Oh dear. For a self-proclaimed 'dinosaur expert' you sure have a LOT of your facts wrong. Well, sit right up and prepare to be schoolfed, because it's time for
StellarWind Elsydeon's Biology Corner!
Thank you, you're too kind. Ahem. Anyway.
The clade
Dinosauria can be divided to two major orders - the
Saurischia ("Lizard Hipped") and the
Ornithischia ("Bird Hipped") - both terrible misnomers kept for historical reasons - as birds actually arose from Saurischian dinosaurs whereas Ornithischians left no living descendants.
Ornithischian dinosaurs were beaked primary-herbivores and the order includes many 'famous' groups of dinosaurs - Stegosaurids, Ankylosaurids, Marginocephalians (that is to say, Ceratopsians and Pachycephalosaurians) and Ornithopods (such as the 'duck-billed' Hadrosaurs) were all Ornithischians. Saurischian dinosaurs can be further divided to
Sauropodomorphs and
Theropods, alongside a few basal species that aren't
quite either. Since we're on the subject of dinosaur feathers, let's talk Theropods - as the Theropods (and specifically maniraptoran theropods) were indeed the first group where evidence was found for plumage - though over the years a large body of evidence popped up and suggested that most theropods (including some of the odder beasts such as
Deinocheirus) were at least partially (if not fully) feathered. And since we've gone and mentioned those, let's get some confusion out of the way.
The 'raptor family' (or at least, what most people think of as the 'raptor family' unofficially) has a proper name -
Dromaeosauridae - and it does
not, in fact, include Troodontids. The placement of those on the tree of life is still under debate, some believing they form a natural group with Dromaeosaurids while others place them closer to Avialans (the group containing modern birds). Now that we've clarified what is and isn't a "raptor", let's get one thing out of the way -
Eoraptor was NOT actually a "raptor". In fact - in all likelyhood it wasn't even a Theropod. The early age of Eoraptor and the fact it has traits that may be ancestral to both Theropods and Sauropodomorphs suggests that it quite a basal
Saurischian (and even then, it may not have been the 'ancestor' of both Saurischian lineages - several other lineages exist whose placement is uncertain and could predate Eoraptor). It, however, does not account in any way for the Ornithischian side of the Dinosaur branch - so whoops, there goe
s the idea of it being the common ancestor of all dinosaurs out the damn window.
In any case. Feathers - or at least proper
feathers (incidentally, 'plumage' means the same thing as 'feathers' - unless you're trying to make a distinction between assorted protofeathers and central-shafted feathers akin to those on modern birds) - were thought to be entirely a theropod thing until fairly recently, a quirk of the particular lineage that led to birds and its close relatives - whereas the Ornithischian side remained quite unfeathered (although filamentous quill-like structures that may or may not be homologous to theropod feathers were found in
Psittacosaurus and
Tianyulong). A study of many dinosaur skin impressions
as recent as December 2013 suggested that the ancestral condition for dinosaurs was most likely scales rather than feathers - albeit it's possible that these scales were already well on their way to evolve into quill/feather like structures.
Then, everything changed when
Kulindadromeus zabaikalicus attacked. That is to say, when a small Ornithischian herbivore that had both scales and some form of feathers was discovered in Siberia and dated back to the mid/late-Jurassic. This has made people speculate that
Feathers? In MY Dinosaurs? It might have happened a lot earlier than you think. Naturally, this inspired a lot of clickbait - and for people who get most of their scientific information wholesale from sites such as 'I Fucking Love Science', that usually suffices. Those of us who actually do love science, though*, tend to actually read more than just the header of an article and think critically about the described study's methods and conclusions before regurgitating half-chewed facts at message boards.
* Regardless of our relative degrees of interest in the part suggesting sexual intercourse with aforementioned science.
As for dinosaur thermoregulation - there's a
hell of a lot of debate on the subject, but it's generally thought that dinosaurs were most likely what one would call
mesotherms - neither poikilotherms ("cold blooded") nor homeotherms ("warm-blooded") but rather something in between, adjusting their body temperature to a metabolically convenient one through a combination of metabolism-produced heat and environmental cues. And to be fair, unless you're still stuck in the sixties, it's hardly surprising.
Also! You've mentioned arctic
Troodonts. While it's true that
Troodon was found as far north as Alaska, you must take into consideration the fact that what you think of as arctic climate today may not have held at the time these animals lived. As the matter of fact there is evidence (mainly the presence of warm-adapted plant fossils) that the climate in these areas was far warmer in the particular chunk of the Cretaceous when Troodonts lived than it is today, so there's another argument that doesn't quite hold water. Nevertheless, it is rather likely that these animals were feathered and so the question of whether or not they could have survived without feathers up north is fairly moot.
Anyway! I've been going on on this post for a few hours and quite frankly it's about time I posted this and stopped rambling like the deranged bio-geek that I am. I would however suggest checking your facts and doing your own research - and above all
not assuming you know something we don't - before calling yourself an 'expert' and proving you are anything but.
That's all. Armblades out.
It's just so damn adorable and I don't even know why! I ended up raising one in Pokemon Y and even if I'd never use it competitively, I deeply love this silly bearded dinosaur. Definitely within my top favourites of the Gen VI Pokemon. ^^
I WANT TO KNOW IF T-REX WAS COLORED PINK WAH!!!!!!!!! 
'just kiddin'
