Largest mosasaur

[theropod]

Yeah. It’s a huge specimen, but that doesn’t make their size estimate valid unfortunately. There’s no guarantee recent studies take into account all the information.

What would be good is a revision of mosasaurs as a whole, including comparisons among the largest specimens and differences in proportions within the family. It would be good to see the actual material these ratios base on described in detail.

I knew it had been posted somewhere, but I couldn’t remember where when I stumbled across the abstract, so I reposted it.

[coherentsheaf]

When we are at it, can someone please try to cross scale the picture of the quadrate I posted? t seems to be a serious conteder for largest mosasaur.

[theropod]

Unfortunately I couldn’t find a measurement, so I had to use the scalebar. For what it’s worth, here’s my result:



I would have measured it earlier had I had the paper. I’m afraid the reliability of this is questionable at best, because it bases on a scalebar, but our scaling seems to agree, and it’s consistent with the claim of giant size.
If this restoration and scalebar are accurate, NHMM 603092 belonged to a skull approaching 2m in lenght.
But some further reading here as to why the specimen seems to actually be smaller than it my scaling makes it appear: theworldofanimals.proboards.com/post/29472
The quadrate as scaled here here ends up a tad large, the real measurement is  about 94% the size and would result in a 1.83m skull lenght based on this reconstruction alone. Since another specimen has a proportionately larger quadrate, this seems to be be down to the proportions being different, or maybe plain wrong, in this reconstruction of the skull.

Btw what is that supposed 145cm skull cited by Fanti et al. (on the big Italian specimen)? I’ve checked the paper I couldn’t find it, only a mandible lenght of 160cm which would indicate a 151cm skull using the above proportions.

[blaze]

It does seem to suggest an skull some 2m long... if the scalebars are accurate.

[creature386]

This would make 16 to 17 m possible. I just measured it by myself because I first couldn't believe it, but I can confirm it now.

[theropod]

Maybe blaze could make a rigorous size comparison of the largest specimens of Tylosaurus (KUVP 5033 and the huge dentary from page 1), Prognathodon (curii and saturator), Hainosaurus and Mosasaurus (NHMM 603092, this guy→ and maybe for comparison the specimen with the 160cm mandible) and the Italian mosasaurine described by Fanti et al..

[theropod]

Overall I have to say this is really impressive, this thread now contains a number of individuals probably larger than the commonly cited largest mosasaur specimens.

[theropod]

journals.cambridge.org/action/displayAbstract?fromPage=online&aid=9364812&fulltextType=RA&fileId=S0016774614000274

[creature386]

I did not even know that the most famous Mosasaurus specimen (M. hoffmanni) is disputed, but nice to see that the paper supports it.

[blaze]

The skulls are somewhat crushed but the dentaries appear undistorted... now on topic, the dentary shared in the first page, I think this serves rather as an upper bound because the specimens I'm comparing the dentary against have jaw lengths of only about 1m, comparing it to what appear to be larger specimens (1) the dentary appears to get deeper (decreasing possible jaw length to 160cm) also, the photo of the dentary is not in perfect lateral view as we can see a bit of its dorsal surface so that might also bias to scale it larger.

Based on a complete Tylosaurus proriger specimen (jaw length 123cm, total length 8.8m, ratio of 1:7.1) we get an estimated total length of 11.5-12m, I wonder if Bunker's size claims are like this, not skull but jaw length of almost 6ft (5.5ft is good enough for that claim).

[Grey]

Two new evidences for giants Mosasaurus and one debunked :

From Mike Everhart.



here is the photo of the partial right dentary (medial view) of a very large Mosasaurus that was published by Meijer, 1971 (….. and not Meijer, 1983, as cited by Lingham-Soliar, 1995). It is 90 cm in length, with positions for 10 teeth, some of which are reconstructed. The specimen is currently on display at the Natuurhistorisch Museum, Maastricht, The Netherlands. Thanks to John Jagt for the article (1 page) and background information.

How large would be the skull of that specimen ?

Another pic :




In a private discussion, Everhart also debunked Lingham-Soliar claim about the fragment that Lingham-Soliar used as evidence for a 17.6 m mosasaur.

Having seen Meijer 1983 for the first time today, a rough translation of his opening paragraph is: "The fossil, which is included in the collection of the Natural History Museum Maastricht under no. NHMM 198349, is 33 cm long, and is 2.7 cm high at the sixth tooth from the front ('tooth position 6').
In comparison, the corresponding length, for the well-known 'Paris exemplar' of Mosasaurus hoffmanni is about 75 cm."
=============================
Meijer, A.W.F. 1983. De vondst van een onderkaaksbeen van een onbekende Mosasauriër (Reptilia, Mosasauridae) in de Sibbergroeve. Natuurhistorisch Maandblad 72(12):269-271.
The specimen number is wrong, the length is wrong (definitely NOT 900 mm (90 cm) and there is NO Figure 3 in the Lingham-Soliar discussion.


But Everhart considers Grigoriev Russian specimen as legit claim for a 17 m mosasaur.

[blaze]

I got confused, is the 90cm fragment the same as the 33cm one?

Regarding the Russian Mosasaurus, what are Everhart reasons? Grigoriev (2014) clearly says that he bases his estimate on "using Russell’s (1967) length of the M. hoffmanni jaw as equal to 10% of the overall body length" but this seems to be just a guess on Russell's part and in all large mosasaurs (Tylosaurus, Hainosaurus) such percentage is over 13%, in fact, a mandible length of 170cm corresponds to an skull length of 1.6m (or 1.5m at midline) which is the same or less as in the mostly complete Hainosaurus bernardi IRScNB R23 which Lindgren (2005) estimates at 12.2m.

[elosha11]

Wow some great finds here. Without reading through the whole thread, what would be the rough weight estimate for a 17 meter mosasaur? They were relatively elongated and flexible animals. 30-40 tons perhaps? I would think they'd be a bit lighter than comparably long whales or mega-toothed sharks.

[Deathadder]

I would say 15 to 25 tons. But that's just my guess.

[Deleted]

Jun 27, 2015 10:30:42 GMT 5 elosha11 said:

Wow some great finds here. Without reading through the whole thread, what would be the rough weight estimate for a 17 meter mosasaur? They were relatively elongated and flexible animals. 30-40 tons perhaps? I would think they'd be a bit lighter than comparably long whales or mega-toothed sharks.

30-40 tonnes is way over the top for any known mosasaur, even for a ~17-meter one.

More like roughly around ~15-16 tonnes assuming that a ~14.2-meter Tylosaurus had roughly the same volume as a Giganotosaurus.

To get one at ~30-40 tonnes you'll need to get it to lengths roughly around ~21.2-23.3 meters or so.