Updated Stegosaurus by Scott Hartman

[suspsy]

http://scotthartman.deviantart.com/art/Roofed-reptile-overhaul-75933986

From the link:

2016 update: As strange as it must seem given how often Stegosaurus has been portrayed and how many specimens are known (for well over a century!), but we actually knew surprisingly little about the basic proportions of Stegosaurus until very recently. That's because previous specimens were either not prepared out all the way (to preserve taphonomic data) or were mounted as composite specimens.

That all changed last year when Maidment, Brassey, & Barrett published the Sophie specimen: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0138352

Among other things it turns out that Stegosaurus has more cervicals and fewer dorsals had been previously been thought. This results in a less tall-bodied and longer-necked animal. In retrospect perhaps this isn't shocking - Kentrosaurus appears to also have had a longer neck than some early reconstructions suggested, and of course Miragaia took this one extra step in its neck-elongation.

Another odd feature is that the tail has a distinct down-curve in the posterior portion. I've gone over the distal caudals several times and the downcurve does not seem like a preservational artifact, so I'm including it in the reconstruction. One interesting side-effect of this is that the thagomizer is now oriented at a more useful angle for swinging at an attacker (I do not consider the laterally-facing spike suggestion to be likely), and notably other stegosaurs also seem to have their distal tail spikes end up facing closer to horizontal as well, either through tail articulation or by changing the angle of the spikes.

So now Stegosaurus does not stand out quite as drastically from its close relatives. It still looks pretty cool though, if you ask me.

Cool stuff. Doug Watson, I hope you weren't already working on a Wild Safari Stegosaurus for 2018!

[SpartanSquat]

Thanks for the new! Its my idea or Ark Stegosaurus predicted the longer neck? Also what happened the bones found in the throat?

[Pachyrhinosaurus]

It looks like we're going back to the thagomizer spikes pointing up. It certainly isn't the high-tailed WWD stego I grew up with but it's fascinating to see how our perceptions change with new evidence.

[The Atroxious]

Somehow, this doesn't surprise me for the most part. It looks good, too. It makes sense that Stegosaurus would have a longer neck, considering the proportions of other stegosaurs. I was caught off guard by the downward-pointing tail and the angle of the spikes. It makes sense, considering that the spikes would have made the less reinforced tail tip heavier, causing it to bow, while also allowing the animal to deliver slashing attacks. I'm just surprised because I also thought the outward-pointing tail spikes made a lot of sense, and I'm used to seeing dinosaurs with very straight, muscular tails, so the bent tip seems very unusual. For some reason I thought I had read something about how Stego had evidence of muscle attachments on its tail that indicated outward-pointing spikes. Am I remembering this wrong?

The lack of gular ossicles is interesting though. I'm not sure if it was left out because of any new evidence, or just for the clarity of the diagram. I strongly suspect the latter, but more information would be nice.

I'm rather curious if this new specimen sheds light on the way the dorsal plates were arranged in life. I know that's always been something of a mystery given that the plates are not articulated in any way, and scientists have just arranged them the best they could with the information they had, but considering this specimen was apparently well preserved enough to show evidence of a natural tail posture, I wonder if the plates were also preserved in a way that showcases their positions in life.

[Kayakasaurus]

I really like it! It seems to have an overall longer look. 

[Newt]

The lack of gular ossicles is interesting though. I'm not sure if it was left out because of any new evidence, or just for the clarity of the diagram. I strongly suspect the latter, but more information would be nice.

Scott says in the comments (which predate the updated reconstruction but probably still apply) that he left out the gular and other dermal ossicles for clarity.

[Halichoeres]

Also the new specimen doesn't include the gular armor in the first place, which the authors speculate is due to either taphonomy, or potential ontogenetic or sex differences.

[Dinoguy2]

I'm curious how he justifies the long neck when several papers have argued it's probably wrong in that mount. Sophie as a whole is a very weird Stegosaurus and differs in some major ways from the type specimen of S. stenops. Either there are a few different species or there's some serious ontogeny happening here. Just compare the relative plate size and shape of this with the holotype.

[stargatedalek]

Length of the neck aside I'm not big on the choice of posture (but I almost never am with Hartman's skeletals). Even with stocky necks it's very rare for them to point directly forwards like that in a straight line, even when it looks like it would in the flesh (and modern archosaurs have perhaps the most deceptive of necks, albeit in birds largely due to feathers).

Additionally I'm not sold on the tail. Vertebrae don't always connect in the manner most obvious, and this case feels like it could be (at least in part) a subconscious choice brought on by the aim to justify the "classic" vertical orientation of the spines (as Hartman has already made note his preference for them).

[Doug Watson]

Cool stuff. Doug Watson, I hope you weren't already working on a Wild Safari Stegosaurus for 2018!

"Only the Shadow knows"..............and a bunch of people at Safari ltd.

[CarnegieCollector]

Interesting!

[laticauda]

Cool stuff. Doug Watson, I hope you weren't already working on a Wild Safari Stegosaurus for 2018!

"Only the Shadow knows"..............and a bunch of people at Safari ltd.

Oh come on Lamont Cranston!!!!     You can't put that out there to a Stegosaurus fan and not say anything.  Now its going to be stuck in my head, wondering, pondering, and knowing that I will not know for another year.   

[Mamasaurus]

its nice to have an official description of Sophie. I'm not a huge fan of how Mr. Hartman depicted the position of her neck (I say "her" for simplicity, since the specimen is often called Sophie). But honestly neck position is something easily remedied in an illustration. I'm sure he chose that for clarity, so that the neck plates don't overlap.

As far as the drooping tail...why not? The end of the tail is quite heavy and more flexible than the rest, like a flail or morning star. Of course I'm sure stegosaurus was quite capable of holding its tail out straight, since it seems to have been well muscled throughout its length. But what about when it was relaxed, no threat in site?  Gravity works on us all, and a stegosaurus wouldn't be constantly holding up the heaviest end of its tail.

One last thing.

The paper has a very detailed illustration of the specimen in situ. If that is truly how the specimen was found (and I don't see why it wouldn't be) then I'm inclined to think the spikes pointed vertically as illustrated in this skeletal. I've always been a fan of the horizontal orientation, and it makes the most sense as a weapon of we assume the usual side-to-side tail motion.  But the in situ diagram shows the tail spikes lying on top of one another.

Not what I expected to see. Horizontally oriented spikes would presumably end up on either side of the tail, or at least at scattered angles. But these spikes are laying on top and parallel to each other. Which suggests they were vertically aligned.

Which really hints at a novel way of tail movement and articulation.  Very cool!

What are your thoughts?

[Stuckasaurus (Dino Dad Reviews)]

The lack of gular ossicles is interesting though. I'm not sure if it was left out because of any new evidence, or just for the clarity of the diagram. I strongly suspect the latter, but more information would be nice.

Scott says in the comments (which predate the updated reconstruction but probably still apply) that he left out the gular and other dermal ossicles for clarity.

Shouldn't the soft tissue outline of the neck at least be thicker in that case?

[stargatedalek]

The lack of gular ossicles is interesting though. I'm not sure if it was left out because of any new evidence, or just for the clarity of the diagram. I strongly suspect the latter, but more information would be nice.

Scott says in the comments (which predate the updated reconstruction but probably still apply) that he left out the gular and other dermal ossicles for clarity.

Shouldn't the soft tissue outline of the neck at least be thicker in that case?

His soft tissue reconstructions are always minimal, some people will say it's because they only show muscle mass but I'd argue it's just the conservative nature of his reconstructions.