![]() ![]() It is entirely possible that even the terrifying Tyrannosaurus had plumage during at least some stage of its life, perhaps to regulate body temperature when small but shedding the feathers as it quickly became larger, and even the recently described Jurassic tyrannosauroid Guanlong (Xu et al 2006) may have had feathers. If these dinosaurs had feathers it raises the question of whether other coelurosaurs, which include the ostrich-like ornithomimosaurs and the tyrannosaurs, also had feathers. ![]() While they are theropods relatively closely related to the raptors therizinosauroid dinosaurs are also very different, having long necks, huge claws on their hands, and perhaps a herbivorous diet. (For a fairly recent reviews see Norell & Xu 2005 and Zhou 2004.) Even more surprising, however, was the discovery of Beipiaosaurus inexpectus, a therizinosauroid dinosaur with integumentary feathers. Specimens like “Dave” (a probable Sinornithosaurus, Ji et al 2001, the first specimen of Sinornithosaurus millenii also bearing filamentous feathers ) threw greater weight to the notion that birds had evolved from predatory dinosaurs. Although there was some skepticism about whether or not the preserved structures were really feathers (Unwin 1998, Thomas & Garner 1998) a flood of feathered dinosaurs coming out of China soon followed and overwhelmingly supported the notion that birds evolved from dinosaurs. Enter Sinosauropteryx prima, described in 1996 (Chen et al 1998). ![]() ![]() Eventually the morphological problems that faced the dinosaur hypothesis, like the supposed absence of clavicles, were overcome with new evidence and increased study but more than Archaeopteryx was needed to confirm the predictions being made. Archaeopteryx was considered to be a bird, too derived to be comfortably called a feathered dinosaur, and while it became increasingly important as a transitional fossil a transition from what was debated. Still, it wasn’t until the second Dinosaur Renaissance of the late 20th century that the notion of birds as living dinosaurs began to hatch.Ī particular problem plagued the hypothesis that birds evolved from dinosaurs, however no feathered dinosaurs had been found. The smaller dinosaurs like Compsognathus and Hypsilophodon were particularly important as they were considered to be more representative of the form of bird ancestors, flightless birds like rheas and emus being the next step in the hypothetical evolutionary system. (It should be noted, though, that similarity was not always considered to reflect an ancestor-descendant relationship.) Even though the term “dinosaur” had only just been coined by Richard Owen in 1842 by the 1870’s the Solnhofen fossils, trackways, and the bipedal Hadrosaurus and Dryptosaurus spurred the first Dinosaur Renaissance, revealing bipedal (and even bird-like) animals rather than the pachyderm-like creatures Owen brought to life at the Crystal Palace. The notion that birds and dinosaurs are closely related has been around for a very long time, kicked off by the discovery of Archaeopteryx and Compsognathus in the mid-19th century and popularized by T.H. As I learned more, however, I came around to the notion that any Deinonychus or Velociraptor that appears without feathers is a naked dinosaur, a growing body of evidence showing that there were probably many more feathered dinosaurs than had previously been suspected. Even after I started taking a greater interest in paleontology I still had problems with reconstructions of feathered dromeosaurs when no specimens with feathers had yet been found. Most of the books I had seen didn’t explain it beyond “These dinosaurs were closely related to birds,” something I didn’t dispute but was not enough to make me feel comfortable with feathered raptors. Seeing fuzzy Deinonychus or some other dromeosaur with a splash of plumage never looked quite right and I didn’t understand why in the course of a few years predatory dinosaurs went from being scaly to being covered in down. For a long time feathered dinosaurs just looked weird to me. ![]()
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