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Dreadnoughtus schrani, or as I call it, Lacovara's titanosaur, is the newest giant on the block. Just described, after years of painstaking reconstruction and cementing thousands of fragments together. Not the biggest dinosaur, but still very impressive for its size and completeness.

Find out more on my blog here: paleoking.blogspot.com/2014/09…

http://4.bp.blogspot.com/-ebkMheGcLlQ/VBTSWLhj09I/AAAAAAAABWQ/hSxn1k_szVw/s1600/model.jpg

And here's the announcement from Drexel U: drexel.edu/now/archive/2014/Se…

And the paper itself: www.nature.com/srep/2014/14090…

No matter whether you agree or disagree with the paper's conclusions, this is one cool beast. And one impressive name.
Post your thoughts below. What do you like about this find? Heck, what's not to like!
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:iconvasix:
vasix Featured By Owner Oct 25, 2014  Hobbyist Digital Artist
Will you be putting up the skeletal on DA soon? And anyhow, how much bigger do you think the supposedly juvenile Dreadnoughtus could've grown?
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 26, 2014  Professional Traditional Artist
It will be awhile. But I can tell you it's not a "juvenile". Subadult might make more sense. There are no sutures in the vertebrae so this animal was probably well over half grown.

As an adult I suspect it would have pushed 100 feet. It's tough to compare that to Futalognkosaurus or most other less complete titanosaurs.... Keep in mind we don't even have a clue how big Futalognkosaurus got because the holotype doesn't include shoulder material (though two clearly immature smaller specimens do).
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:iconvasix:
vasix Featured By Owner Oct 26, 2014  Hobbyist Digital Artist
D. schrani's not designated as into any particular titanosaurian group yet then, is it? Plus, that whole 65-ton weight in the media seems a little bit far-fetched given that it looks so svelte in your corrected skeleton.
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:iconpaleo-king:
Paleo-King Featured By Owner Oct 27, 2014  Professional Traditional Artist
Good point.... I may have to revise the mass estimates for all my titanosaurs.

But I didn't make that skeletal, I just corrected the posture. It's still very crude and inaccurate to the fossils.

Dreadnoughtus may be either a lognkosaur or an argyrosaur. I am leaning argyrosaur but it's a bit hard to be 100% sure at this point.
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:iconvasix:
vasix Featured By Owner Oct 28, 2014  Hobbyist Digital Artist
Hmm....I still can't see how the original skeletal and all those renditions that appeared all over the media could have a neck sticking straight out so at such a painful angle when it should've been so much more different.
I myself secretly wish it would turn out to be an argyrosaur in any case, them being so heavy and stocky-legged
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:iconspongebobfossilpants:
I remember seeing an infographic stating that Dreadnoughtus weighed a third more than Futalognkosaurus; what say you?
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 16, 2014  Professional Traditional Artist
Well until I do a skeletal it's hard to tell. Based on the size of the hips and other remains I think the animals may have actually been quite similar in mass (around 65 tons).

The issue isn't that Dreadnoughtus was all that much bigger than Futalognkosaurus (it isn't, apparently). It's that the paper severely underestimates the mass of Futalognkosaurus and other big sauropods (40 tons for Futa seems a bit anorexic IMO, considering how wide the animal was, and how badly the ROM reconstructed its torso and limbs). However it looks like Dreadnoughtus MAY have a slightly longer neck.
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:iconblazze92:
bLAZZE92 Featured By Owner Edited Sep 17, 2014
I think that you really need to perform a GDI of your reconstructions before declaring estimates as severely underestimated or anorexic, Wedel's GDI of Dreadnoughtus following the "fixed" torso length is closer to 30 tonnes even when he is assuming a torso as wide as deep, so roughly 3.5m based on the skeletal, much more than the ~2.8m wide of the 3D reconstruction, how much wider can you make it? is it really going to double the weight of the animal?

You accept that Dreadnuoghtus was similar in size to Futalongkosaurus so if the above is correct there there's no way the later was 70 tons and the same goes for Paralititan and other sauropods.

I'm going to do a GDI of your Futalongkosaurus, I'll come back later with the results.

