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Patagotitan mayorum skeletal reconstructions
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Published: October 1, 2017
© 2017 - 2019 SpinoInWonderland
Patagotitan mayorum ("The Mayo family's Patagonian titan"), the Chubut Monster, is a species of gigantic titanosaurian sauropod that lived on what is now Patagonia, Chubut Province of Argentina, South America during the Albian stage of the Middle Cretaceous. It was first excavated and exposed to the media in 2014, and described in 2017.

It was initially speculated to be ~37 metres long, with a femur stated to be in various sizes ranging from ~2.4 metres to ~3 metres. The measurements in the description then showed that the gigantic ~37-metre figure as implausible for any of the known specimens given regular titanosaur proportions.

It is commonly famed for being larger than Argentinosaurus and Puertasaurus, however, this seems to be an exaggeration for the known specimens. However, its transverse width is still greater than in Argentinosaurus, suggesting a proportionally wide ribcage.

I initially had a loose guess that this creature would turn out ~35 metres long or more before this skeletal reconstruction, but after working on it, I figured that this may be a bit excessive for the known specimens. However, given that the holotype has an unfused scapulacoracoid and that bone histology analysis found the known individuals to be subadults, adults would have grown larger than in these reconstructions. The schematic skeletal in the description was subpar to say the least, but it sufficed in very rough shapes for many of the bones.

The Patagotitan specimens were complete enough as a whole to base most of the proportions on other conspecific specimens rather than related taxa. The holotype MPEF-PV 3400 and paratype MPEF-PV 3399 were cross-scaled via the 8th dorsal, which overlaps between them in an uncrushed and unbroken state. MPEF-PV 3397 and the rest of the paratypes were composited into one and scaled down from the holotype reconstruction. The sacrum, ilium, lower hindlimb proportions, and humerus:femur proportions were based on Futalognkosaurus. Since illustrations of the caudals are quite scarce, and the description's schematic doesn't have them in a good-enough resolution to use, many of the caudals were roughly illustrated using Dreadnoughtus. The cervical count was reduced from the 15 used in the description to 14, based on Futalognkosaurus. And since the anterior dorsals were quite crushed, cross-scaled Futalognkosaurus dorsals were used to estimate their uncrushed lengths. The skull is a speculative transitional morph based on a cross between Tapuiasaurus, Malawisaurus, and Narambuenatitan.

The left and right femora in MPEF-PV 3399 and humeri of the MPEF-PV 3397 + other paratypes composite were swapped in the lateral view skeletals in order to show off the preserved and illustrated elements. Bones which are well-illustrated in the description or external photographs are in white, while bones which are unillustrated or poorly-illustrated are in light grey. Illustrated bones with unspecified specimens in the description's figures (such as the first caudal) are marked as illustrated in all specimens which preserve said bone.
_____

Measurements for MPEF-PV 3400:

Hip height: ~4.76 metres

Shoulder height: ~5.48 metres

Total height: ~13.21 metres

Standing length: ~26.5 metres

Axial length: ~30.82 metres
__

Measurements for MPEF-PV 3397 + other paratypes, scaled to MPEF-PV 3397:

Hip height: ~4.29 metres

Shoulder height: ~4.94 metres

Total height: ~11.9 metres

Standing length: ~23.88 metres

Axial length: ~27.77 metres
__

Measurements for MPEF-PV 3399:

Hip height: ~4.75 metres

Shoulder height: ~5.25 metres

Total height: ~12.33 metres

Standing length: ~26.83 metres

Axial length: ~30.79 metres
____

References/sources:

