It’s been know for years that some smaller dinosaurs were feathered. And more feathers have been found on larger dinosaurs.
But were all dinosaurs necessarily feathered? That’s the gist behind the complaining in this story from New Scientist
Is it really the consensus of paleontologists that all dinosaurs were feathered? What’s the status of feathers re: dinos?
It’s pretty unlikely that all dinosaurs were feathered. What’s positively known is that small carnivores like the iconic Velociraptor were definitely feathered. That doesn’t mean they were completely covered in feathers–they may have had patches of exposed skin, or even lots of exposed skin with only some feathers. But they definitely had large arm feathers big enough to leave quill scars on the arm bones.
We do have skin impressions for lots of different dinosaur types, and for most types of dinosaurs there’s no indication of feathers, just scales. But even if they were covered in scales they could have had some feather or feather-like decorations. Even the Tyrannosaur skin we’ve found has only scales, no feathers. That doesn’t change my theory that Tyrannosaurs were covered in fluffy yellow down like a baby duck. I call it the “Tyrannosaurs were covered in fluffy yellow down like a baby duck” theory.
As far as I know there’s no evidence for feathers for any type of dinosaur other than the meat eaters.
Therizinosaurus, et al., were most likely herbivores (though they are classified as theropods) and at least one species of Psittacosaurus had quill-like structures on the tail, though calling those “feathers” might be a stretch. I’m pretty sure there may have been others, but I can’t think of them right now.
Fascinating! I’ll file that with my other favorite dinosaur theory: http://www.youtube.com/watch?v=fTOH8QK-6HA
It’s been a few years since I saw any details about this, but the study of feathers shows that they are not modified scales, and the analysis of DNA was indicating that the unique type of skin cell had developed much earlier than known birds.
The ‘feathered dinosaurs’ I’ve seen from China were clearly on their way to the classification of birds.
I meant meat-eaters in the sense of “Theropods”.
Teeps!
I’d just like to point out that the creatures in Jurassic Park aren’t really dinosaurs. They’re genetically engineered monsters cobbled together from dino DNA and DNA from frogs (among other animals in the book) for a theme park exihbit. Crichton gave himself a built in defence against paleontology marching on with that. Even discounting the genetic modifications none of the “dinosaurs” were socialized properly; which would explain alot of the raptors behavior.
Didn’t the Ripley’s show once featured a house in America tiled with quarry rock showing dinosaur footprints? It also showed a rock showing a cast of a dinosaur’s skin. Holes on the cast were interpreted to be skin pores.
There’s good evidence for true feathers in only one group of dinosaurs: the theropods, which mainly includes carnivores but also some groups that were probably herbivorous like the oviraptosaurs, ornithomimids, and therizonosaurs. Feathers and filamentous feather-like structures are very widespread among this group.
There are two main groups of dinosaurs, the Saurischians, including the theropods and the giant sauropods (“brontosaurs”), and the Ornithischians, including the other major plant-eating groups, including stegosaurs, ankylosaurs, ornithopods (“duckbills”), and ceratopsians (horned dinosaurs). There is no evidence for feathers in the sauropods, nor among most ornithischians. However, filamentous structures have recently been found on the tail of a ceratopsian.
Pterosaurs, which branched off the lineage that led to the two dinosaur groups, also had filamentous body coverings. This plus the finding of such structures in a ceratopsian has lead to speculation that they could be an ancestral condition among all dinosaurs. However, evidence so far is lacking that they were widespread in non-theropods, and in any case these aren’t really true feathers.
Even among theropods, structures which can be interpreted as feathers or feather precursors are only found as far back as Coelurosauria (assuming the structures associated with Dilong are what they seem to be); the coelurosaurian clades Compsognathidae and Maniraptora are where we first start to see unambiguous evidence of feathers.
So, that means even among theropods, there were probably unfeathered groups (e.g., Carnotaurus or Allosaurus). Filamentous integuments have been identified in a couple ornithischians - heterodontosaurs and psitticosaurs, in particular - but it is currently unknown if these are, indeed, any sort of feather precursor, or simple convergences.