Largest mosasaur

[Verdugo]

theropod
It's all good but how did Broly get the 12.5 m Total length for Penza specimen? I tried to scale the mandible to 1.7 m in length and i can only get 12.2 m Tl. Using the original scale bar provided by PWNZ3R-Dragon (Penza is scale bar B), i still can only get 12.2 m Tl. Any idea?

Anyway, when adjusted back to 12.2 m Tl, i got a Body mass of 9.4 tonnes

[theropod]

Just checked and I’m getting 12.2 m too.

[theropod]

Since I don’t have the files of my old estimate but only the rounded figures from the comment, I’ve tried to replicate it:



So I’m getting very similar figures again. Around 9 t for a 12.2 m (measured tip-tip) M. hoffmanni, consistent with the size of the lower jaw from Penza, seems reasonable.

Attachments:

[Verdugo]

^ Is that a new model? The mass is actually slightly lower the your previous one (when scaled to 13.1 m using 2/3 factor i got only 8000 l vs 8700 l of the old one), i suppose the new one matches P-Dragon's skeletal more closely? (the chest from the old one does seem a bit too deep).

Anyway, seems pretty good. It's actually only slightly longer than that of Hartman's Tylosaurus (around 12 m) when scaled to 1.8 m mandibular length (i assume the 1.8 'skull' length is probably mandible) though being quite a bit more massive (9000 kg vs 6900 kg)

[theropod]

Yes, new model.

The difference really isn’t much though. I’d obviously go with the most recent one as that’s the one I just checked and have confidence in, but the original model scaled to 12.2 m would give 6.7 m³, this one gives 6.50 m³ with the same correction factor. Now assume the 13.1 m was rounded from 13.14, and the 8.3 m³ was rounded from 8.25, and we’d get down to 6.60 m³.

Even adjusted back to CF=0.93 and scaled to 12.2 m, that’s the difference between 9.06 t and 9.32 t.

A difference of 2-3% in overall volume really doesn’t surprise me at all for two models created independently. As you can see there’s a slight difference in how I modeled the tail, and there might also be a slight difference in how wide I scaled it, or a slight difference in how deep I modelled the torso, any of those could easily add or subtract 100-300 kg at these scales (and that’s the minimum margin of error we should always keep in mind for such estimates). For all intends and purposes, these two models are almost identical.

[wigglywaffles]

So then how large would the biggest mosasaur be from the data we do have? Also what is the exact formula you are using to get the length?

[Grey]

Got some informations from Anne Schulp.

Many thanks for your note.
I think the "Bunker" Tylosaurus KUVP 5032 was reconstructed at 15,8 m.
The Hageman specimen in Maastricht, NHMM009002 came in at 17,6 m according to our calculations (that's a big one already); the NHMM 003892 quadrate is a bit larger so the 20 m ballpark looks certainly feasible. Most M. hoffmanni are in the 13-14 m ballpark, so that's where the c. 150% comes from.
We don't have a publication in the works on the entire symposium contribution, but the 603092 specimen is certainly on the list of stuff-to-publish at some point.
The c. 1/9 or 1/10 skull/whole length ratio looks fine for M. hoffmanni. In Prognathodon the ratio is a bit different though; bigger skull, relatively speaking.
I do not have the precise 603092 measurements here.
Hope this helps nonetheless!
Kind regards -
Anne Schulp


With this in mind, the idea that mosasaurs maximum size did not show any plateauing toward the K-Pg boundary and the (optimistic but not implausible) possibility that quadrate NHMM603092 came perhaps from a ~3 m mandible, maybe really huge near-Hollywood sized mosasaurs are not so much fictional, especially as Sander et al. 2022 suggests that 20 m-ish hypercarnivorous marine reptiles were already possible in the Early Triassic.
Looks forward to see more publication regarding NHMM603092.

[Life]

May 19, 2022 19:26:08 GMT 5 Grey said:

Got some informations from Anne Schulp.

Many thanks for your note.
I think the "Bunker" Tylosaurus KUVP 5032 was reconstructed at 15,8 m.
The Hageman specimen in Maastricht, NHMM009002 came in at 17,6 m according to our calculations (that's a big one already); the NHMM 003892 quadrate is a bit larger so the 20 m ballpark looks certainly feasible. Most M. hoffmanni are in the 13-14 m ballpark, so that's where the c. 150% comes from.
We don't have a publication in the works on the entire symposium contribution, but the 603092 specimen is certainly on the list of stuff-to-publish at some point.
The c. 1/9 or 1/10 skull/whole length ratio looks fine for M. hoffmanni. In Prognathodon the ratio is a bit different though; bigger skull, relatively speaking.
I do not have the precise 603092 measurements here.
Hope this helps nonetheless!
Kind regards -
Anne Schulp


With this in mind, the idea that mosasaurs maximum size did not show any plateauing toward the K-Pg boundary and the (optimistic but not implausible) possibility that quadrate NHMM603092 came perhaps from a ~3 m mandible, maybe really huge near-Hollywood sized mosasaurs are not so much fictional, especially as Sander et al. 2022 suggests that 20 m-ish hypercarnivorous marine reptiles were already possible in the Early Triassic.
Looks forward to see more publication regarding NHMM603092.

Interesting. Thanks for the share.

Specimen NHMM 603092 is mentioned in following source:

Lingham-Soliar, T. (1995). Anatomy and functional morphology of the largest marine reptile known, Mosasaurus hoffmanni (Mosasauridae, Reptilia) from the Upper Cretaceous, Upper Maastrichtian of the Netherlands. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 347(1320), 155-180.

