that proto-feathers were also present in earlier dinosaurs. In 2017, Baron, Norman, and Barrett (2017) proposed that feathers or feather like structures may have originated with the common ancestor of the Ornithoscelida, a group of dinosaurs which includes both theropods and ornithischians, the only two dinosaurian clades in which feathers have been observed so far. It is possible that feathers first developed in an even earlier group, in light of the discovery of pycnofibers of pterosaurs. Crocodilians also possess beta keratin very similar to those of birds, which suggests that they evolved from a common ancestral gene.

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