"Tsk" is for Elephants, "Tut" is for Kings @thuat-squared-blog - Tumblr Blog

Answering questions from around the paleo-Internets, as I find continually that I’m not happy with the answers that are given. @joyfullygeneralhideout asked: I still believe that Dracorex, Stygimoloch, Raptorrex, and Nanotyrannus are each their own species. What do you think?

On “Nanotyrannus”: (you can skim over this, as I see the good @raptorcivilization has created a good review of the same information). The best summary of what’s wrong with designating “Nanotyrannus” as its own genus/species classification is given by Dr. Thomas Carr, here. In short, there is nothing anatomically distinct about the “Nanotyrannus” holotype (specimen used for the name) that is totally unique from other tyrannosauroids, or even young Tyrannosaurus rex. This has become more evident with the analysis of “Jane,” the juvenile Tyrannosaurus at the Burpee Museum that died at about the growth stage that the “Nannotyrannus” holotype is in. The LA County Museum has a specimen within the same age range as Jane. As we discover more young Tyrannosaurus, arguments for “Nanotyrannus” like the higher number of teeth become debunked. Dr. Carr is writing a monograph detailing the specifics of the Jane specimen as we speak, in which I am sure he’ll refute the arguments for “Nanotyrannus” in full.

To my knowledge, no other tyrannosaurine specimens beyond the holotype have successfully been assigned to “Nanotyrannus,” as a result of the fact that the holotype has no distinguishing characteristics from Tyrannosaurus or other tyrannosaurines. The shape of the holotype is more likely the result of geological deformation than of genetics, or the warping due to prolonged pressure under rock for millions of years.

On “Dracorex” and “Stygimoloch”: I think this video, in which Jack Horner goes over the science behind lumping based on growth stages, explains it very well. Juveniles start their lives with porous bones that become more dense as they age; this is something we see across vertebrate life histories. Other signs of skeletal maturity include fusion of the cranial bones, vertebral bones, and pelvic bones (which is why babies’ heads are so soft, and why they’re flexible). I have relevant links here. In Horner’s talk and in the relevant literature, there is a consistent running theme that “Dracorex” and “Stygimoloch” cannot be skeletally mature individuals because their bones are too spongey. Set them side-by-side with Pachycephalosaurus and the picture becomes much clearer--”Dracorex” has the youngest bone, “Stygimoloch” is older, and Pachycephalosaurus is skeletally mature. If we had more vertebral material for “Dracorex” and “Stygimoloch,” we would expect to see them unfused in correspondence with the growth series we see in their cranial textures. It’s difficult to argue against this: They live in the same localities and time periods, and even if they are separate species from Pachycephalosaurus, we don’t have adults for the first two. Given the evidence, we shouldn’t expect to find any.

On Raptorex: To my knowledge, the specimen was determined to be a juvenile and likely corresponds with the same time period as Tarbosaurus. Considering its similarities with other young tyrannosaurids, it’s a dubious taxon (nomen dubium) since we can’t confidently identify it as distinct from other taxa. It essentially suffers the same problems as “Nanotyrannus” and the juvenile Pachy taxa. Here’s a paper detailing this line of thought.

On the original blogger hounding on you for what you think: I strongly disagree with the approach that was taken with regard to this question. I’ll assume that you are either uninformed/misinformed, but I won’t go through the mental gymnastics to equate your line of thought with an inability to weigh evidence and to critically think. That’s unfair. A lot of people are just as uninformed or misinformed as you are on this topic; otherwise there wouldn’t be so much confusion about it. They’re right on the simplest explanation being the most scientific approach--but shooting you down like that is not acceptable, especially when it runs the risk of driving not only you but other un/misinformed people like you away from the science. Education is about talking to people who don’t know a topic and keeping them engaged. One can’t do that with toxicity and hostility toward newcomers.

viergacht

A sign outside the theater in the local mall. I bet you didn’t realize South Africa was plagued by pickpocketing dinosaurs.

a-dinosaur-a-day

@palaeofail-explained

shibesky

Get ready to get educated by a fourteen year old dinosaur nerd you dick heads. 1) Dinosaurs most likely all had some form of feathers, from quill like to fuzz. The Raptor is one of the groups of dinosaurs who most definitely possessed feathers due to almost all of the raptors having some sort of a trace of feathers on their body and they were probably all covered form head to toes except for the feet and nose (making it look more like a bird, that doesn’t mean they can’t be scary. They are still deadly and creepy as FUCK). 2) birds evolved from dinosaurs. You know what birds are? Idiots. They are not the smartest creatures you could come across, believe me I have had two and currently have one really obnoxious cockatiel. Most modern day birds are smarter than dinosaurs which says something. The smartest dinosaurs was as smart as a turkey and I can tell that it was not a raptor. Dinosaurs are idiots. 3) dinosaurs can’t pick pocket, they are to dumb and they’ll grab your hand instead of your wallet and then look into your eyes and fall in love causing the two of you too marry and live happily ever after. You just got educated dib shit.

a-dinosaur-a-day

Well, no, dinosaurs couldn’t pick pocket, but birds are actually exceptionally intelligent animals. They have higher neuronal density than mammals do and many of them - including things like pigeons - are smarter than most mammals. Many parrots are able to actually talk with their humans and have their intelligence estimated at about the level of a small child (remember, obedience to humans =/= intelligence, and most parrots are terrible pets because they aren’t domesticated, so they act out and do what we see as “stupid” because they actually really hate living inside of your house). Ravens and Crows are probably the second smartest animals on the planet (after humans) and are probably able to distinguish between different individual humans as well as their own kind.

This high neuronal density has not been studied in non-avian reptiles so it’s uncertain when exactly it evolved; but given many dinosaurs have had brain-to-body size ratios that baffled scientists (”stegosaurus must have had a second brain, amiright” and other such nonsense hypotheses were very common back in the day) it is entirely plausible that high neuronal density evolved at the base of the dinosaurian tree. Though this wouldn’t make raptors be as smart as the ones in Jurassic Park, they still would not have been dumb.

And not all raptors are known to have evidence of feathers but enough of them do, and the relatively low plasticity of feather integument as a trait in modern dinosaurs means that the odds of any dromaeosaurid dinosaur not having feathers are zero

The main problem a raptor dinosaur would have with pick pocketing is the fact that they cannot pronate their hands; only being able to hold their hands in a “clapping” motion limits the range of movement of the hands. Trying to grab someone’s wallet when you can’t move your wrist much poses many problems. Not to mention the wing feathers (since Dromaeosaurids would have had full on, pennaceous feather covered wings like modern birds) would definitely have attracted attention during the aforementioned thievery.

gilkenansmonsterhouse2006-deact

why did either of you feel the need to add your comments

a-dinosaur-a-day

Do you even know what my blog is about

i-was-once-a--tortoise

listen i love feathery raptors as much as the next guy but this is an obvious movie reference. that’s a JP raptor right there. this isn’t a legit attempt at proper palaeontology you don’t need to pick it apart you vultures.

drewbern

Holy fuck dinosaur tumblr is so embarassing

i-was-once-a--tortoise

i say this as someone who enjoys a lot of what dinosaur tumblr does: it really, really is.

on the one hand you’ve got a bunch of people who love dinosaurs and are usually good scientists, which i like.

on the other, you’ve got a group of people who have a really hard time telling the difference between a bunch of people having fun and an opportunity to ruin said fun by “debunking” inaccurate portrayals of dinosaurs that nobody was really thinking were accurate in the first place.