March 19, 2014 | David F. Coppedge

Imaginary Feathers Found on American Dinosaur

Once again, imaginary feathers have been discovered on a “bird-like” dinosaur, this time from the Dakotas.

The fossil was discovered about a decade ago, but is only now being described.  Artwork shows feathered arms and fuzz on the body and legs of the ten-foot “chicken from hell,” Anzu wylieli.  Science reporters describe the imaginary feathers in detail:

  • It boasted a flashy head crest and probably wore feathers. (Live Science)
  • It was a giant raptor, but with a chicken-like head and presumably feathers. (PhysOrg)
  • The size of a small car, the dinosaur also had claws and feathers on its upper arms. (BBC News)
  • Although the Anzu specimens preserve only bones, close relatives of this dinosaur have been found with fossilized feathers, strongly suggesting that the new creature was feathered too. (Science Daily)
  • The 66-million-year-old feathered dino resembled a demonic cassowary. (National Geographic)
  • In addition to its long limbs, the team found the ancient animal sported a stubby tail, likely framed by a fan of tail feathers. Though the team didn’t find direct evidence of feathers, the species was so closely related to birds that it was very likely covered in feathers that looked identical to those of modern birds. No one knows why the dino needed feathers-courtship displays and insulation are two theories—but the scientists do know its environment was hot. (National Geographic)
  • The first, Anzu, translates to mean “Mesopotamian feathered demon.”  The new fossils were not found with feathers, Schachner said, but the dinosaur’s close relatives had them, and it’s highly likely Anzu wylieli did, too.  (Live Science)
  • With its head crest and presumably feathered forelegs, the newly discovered and described dinosaur Anzu wyliei was nicknamed the “chicken from hell” by its discoverers at the Carnegie Museum of Natural History…. (PhysOrg)

Live Science admits this creature comes from “an enigmatic group of dinosaurs” that are “not really well-known” other than the certainty about their imaginary feathers (see 6/13/07, 7/09/08, 9/20/11, 5/03/13).

The original paper in PLoS ONE, like the popular media, calls it a “presumably feathered dinosaur” but otherwise includes no evidence of feathers. “Most if not all oviraptorosaurs were feathered,” the paper says, citing “direct preservation”, “possible quill knobs” (9/09/10) and “pygostyle-like terminal caudal vertebrae” (pygostyle means the bone at the end of the tail, made of fused vertebrae—not feathers).  After “direct preservation” the quote cites 3 papers that mention the Chinese fossils Protarcheopteryx, Caudipteryx, and Similicaudipteryx, discussed elsewhere (use search bar) as possibly secondarily flightless birds.

Just today, though, Nature published an analysis of melanosomes from scales and feathers from creatures as diverse as mammals, birds, dinosaurs, pterosaurs, lizards and turtles.  The researchers, mostly from China, noted a distinct break between the melanosomes of reptiles and those of birds.   Considering that “When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated,” they were rather surprised at what they found:

We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur ‘protofeathers’ and pterosaur ‘pycnofibres’), show a limited diversity of form that is uncorrelated with colour in extant taxa.

Another article on PhysOrg, though, questions whether colors can be deduced from melanosomes.  Researchers at North Carolina State believe “it is not yet possible to tell if these structures – thought to be melanosomes – are what they seem, or if they are merely the remnants of ancient bacteria.”

In order to keep the story of feather evolution going, Nature offered the following speculation:

These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.

Other than that, there was no further mention of evolution.  True pinnate feathers (as on birds), it should be noted, are not mere “novel integumentary structures,” but distinct systems involving follicles, stem cells, and regulatory proteins.  It must have taken a “significant physiological shift” to evolve them, indeed.

Imagining is like lying.  Once you get started, it’s hard to stop, and each subsequent instance has to get more emphatic to keep the tale going.


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