Carballido et al., 2017, "A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs"
Calvo et al., 2007, "Anatomy of Futalognkosaurus dukei Calvo, Porfiri, Gonzales Riga & Kellner, 2007 (Dinosauria, Titanosauridae) from the Neuquen Group(Late Cretaceous), Patagonia, Argentina"
Gomani, 2005, "Sauropod dinosaurs from the Early Cretaceous of Malawi, Africa"
Filippi et al., 2010, "A new titanosaur sauropod dinosaur from the Upper Cretaceous of North Patagonia, Argentina"
Wilson et al., 2016, "The skull of the titanosaur Tapuiasaurus macedoi (Dinosauria: Sauropoda), a basal titanosaur from the Lower Cretaceous of Brazil"
Calvo, 2014, "New fossil remains of Futalognkosaurus dukei (Sauropoda: Titanosauria) from the Late Cretaceous of Neuquen, Argentina"
Lacovara et al., 2014, "A gigantic, exceptionally complete titanosaurian sauropod dinosaur from southern Patagonia, Argentina"
Gonzalez-Riga et al., 2016, "A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot"
Greg Paul, 2016, "The Princeton Field Guide to Dinosaurs"
Scott Hartman's Futalognkosaurus
Patagotitan arm photo
Patagotitan femur photo 1
Patagotitan femur photo 2
Patagotitan mount photo 1
Patagotitan mount photo 2
Patagotitan mount photo 3
____

UPDATE(4/29/2018): Added detail, replaced the skull, and scalebar updated to my new conventions. See the previous version here for comparison.
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anonymous's avatar
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Pristichampsus's avatar
PristichampsusProfessional General Artist
I find it hard to believe that a reconstruction by actual paleontologists is wrong by 10 meters, and the rough reconstruction by an amateur on the internet can be correct in changing its size. I'm sorry, but this syndrome of reconstructions by unqualified amateurs on the internet only muddies the waters when thinking about the actual results given by actual scientists. If you have not worked with the actual material professionally, that docks off almost all credibility in my eyes. I will only ever trust Scott Hartman in this regard because he is so rigorous and professional, I don't even trust GS Paul anymore. But the mantra of actual museums is that the people who have seen the actual specimens and worked with them should be deferred to in almost all cases.

This is of course based on my assumption that you are actually not qualified as a PAleontologist, correct me if that is an error on my part.
SpinoInWonderland's avatar
How about actually reading the papers themselves and looking at the measurements of the bones before making ad verecundiam statements? Relying on literally only one skeletal reconstruction artist is a tad narrow-minded, sometimes you have to admit that others like GSP can get things right as well. Putting all your eggs in one basket is not a good idea.

I did defer to the people who have seen and worked with the specimens - Carballido et al. (2017) is cited right there in the references list. How about cross-checking my reconstruction with the published bone measurements rather than relying on author authority as your prime argument? Checking the credibility of a reconstruction means checking it against the data, not the author. Go check out the Carballido et al. (2017) papers and its individual bone measurements, then come back and tell me exactly what's wrong with my reconstruction.

I never claimed that my reconstruction is necessarily the correct one, like all restorations of incomplete taxa it is subject to some educated guesswork and estimates for total dimensions could vary quite easily. But try scaling those bones as per the Carballido et al. (2017) measurements and put them in a 37-metre animal, and you won't need a palaeontologist to see how that works out.

I hope you realise that Scott Hartman has made at least a few mistakes as we all do. His Cedarosaurus is very incongruent with the actual published measurements (Benson et al. 2014 lists the humerus of DMNH 39045 at ~1.38 metres long, while it is almost ~1.8 metres long in Scott Hartman's) and his AMNH 5027 omits the fused D7-D8 as illustrated in Osborn's 1917 osteology, for example.

If you're so convinced by the 37-metre Patagotitan and you rashly placed all your eggs in the Scott Hartman basket, how about asking him what he thinks about the mount?

And if you're such a stickler about credentials, let me tell you this - the curator of the Denver museum, Joe Sertich, thinks my skeletal reconstructions are professional-level and even offered to have me create a few skeletals for a few taxa currently in embargo (so please don't ask about them right now). I declined due to my poor skeletal-reconstruction-related time management, but he was impressed by them while I was being humble about it. Just food for thought.
Pristichampsus's avatar
PristichampsusProfessional General Artist
Wait, so you accuse me of argument from authority, and then claim your own credibility from authority too. Good for you that you are good enough to get work, but you're sort of shooting yourself in the foot if you accuse me of argument from authority.