Edit: My attention span has run out, minus the tail your Futalongkosaurus skeletal has a volume of ~53m^3 which means a mass of 37 tonnes assuming a density of 0.7kg/m^3, I expect the tail to add another 2 tonnes at most, I'll edit this comment again when I'm done with the tail

Edit 2: The tail was bigger than I expected, anyway total volume of your Futalongkosaurus skeletal is ~57m^3, which means a mass of ~40 tonnes assuming a density of 0.7kg/m^3.  
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 17, 2014  Professional Traditional Artist
Well the basic volume formula doesn't lie. (LxWxH = V, V x D = M) If you increase width and height (or width and depth for a limb cross-section) you will essentially start growing the mass exponentially. A limb that's made 25% wider and 25% deeper while maintaining the same length will be 56.25% greater in volume. 1.25 x 1.25 x 1= 1.5625. The GDI is only as good as (a) the soft tissue restoration, and (b) the preciseness of the equation with regard to it. So if you do a Greg Paul style restoration and your equation heuristic is spot-on (or as close as possible) you may get 40-50 tons for Futalognkosaurus (as Greg himself did). If you use a Nima Sassani restoration your results will be quite different.

I'm not sure how you get your GDI figures. Do you take into account the depth of the portion of the torso that extends beneath the ribs? How deep is the belly in your version? Do you add enough soft tissue to round out the limbs (which in Dreadnoughtus are very thick) or do you just slap on barely enough to hold it together?

Yes you can double the weight of the animal if you reconstruct it the way I reconstructed Futalognkosaurus. A rib cage that's wider than deep (how feasible this is for Dreadnoughtus, I will have to see), and thicken the arms and legs as is appropriate for such robust bones. I believe it was Mike Taylor who said that the limbs are heftier than average relative to the torso so the GDI has to take that into account too.

In Paul 1988 there is a pretty convincing discussion of how GDI and limb-bone allometry models can vary by a factor of two depending on how you reconstruct the soft tissue. If we followed only GDI or allometry equations the way Dale Russell did, you'd end up with Brachiosaurus and Giraffatitan weighing around 12-15 tons because he used diplodocids as his reference point for the equations - and those estimates are indeed anorexic. This is why using formulas alone can only yield ball-park estimates - some animals have different morphology and a lot more flesh per inch of limb bone circumference than others. Which is exactly the same conclusion Mike Taylor pointed out on SV-POW. GDI estimates can produce numbers that are radically off depending on the reference point, and can veer off very far from what a displacement model would tell you.

BTW the standard soft-tissue density of most large animals today is 0.9, not 0.7. The neck however may be 0.6 (or more or less depending on the species). And we can't forget that much of the animal is blood which is slightly greater than water density.

From what I recall, GDI uses cylindrical sections which are not all that appropriate for all the odd dinosaur shapes out there (unless you do thousands of slices which still makes a lot of assumptions about the density of the contents). I tend to put more stock in mass estimates when the volume is measures by displacement of a physical model rather than by GDI. 40 tons for Futalongkosaurus flies in the face of everything that the skeleton says versus Brachiosaurus, which may mass around 35-40 tons for the 80-something foot holotype and ~55 tons for the big Potter Creek specimen. Futa has a much wider torso and spinal column, a wider and deeper neck without all those camerae, more massive hips, a wider and deeper chest cavity, much thicker limbs and more massive hips, probably a denser tail too. Yes Futa has a short torso as does Dreadnoughtus, but there's so much more to account for that GDI's leave out. I don't hate GDI estimates, it's just that you have to take them with a big pinch of salt. I'd do the same even if I was the one doing the GDI.
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:iconblazze92:
bLAZZE92 Featured By Owner Edited Sep 17, 2014
I used your skeletal at the maximum resolution you have it available without buying a print (1600px by 1131px), I used 171 10px long slabs (210 if I count each limb separately), 1px long slabs would be ideal but that would have taken too much time though I think there's software that can do that from what I heard, still 10px is not bad at the resolution of your skeletal. The more slabs (or slices) the more it approximates the actual 3d form (think number of polygons in video game characters).

I don't think you quite understand how it works or what it is and Russell didn't use it, he used allometric equations and limb bone circumferences. I also checked Paul 1988, he doesn't mention GDI at all, I don't think the method had been used for this purposes before the late 90s. With GDI you are basically making a digital volumetric model so given enough slices it shouldn't be worse than physical volumetric methods and of course it depends on the accuracy of the model used, if you use a super fat retro sauropod reconstruction it will give you ridiculous estimates just like the 78 tonnes for Brachiosaurus which was obtained with water displacement of scale models, read Henderson (1999) or the SVPOW post about it.

All the assumptions on soft tissue are on your behalf, I only tried to use as many slices as possible to make sure the "digital" model is a good representation of your reconstruction and a volume of 57 m^3 is what it ended up with, the density I used I used it because that's what Matt Wedel used in his GDI of Dreadnoughtus and because it is a likely density for sauropods based on the most recent research, your numbers come from Paul (1988), back then we barely recognized how pneumatic sauropods were.

How were you doing your estimates? did you made physical models and used volumetric methods with water displacement or were you just eyeballing them?
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 17, 2014  Professional Traditional Artist
I am familiar with the crazy 78 ton estimate. Yes that model was way off, and Paul (1988) debunked it way before Henderson.

