Dinosaur renaissance "reptiles" and birds. Shortly after the 1859 publication of Charles Darwin's "The Origin of Species", British biologist and evolution-defender Thomas Henry Huxley proposed that birds were descendants of dinosaurs. He cited skeletal similarities, particularly among dinosaurs, the "first bird"—"Archaeopteryx"—and modern birds. However, in 1926, Gerhard Heilmann wrote his influential book "The Origin of Birds", in which he dismissed the dinosaur–bird link, based on the dinosaurs' supposed lack of a furcula. Thereafter, the accepted hypothesis was that birds evolved from crocodylomorph and thecodont ancestors, rather than from dinosaurs. This removed dinosaurs from a central role in debates about the origin of
Specimens of Archaeopteryx its aerodynamic function as a flight feather. As the feather bears little resemblance to the retrices of the other full "Archaeopteryx" skeletons, it is generally thought to be a wing feather: Griffiths and others have concluded it was a remex, while Carney in 2012 interpreted it to be a covert feather. The feather has a relatively low degree of asymmetry, which Speakman and Thompson in 1994 concluded to indicate it as a secondary remex. If this is the case, then it would have originated from an animal smaller than even the Eichstätt specimen, which is the smallest "Archaeopteryx" specimen known