I only defer to the original description because I am not smart or skilled enough to check the measurements against the actual reconstruction. I think I have every right to be skeptical of any unqualified person who makes a reconstruction, at my own discretion. Maybe I am arguing from authority, but as I said, I have neither the patience or the skill to do this myself, but I have every right to be skeptical. And my mantra about deferring to those that have seen the actual specimens is ABSOLUTELY what they do at museums, it's why we have the main authority on Ediacaran fossils here in South Australia, as opposed to some chump who looks at casts and assumes they were lichens or some shit.

I am sorry, work with the material, have qualifications, be more rigorous than just reading a paper. Those are my caveats for accepting a reconstruction. Yours might be right, but I have no standard to judge that against besides the fact that you are not a qualified paleontologist.

Again, I am not claiming to know better than you, and I am perhaps arguing from authority. But pretty much anyone can put spin on anything on the internet, and I prefer sticking to people with credentials, and the consensus.
SpinoInWonderland's avatar
The end paragraph about credentials was only icing on the cake, it was not my main point. To claim my own credibility from authority would be to say that my reconstructions are automatically credible simply because an authority expressed approval of them, which is something I did not argue for at all. My core point is that checking the credibility of a reconstruction means checking it against the data rather than the author, and that placing all your eggs in a single skeletal artist's basket is generally not a good idea.

You didn't defer to the original description, you deferred to the mounted skeleton - there are no reported total body dimension estimates from the Carballido et al. (2017) paper or its supplementary data. While you have a right to be skeptical (a healthy amount of skepticism is good), you are outright admitting that you are relatively uninformed here and thus have little basis for judging the reconstruction besides relying on author authority.

There is no consensus on Patagotitan's overall dimensions (a single mount doesn't exactly count as a consensus) and, once again, the people with credentials who worked on the material has already been deferred to via their published data. It's not like I have to directly ask them about how big certain bones are (and which ones are deformed or crushed) when they already gave this data away themselves. Thus, I'm not exactly seeing the point of repeating that mantra here, I'm not deferring to some random chumps as references for anything here. I am well aware that "pretty much anyone can put spin on anything on the internet", but you test them by checking against the data, once again, not the authors of said reconstruction.

I'm not asking you to necessarily agree with my reconstruction, but this critique simply isn't pointed at the actual reconstruction itself. I did ask Scott Hartman about his thoughts on the mounted skeleton, in any case.

And, just curious, what are your reasons for your distrust of GSP?
Pristichampsus's avatar
PristichampsusProfessional General Artist
I was not aware that the actual paper did not have any size estimates. The fact that it is only the mount does complicate things. Again, I am not skilled enough to do the numbers myself, maybe I was rash by trusting the one reconstruction, but trusting the experts or consensus is generally how I do this sort of thing.

I am only really saying that you would have more authority with this reconstruction if you had actually worked with the specimens. Measurements in papers can be wrong, to the extent of not even matching their own reconstruction, so I still think firsthand experience is best.

The only thing I am bemoaning here, is that there are lots of interested amateurs that are making reconstructions that they claim are correct and that the authors estimates are wrong. And in that case I will inevitably defer to the people who have qualifications and firsthand experience.

My main problem with GSP is 2 things. 1- His taxonomy stinks, he synonomizes genera based on one or two shared features, such as Monolophosaurus and Guanlong, and he is blinkered by his pet hypotheses about volant Maniraptoran ancestors, to the point that parts of his book are almost useless. 2- I have discussed with another person on here that sometimes he seems to draw teeth too small and this may effect some of his estimates. He once estimated a large T-rex based on a single tooth, and if he draws teeth too small that estimation would be way off.
SpinoInWonderland's avatar
"I was not aware that the actual paper did not have any size estimates. The fact that it is only the mount does complicate things. Again, I am not skilled enough to do the numbers myself, maybe I was rash by trusting the one reconstruction, but trusting the experts or consensus is generally how I do this sort of thing."

It's fine.



"I am only really saying that you would have more authority with this reconstruction if you had actually worked with the specimens. Measurements in papers can be wrong, to the extent of not even matching their own reconstruction, so I still think firsthand experience is best."

That I can agree on, but for most of us (including most palaeontologists), the paper is the best we've got. Generally, if their measurements mismatch with a drawn reconstruction in the paper, the measurements tend to be correct more often since it's easier to draw bones and scalebars too large or too small than it is to misuse a tape measure.