I basically worked from volumetric methods using expansion factors of the volume equation L x W x H for fatter dinosaurs like Futalognkosaurus. The "true north" was 33 tons for HMN SII Giraffatitan similar to the GSP 32 ton estimate, but longer neck (not SI anterior parts but SII's) and considerably more soft tissue on the limbs, but balancing it out by lowering the density of the neck.

MY estimates are rough ones it's true. However increasing any one of the 3 factors in the volume equation has a substantial effect on volume and mass. The more factors increase, the more exponential the outcome.
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:iconblazze92:
bLAZZE92 Featured By Owner Sep 17, 2014
But it is too simplistic and ignores the true 3D shape of their bodies, just look at the differences, you got 70 tonnes and I got 40 (45 allowing for a higher density of 0.8). You should definitely learn to perform a GDI, it is very simple, there's only two real formulas used, one to estimate the volume in px and another to transform that to liters and that's it, you could just copy-paste them where you need them, that's what I do, I have no written them again since the first time I made a GDI, I only change the scaling factor because that depends on the scale the skeletal is at.

Here's SVPOW's post on how to do it.

btw, Henderson didn't debunk the 78 tonne estimate, I mentioned Henderson 1999 because it explains how GDI works.
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 24, 2014  Professional Traditional Artist
I got 50 tons. So it was lower than my estimate but not that low. Considering a neck of similar length (but wider and much deeper) and a much larger tail, thicker limbs and a torso that's on average wider and deeper (but not longer) this makes sense. Volume turned out at about 50% greater than Giraffatitan HMN SII, which is about 33 tons. Not twice as much volume, just 1.5 times. Of course my old estimate relied on excessively large and wrong scaling estimates for Futa's torso, limb length, and overall dimension, so this makes sense. Still I'd be more confident using a displacement estimate. Call me old-school. I've also seen different results using different density figures, so there's definitely a margin of error there.
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(1 Reply)
:iconvigorousnebuladragon:
The official reconstructions published along with the paper are just way too off for me. And somehow in the paper Giraffatitan and Futalognkosaurus became extremely lightweights.
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 15, 2014  Professional Traditional Artist
True. The horizontal neck, oddly arched back, and the neural spine shapes and angles are just wrong. Plus even with the 3D model the crushed and flattened ribs are mounted onto the vertebrae as-is, and at the wrong angle.... which creates the false impression that this was a thin, slab-sided animal, when this doesn't agree with the wide hips and flies in the face of everything we know about intermediate and derived titanosaurs.

These animals were, I think, not lighter but heavier than the official figures. And they can be heavier without being all that much thicker. Greg Paul estimated Girafftitan HMN SII at 32 tons, including somewhat under- accounting for the pneumatic neck. Increasing the pneumatization of the neck to the level that it's understood to be pneumatic today results in a GSP Giraffatitan that's around 28 tons. Well, add a reasonable amount of muscle to the limbs to make them not so emaciated, and extend the neck as per HMN SII instead of frankensteining the shorter SI onto its top end like GSP did, and you get 33 tons without too much effort.

Just the huge span of the hips of Futalognkosaurus makes it highly believable it was ~65 tons. They are over 8 feet wide! The legs alone would have to be massive. And the torso was much wider than the ROM reconstructed it (in their version the ribs didn't match the wide hips, and half of the material wasn't even from Futalognkosaurus, they actually replaced some of it with up-scaled casts of juvenile Alamosaurus material from different-sized specimens, especially the skinny lower limbs!) . You have to make sure the ribs are properly angled and you account for erosion.

There are many major errors in "official" reconstructions, honestly I don't know why they do this, probably haste due to lack of budget for hiring skilled artists of the likes of me? :XD:  These errors are what I attempt to rectify in my skeletals. For what it's worth, the Dreadnoughtus paper does include a lot of things you don't find in your average description paper, for one thing just about all the material is figured and you don't have to guess at it. It's just when it comes to interpreting the material that the paper goes off the tracks a bit...
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:iconyty2000:
yty2000 Featured By Owner Sep 16, 2014
As Matt Wedel pointed out on SVPOW, the official reconstruction depicts the torso to be 15-20% too long.
The specimen looks to be about as large as the Brachiosaurus holotype, judging with my naked eyes that is. It seems to have a longer neck, shorter legs, but bulkier torso and hips than Brachiosaurus, so it could very well weigh somewhere between 30-40 metric tons.
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 17, 2014  Professional Traditional Artist
The torso in the official skeletal is indeed too long (among many other errors).