"Mosasaurs were marine varanoid reptiles known exclusively from the Upper Cretaceous deposits. They spread rapidly throughout the major oceans of the world in a geologically brief period of 25-30 Ma during which time they evolved to great size. Although Hainosaurus bernardi (Lingham-Soliar 1992a), at approximately 15 m, is usually regarded as the largest mosasaur, an enormous almost complete dentary of Mosasaurus hoffmanni, NHMM 009002 (Meijer 1983, figure 3) measuring 900 mm (complete estimate = 1000 mm), suggests an even greater total size. The entire lower jaw is reliably estimated at 1600 mm. Using a 1: 10 head to body ratio (see Russell 1967, p. 210 for M. maximus) the length of the whole animal is estimated at 17.6 m, making it the largest marine reptile known. Huge size in M. hoffmanni is also indicated by isolated specimens of an enormous quadrate NHMM 603092 and humerus TSMHN 11252 (figure 9i,j)."



Specimen Penza (CCMGE 10/2469) is very large as well. This specimen is discussed in following source:

Grigoriev, D. V. (2014). Giant Mosasaurus hoffmanni (Squamata, Mosasauridae) from the Late Cretaceous (Maastrichtian) of Penza, Russia. Труды Зоологического института РАН, 318(2), 148-167.

"The overall length of the skull is more than 1700 mm (the length of the right posterior mandibular unit is 690 mm, the length of the left dentary is more than 1020 mm). Thus, the total length of the animal should be approximately 17 m (using Russell’s (1967) length of the M. hoffmanni jaw as equal to 10% of the overall body length). M. hoffmanni from the Penza is one of the largest mosasaurs ever known."

17 m total length (TL) is commonly suggested for largest specimens found in publications though.

Let us see.

[Grey]

Yes, this piece has been discussed before, it appears much larger than the quadrate in IRSNB R26 which represents a ~1.5 m skull. Hence the hypothesis of a ~3 m skull and a large whale-sized body.

[Infinity Blade]

Was 17.6 meters independently estimated by both Lingham-Soliar and Schulp et al.? Or are they just citing the same estimate?

Interesting to see that even paleontologists now seem to have no problem with a 1:10 head to body length ratio for Mosasaurus.

[Grey]

May 20, 2022 3:32:00 GMT 5 Infinity Blade said:

Was 17.6 meters independently estimated by both Lingham-Soliar and Schulp et al.? Or are they just citing the same estimate?

Interesting to see that even paleontologists now seem to have no problem with a 1:10 head to body length ratio for Mosasaurus.

Seems like an off-line calculation they made in their 2016 symposium but sadly nothing is published.

This body plan for Mosasaurus appears to be okayed by Schulp et al.

www.cgtrader.com/3d-models/animals/dinosaur/mosasaurus-hoffmannir

[Grey]

Well apparently, since all the big pliosaurs described the last two decades all end up at 10-13 m (but he might argue against), it seems like, JW hype helping, that Max Hawthorne has reported his fetish of blue whale-sized hypercarnivorous marine reptile with kaijuesque bite force on Prognathodon sp. This is more than one year ago and still nothing new so far.



Now to be fair, Hawthorne is what he is indeed but if he really has some cool material and wants to publish something genuinely spectacular, no problem with that but if he could also have the balls to have it and his other purpoted analyses being reviewed prior to any fantasy claim would be good as well.

But I doubt a guy writing about a kaiju pliosaur literally raping a wounded female megalodon would get that chance.

I suspect he has a serious problem with scaling.

[Grey]

An excerpt from google.books of Greg Paul next Princeton field guide book about the Mesozoic marine reptiles, out in october.

It appears he's downsizing quite a bit the largest ichthyosaurs. Other parts of the book are available on g.books.

Looking at my previous post, it looks like Max Hawthorne is not gonna appreciate Greg Paul's book.

[Infinity Blade]

I hope I don’t come across petty here, but I would like to request members to do this one thing before it becomes a problematic habit. Please try to keep this thread more about relevant information, as opposed to venting about non-professionals, as much as possible. This thread should be one for interesting discoveries, nuanced discussion, maybe some myth-busting (although we already have a thread dedicated to that), etc. I don’t like seeing this thread updated and checking it out, only for it to be about some nonsense Max Hawthorne has put out. It’s one thing that Hawthorne is not a professional paleontologist, but it’s completely another that he has long been established here as unscientific, unprofessional, and fanatical. Unless he were to say something that cites actual scientific evidence or at least isn’t fanatical, I don’t care what he has to say.

If you must vent about the likes of Hawthorne or debunk his crap, try to do it in the ‘false scientific claims rebuttal’ thread or the ‘laughable and ridiculous claims’ thread.

[elosha11]

Aug 2, 2022 4:38:24 GMT 5 Grey said:

An excerpt from google.books of Greg Paul next Princeton field guide book about the Mesozoic marine reptiles, out in october.

It appears he's downsizing quite a bit the largest ichthyosaurs. Other parts of the book are available on g.books.

Looking at my previous post, it looks like Max Hawthorne is not gonna appreciate Greg Paul's book.

I don't know Greg Paul, I assume he is a mosasaur, pliosaur, and/or ichthyosaur expert? Is he very credible and respected? I will say that his speculations about Megalodon seems to be quite inaccurate and not supported by most modern research, but if he's not a shark expert, I suppose that could be overlooked. What is his specialty and what is his resume as to published papers?

Does he make any predictions about the hypothetical enormous ichthyosaurs that are hanging out there as potentially the largest macro predators?