"The only thing I am bemoaning here, is that there are lots of interested amateurs that are making reconstructions that they claim are correct and that the authors estimates are wrong. And in that case I will inevitably defer to the people who have qualifications and firsthand experience."

Don't worry, I'm not that kind of person, claiming absolute correctness on what is an educated guess most of the time is a no-no, any expert worth their credentials will tell you that.



"My main problem with GSP is 2 things. 1- His taxonomy stinks, he synonomizes genera based on one or two shared features, such as Monolophosaurus and Guanlong, and he is blinkered by his pet hypotheses about volant Maniraptoran ancestors, to the point that parts of his book are almost useless. 2- I have discussed with another person on here that sometimes he seems to draw teeth too small and this may effect some of his estimates. He once estimated a large T-rex based on a single tooth, and if he draws teeth too small that estimation would be way off."

I think you're referring to his 1988 book Predatory Dinosaurs of the World for the weird taxonomy and the supergiant T. rex bits, both of which he has since mostly rescinded ("mostly" as his 2016 PFG still has some odd taxonomy). His 2016 edition of The Princeton Field Guide to Dinosaurs shows his more updated viewpoints, which, I have to admit, still comes with problems such as anteroposteriorly compressed T. rex and continued adherence to shrinkwrapping.

Scaling based on teeth by itself is very problematic with dinosaurs no matter who does it, they vary massively in size within the same mouth too much to be used for any semi-decent scaling, the error bars would be huge beyond belief.
Pristichampsus's avatar
PristichampsusProfessional General Artist
Okay, I am glad we did not have too much animosity over this.

And for what it's worth, now that you explained how rigorous you are, I may as well chalk you up with Scott Hartman and GetAwayTrike and Miyess as skeletal artists that I trust. Incidentally, seeing as this guy comes down to 30 in your recon, what ACTUALLY could be the biggest or longest dinosaur? And what part of the body loses out when you did this recon? Did the original have too much tail or torso or what? I did notice you used Hartman's Alamosaurus as a rough base, which probably makes a lot of sense.

As I said, I am just leery of amateurs with an axe to grind, and they do exist. There was a chap that kept saying that Amphicoelias was insanely large based on what he supposed was an inaccurate measurement or decimal point or some nonsense. And there are people out there that have pet hypotheses etc that don't stack up.

Anyhow, peace-out.
SpinoInWonderland's avatar
:) (Smile)

"what ACTUALLY could be the biggest or longest dinosaur?"

The simple answer is that we don't know. The main problem is that we barely have anything from the truly gargantuan dinosaurs, a lot of them are quite fragmentary. Then there's the fact that we have barely scratched the surface of Mesozoic biodiversity, there could be some more ultra-gigantic taxa out there that we have no idea about. Based on the known fossils Maarapunisaurus has the largest known axial element while Argentinosaurus has the longest known femur, but this is merely based on the few and fragmentary samples recorded so far.



"And what part of the body loses out when you did this recon? Did the original have too much tail or torso or what?"

From the looks of it, the mount has an extreme amount of caudals (something like 80+?) and 15 cervicals. I reconstructed the critter with a standard count of 50 caudals (most sauropods usually get within the range of ~40-65, diplodocoids are the exception) and 14 cervicals based on the complete cervical series of Futalognkosaurus. The sacrum is also restored much smaller than in the mount, based on Futalognkosaurus. So a little bit of neck, quite a bit of hip, and a lot of tail.



"I did notice you used Hartman's Alamosaurus as a rough base, which probably makes a lot of sense."

Futalognkosaurus, not Alamosaurus :D (Big Grin)



"There was a chap that kept saying that Amphicoelias was insanely large based on what he supposed was an inaccurate measurement or decimal point or some nonsense. And there are people out there that have pet hypotheses etc that don't stack up."

