Ordinarily, I would be WAY too terrified to post this in a public forum, but over the past few weeks, I’ve grown tireder and tireder of the paleo-fandom’s shit, so today I’m going to take a stand.
Not all dinosaurs had feathers. Not even most dinosaurs had feathers. All birds are dinosaurs, but not all dinosaurs are birds. Dinosauria is a massive group, and a statement like “dinosaurs had feathers”, while technically true, is also highly misleading. It makes more sense of you’re part of that massive group of the fandom(and it IS a fandom) that only cares about theropods.
Phylogenetic bracketing is a useful tool because it tells us “this animal is related to this one, so what we know about one helps us fill in the gaps in our knowledge.”
Skin impressions also fill in the gaps. Therefor, skin impressions > phylogenetic bracketing.
And skin impressions tell us that:
Most sauropods had scaly skin. There is evidence that they had spines or bristles along their backs, but these wouldn’t have been proper feathers, and would’ve probably looked more like those of an iguana.
Most ceratopsians had scaly skin. It was suspected they may have had dorsal bristles due to impressions discovered on psitticosaurus(a basal ceratopsian)’s tail, but those turned out not to be feathers. Knobs discovered on triceratops’ back, first thought to be broken off bristles were more likely osteoderms, like those of a crocodile.
Most hadrosaurs had scaly skin.
Most stegosaurids had scaly skin - and osteoderms on their necks.
Ankylosaurs had scaly skin.
Most abeilosaurids(or at least carnotaurus and its closest relatives) had scaly skin.
At least some carnosaurs had scaly skin.
Maniraptors were definitely feathered, which includes the iconic dromaeosaurs, ornithomimids, therizinosaurs and even modern birds.
At the time of this writing, the jury is still out on whether or not T.rex had feathers.
No, it really is. The most substantial evidence in favor of a feathered T.rex is skin impressions from a tyrannosauroid, but not a tyrannosaurid. That’s something, sure but we also have skin impressions from albertosaurus(A more closely related animal) which show scales.
Now, some evidence suggests that, evolutionarily speaking, dinosaurs had an easy time changing their integument. Feathers have been found deep in dinosaur lineage, only for their descendants to still show scales.
We need to remind ourselves that form follows function. Dinosaurs were not growing feathers because birds are higher on the evolutionary ladder than reptiles. They were growing feathers because natural selection favored them, for one reason or another. And when natural selection took them on a path that favored thick, scaly hide(for instance, being a large herbivore that needed to defend itself from predators) that’s what they developed.
Now, all of those groups I listed above were pretty massive themselves. Is it possible that some members of those groups had sparse bristles, feathery crests, or even full coats in isolated pockets of the evolutionary tree? Sure.
I reiterate: Dinosauria was an ENORMOUS group. Consider the differences in feather structure between different birds, and then remind yourself that birds are a tiny group within a tiny group within a tiny group, within a tiny group, within all of dinosauria.
Now, to everyone who took one look at this list and started sending me angry messages, do us both a favor and don’t. Everything I’ve said here is supported by our knowledge on the subject at the time of this writing. If that angers you, then the problem is with your personality.
I’m looking at you, person who’s digging up a fossilized skin impression of a maniraptor.
I’m looking at you, person who’s going to accuse me of thinking dinosaurs were tail-dragging, cold-blooded lizards.
I’m looking at you, person who thinks I’m just mad because they think I hate birds(I don’t. I love birds.)
I’m looking at you, person who read an article about filaments found in early Triassic dinosaurs once, and horribly misinterpreted the meaning.