However it's also reconstructed far too narrow, using the crushed ribs AS-IS. So it's proportioned more like Futalongkosaurus than Brachiosaurus. Based on my reconstruction of the Brachiosaurus holotype (longer neck than Mike Taylor's, based on cross-scaling additional referred specimens), it was around 37 tons. Giraffatitan HMN SII is about 33 tons. Far as I'm concerned that's just unfeasible for an animal like Dreadnoughtus, it may have had similar length torso to Brachiosaurus but that's where the similarities end. The vertebrae are so much wider and more massive. I would estimate the torso was at least 50% wider uncrushed, may have been around 20% deeper, and the limbs are over 50% more robust anyway just by looking at them. Add in a dose of conservative volumetrics (LxWxH = V, V x D = M) and it's possible for this animal to have almost twice the mass of the Brachiosaurus holotype.

The main obstacle to envisioning this probability is that both the 2D skeletal and the 3D model have some glaring errors that provide an incorrect idea of this animal's scale and shape. With the 3D model there may not have been time to estimate the shape of uncrushed ribs though. The width of the hips indicates a much wider ribcage was originally in place.
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:iconyty2000:
yty2000 Featured By Owner Sep 17, 2014
What you said about torso length is not true. The functional length of Brachiosaurus' D6 through D12 is 226cm. If we assume D1 through D5 is on average slightly shorter than D6, say 35cm, the torso as a whole will be 401cm long. Matt Wedel estimates the Dreadnoughtus torso to be 285cm long, both not taking cartilage into account. So Brachiosaurus could have had a torso that is 40.7% longer.
How do you figure the ribcage to be both much wider and deeper? If the ribs are crushed, wouldn't the ribcage be rounder but shorter in real life? I mean, the ribs seem flattened, but I cannot imagine the length being greatly reduced during preservation.
Brachiosaurus has a pretty deep torso too, although not as wide as most Titanosaurs proportionally. I think the two animals will end up with torsos roughly equal in volume, Brachiosaurus being much longer, and Dreadnoughtus a lot "fatter". If your Giraffatitan is 33 tons (metric?), then Brachiosaurus is gotta be as much as 40 tons. I estimate Dreadnoughtus to be around that mark too, about 40 tons.
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:iconpaleo-king:
Paleo-King Featured By Owner Sep 17, 2014  Professional Traditional Artist
The ribs shown in the paper are both crushed and fragmented at the end, and there's no telling if the restores position is even correct. So the torso may be deeper as well as wider, in fact I find this likely judging by the proportions of related animals.

However there's also the belly which is not filled in all the way down by ribs. It may extend well below the ribs, especially in titanosaurs where the rib cage doesn't recurve in much below the lateral max. width point. This is easy enough to see in Rapetosaurus, where the ribs didn't undergo much crushing. The FMNH mount shows how little of the belly (ventral torso) was actually encased by the ribs.

The lenght of the Dreadnoughtus torso depends on how long the missing vertebrae were. It's probably shorter than the paper reconstructed it but the whole column isn't known so there's possibility of some alternate hypotheses there. Also if you read my blog post you will see where the torso depth is distorted down by not making the space of the hands long enough. Fixing this raises the shoulders and front torso and creates more room for a deeper belly, as well as making the neck more vertical. The position of the sternals in the 3D model also looks a bit too tight, pressed up deep and forward into the chest cavity. A deeper chest increases mass. The main problem in dinosaur reconstructions these days is that most authors tend to try to isolate aspects - it's too easy to miss the forest for the trees. Everything is connected: the proportions, the height, the depth of the torso, the mass, the neck position, the posture overall. Mess up one thing and you mess up many others to a certain degree. And this is often why GDI results in general are so problematic and contradictory - being detached from the visuals and the anatomy can allow one to overlook glaring errors and assumptions in reconstruction.
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:iconvigorousnebuladragon:
Even the official paleoarts are dissatisfying to me. :P I really want to draw one now but apparently it's better to wait for your skeletal diagram first.
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:iconpeteridish:
PeteriDish Featured By Owner Sep 14, 2014  Hobbyist General Artist
to be completely honnest, I am not very impressed by the name... Waiting for "Bigasshitsaurus" next year... :/
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:iconmrgorsh:
MrGorsh Featured By Owner Sep 14, 2014  Hobbyist Digital Artist
To me it's roughly on the same level as Lythronax. Not exactly what I'd call my favourite name, but I think it's better than another "saurus".
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:iconthedilophoraptor:
TheDilophoraptor Featured By Owner Sep 14, 2014  Hobbyist General Artist
I think Lythronax and Dreadnoughtus are fun to say, thats probably why they are my favorite names so far.
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:iconpeteridish:
PeteriDish Featured By Owner Sep 14, 2014  Hobbyist General Artist
fair enough
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