I have no idea why they would need some weird mental gymnastics to make Maarapunisaurus (I assume they meant "A. fragillimus") larger. I mean, it's already insanely large by itself, it had the largest known vertebra on record! The fact that even that didn't satisfy their size boner is an indicator of the unfortunate state of certain individuals regarding animal sizes. It's like those people desperately wanting 30-metre megatooth sharks or 150-tonne pliosaurids, the real animals themselves are already large enough and there's no need to force them to be kaiju.
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Paleonerd01's avatar
Paleonerd01Hobbyist Traditional Artist
Do you know what the diameter of the caudal vertebrae for MPEF-PV 3399 is? 
SpinoInWonderland's avatar
Based on the measurements from the Carballido et al. (2017) supplementary data, the first caudal centrum is about 36 centimetres wide and 46 centimetres deep at the posterior end, the middle caudal centra (19th-30th) are around ~20-33 centimetres across, and the distal caudal centra (36th-44th) are about ~13-16 centimetres across.
Paleonerd01's avatar
Paleonerd01Hobbyist Traditional Artist
Thank you very much i appreciate it greatly, one more question if you don't mind, do you know what the diamante of the caudal vertebrae of 3400 is? 
SpinoInWonderland's avatar
Based again on the Carballido et al. (2017) supplementary, the first caudal is about 33 cm long and 40 cm deep, the 3rd and 4th caudals are about 44 cm deep with no listed width, 5th is about 29 cm wide and 36 cm deep, 7th is about 37 cm wide and 40 cm deep, and the 8th is about 32 cm wide and 34 cm deep.
Majestic-Colossus's avatar
I wonder how some people got only ~5m at the scapula for the biggest specimen, given that we have a pretty good idea of how long its arms were and such.
SpinoInWonderland's avatar
It's because they simply composted the MPEF-PV 3397 humerus into MPEF-PV 3400/MPEF-PV 3399 despite MPEF-PV 3399 being an isolated element that lacks any overlap with MPEF-PV 3400/MPEF-PV 3399, rather than actually trying to cross-scale to figure out an estimated femur length for the specimens.
ForbiddenParadise64's avatar
Nice to see a robust titanosaur model that isn't just based off the museum mount with its absurdly narrow torso (even *Diplodocus* didn't have a torso narrower than the pelvis) and Diplodocus like head. The latter is where the 44 and 55 tonne estimates come from. 
SpinoInWonderland's avatar
The head in the mount isn't anything like a Diplodocus head, it's a cross between a duckbill and a pseudo-nemegtosaur head ;) (Wink)

s1.ibtimes.com/sites/www.ibtim…
JonaGold2000's avatar
JonaGold2000Hobbyist Traditional Artist
Where did you get the ribs, femur sideview, forearms, ischium, pubis, illium, manus, and the shapes of the anterior dorsals? The forearms, ribs, illium, ischium, pubis and femur are all only available in pictures of the mount and they dont resemble said mount very much. The vertebrae dont look anything like the ones figured, I know theyre poorly illustrated and sometimes crushed but that is no excuse for this level of discrepancy.
And thats not even mentioning your rejection of the phylogeny out of no other reason than you not liking the conclusion.
SpinoInWonderland's avatar
For the ribs, forearms, pubis, ischium, and unillustrated dorsals, it's in the description here itself:

"The schematic skeletal in the description was subpar to say the least, but it sufficed in very rough shapes for many of the bones."

Ilium is based on Futalognkosaurus. Did you just hastily skim through the text here?

The lateral view of the femur is generic. Manus was copy-pasted from the ones I already used in my longkosaur skeletals.


"The vertebrae dont look anything like the ones figured, I know theyre poorly illustrated and sometimes crushed but that is no excuse for this level of discrepancy."

What do you mean? If you're talking about the ones illustrated in detail here, I merely corrected for crushing, breakage, and distortion. Care to elaborate?


"And thats not even mentioning your rejection of the phylogeny out of no other reason than you not liking the conclusion."


It's not a matter of just "not liking the conclusion", it's that it's generally inconsistent with the few consistent things Titanosauria had:
  • Almost all analyses had aeolosaurids at least close to Saltasauria if not part of it AFAIK. They're known from extensive material as well, not much gaps. How did that get moved from it's consistent and repeated placement suddenly into longkosauria just because of one taxon?
  • How did Argentinosaurus get thrown into derived longkosauria all of a sudden? Argentinosaurus consistently scored as a basal titanosaur in most analyses, and it's not like the Argentinosaurus material we have somehow increased without anyone ever reporting on it.

