Feathered dinosaur 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 similar to those of birds, which suggests that they evolved from common ancestral genes. Shortly after the 1859 publication of Charles Darwin's "On the Origin of Species", British biologist Thomas Henry Huxley proposed that birds were descendants of dinosaurs. He compared the skeletal structure of "Compsognathus", a small theropod dinosaur, and the 'first bird' "Archaeopteryx lithographica" (both of which were found in the Upper Jurassic Bavarian limestone of Solnhofen). He showed that, apart from its
Specimens of Archaeopteryx Tischlinger & Unwin (2004), who reclassified it as part of the sternum, albeit minimally ossified (mostly cartilagenous). This supports the idea that the Berlin "Archaeopteryx" was not a full-grown individual at the time of its death, and instead represents an immature animal. The pelvis of the Berlin specimen was considered by Dames to be markedly different from that of the London specimen, which was a major point in favor of his assigning a new species to the Berlin "Archaeopteryx", "siemensii", after its generous donor. Other researchers, however, disputed this difference, claiming it could be entirely accounted for by deformation of