In any case, it won't change anything in this reconstruction aside from the head.

JonaGold2000's avatar
JonaGold2000Hobbyist Traditional Artist
"The schematic skeletal in the description was subpar to say the least, but it sufficed in very rough shapes for many of the bones."
You say this but it's not seen in the results, and trust me I read the description.

"What do you mean? If you're talking about the ones illustrated in detail here, I merely corrected for crushing, breakage, and distortion. Care to elaborate?"
The anterior dorsals particularly don't resemble the figured ones at all.

"It's not a matter of just "not liking the conclusion", it's that it's generally inconsistent with the few consistent things Titanosauria had:
  • Almost all analyses had aeolosaurids at least close to Saltasauria if not part of it AFAIK. They're known from extensive material as well, not much gaps. How did that get moved from it's consistent and repeated placement suddenly into longkosauria just because of one taxon?
  • How did Argentinosaurus get thrown into derived longkosauria all of a sudden? Argentinosaurus consistently scored as a basal titanosaur in most analyses, and it's not like the Argentinosaurus material we have somehow increased without anyone ever reporting on it.

In any case, it won't change anything in this reconstruction aside from the head."
You're rejecting the phylogeny purely based on the results, I've heard no critique from you about the actual methodology, just that the results are not what expect and therefore wrong. The inclusion of a new complete taxa will do that to an unstable clade. Even if there are some relatively complete taxa already.

SpinoInWonderland's avatar
"You say this but it's not seen in the results, and trust me I read the description."

It's the combined effect of shape refinement (so it doesn't look like a mess, e.g. giving the neural spine shapes a smoother series progression, etc.) and converting a dirty low-res pixellated shape into a clean high-resolution outline. Rough and basic, not exact.


"The anterior dorsals particularly don't resemble the figured ones at all."

Seeing from the figures that the 2nd dorsal basically looks as if it were squashed by a steamroller anteroposterorly, and every dorsal from the 1st to the 3rd were compressed, I used Futalognkosaurus dorsals cross-scaled via the 5th dorsal (the anteriormost uncrushed dorsal) to roughly estimate uncrushed lengths for them. I then stretched the D2 lateral view figure to that length and corrected some remaining distortion, such as the squashed anterior ball, decompressing it using Puertasaurus and Pitekunsaurus as rough guides. As for the front view, I just looked for the side that has longer transverse processes (since that's the side less likely to be crushed, crushing usually doesn't extend transverse processes but can easily compress them) and mirrored it, then corrected some remaining asymmetrical distortion. As for the 3rd dorsal, I restored it's neural spine based on the 2nd dorsal rather than taking it from Argentinosaurus like the paper did (which caused a sudden and abrupt shape difference between the D2 and D3 neural spines), as you would reasonably expect a neural spine's shape to not differ too drastically from the ones just adjacent to it in the series.


"You're rejecting the phylogeny purely based on the results, I've heard no critique from you about the actual methodology, just that the results are not what expect and therefore wrong. The inclusion of a new complete taxa will do that to an unstable clade. Even if there are some relatively complete taxa already."

It's just another titanosaur analysis, just another one. And one I'm not very convinced of since it, as I said, generally inconsistent with the few consistent things Titanosauria had over more than 2 decades of phylogenetic analyses. Argentinosaurus being a basal form was repeatedly found in analyses consistently. Aeolosaurines being close to Saltasauria was repeated numerous times and consistently at that. They stood the test of time well. I don't think one new analysis short of the ones on the scale Tschopp and co. do would topple all that alone. Futalognkosaurus is more complete than Patagotitan, and it failed to bring stability to the clade. The numerous titanosaurs more complete than Patagotitan and even Futalognkosaurus (mostly saltasaurs AFAIK) didn't do that either. Now, I'm not saying that everyone who uses it is wrong, if you're convinced by it, it's fine, but I don't recommend taking every single new titanosaur analysis at face value.

As for using Tapuiasaurus skulls for longkosaurians, that was from a time when I was less aware of Titanosauria's instabilities and due to my awareness of it by now, I just don't feel safe swapping that every time Titanosauria transforms it's tree again. It's just something that happened to have stayed rather than something I have a strong conviction towards.
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