Megalodon size

[prehistorican]

I see, so more straight and muscular gills?

[prehistorican]

May 23, 2018 21:12:02 GMT 5 Grey said:

Leedsicthys is usually considered as the largest bony fish.

Ferrón 2018 suggests its maximum theoretical body mass to be 44.9 tonnes.

This is indeed below than megalodon body mass predictions which are 48-103 tonnes (Gottfried 1996) for a 16-20 m shark but a similar work from Randall could suggest as well 34-74 tonnes, 100 000 pounds (Renz 2002) for a 18 m individual or 50-60 tonnes for a 18-19 m meg(Siversson 2012, lecture talk).

Even favoring the lower estimates would suggest larger mass estimates for meg, the largest predicted body mass for any macropredator, it would appear to be heavier than the biggest possible ectotherm bony fish.

But I'd like to see Ferrón et al. performs a similar work on megalodon than what they did for Leedsichthys.

Do you believe that Megalodon was bulkier than a white shark? I think it was.

[Grey]

Jun 3, 2018 6:05:04 GMT 5 prehistorican said:

May 23, 2018 21:12:02 GMT 5 Grey said:

Leedsicthys is usually considered as the largest bony fish.

Ferrón 2018 suggests its maximum theoretical body mass to be 44.9 tonnes.

This is indeed below than megalodon body mass predictions which are 48-103 tonnes (Gottfried 1996) for a 16-20 m shark but a similar work from Randall could suggest as well 34-74 tonnes, 100 000 pounds (Renz 2002) for a 18 m individual or 50-60 tonnes for a 18-19 m meg(Siversson 2012, lecture talk).

Even favoring the lower estimates would suggest larger mass estimates for meg, the largest predicted body mass for any macropredator, it would appear to be heavier than the biggest possible ectotherm bony fish.

But I'd like to see Ferrón et al. performs a similar work on megalodon than what they did for Leedsichthys.

Do you believe that Megalodon was bulkier than a white shark? I think it was.

Possibly, at least the jaws were certainly more massive at parity size. No necessarily though. That's why predicting 40 tonnes or 70 tonnes for a 18 m indivual is equally plausible at this point based on the data of Gottfried and Randall, respectively.



theropod, I'd need your opinion on the possible position(s) of that specimen (if you have some time to spend for it).





theropod now ?

[prehistorican]

I think the second one is the giant Summerville specimen. Anways scaling 2.236t great white for 6m Deep Blue gives a reasonable 60.3t for an 18m individual.

[Grey]

It is the same tooth in all the three pictures but yes it is a Summerville specimen owned by a Belgian collector. You know it ?

That is reasonable. It depends also if meg had a liver proportionately as heavy.
It is possible as well meg was slightly slimmer in order to be faster at such sizes but this could be in contradiction with the massive weight of the whole dentition which necessitates a strong structure for support...

[theropod]

Grey The images don’t show.

[Grey]

theropod, done.

[theropod]

I would say either 8th-9th upper (L5-L6) or 7th-8th lower (l4-l5)

[Grey]

Aug 6, 2018 23:52:17 GMT 5 theropod said:

I would say either 8th-9th upper (L5-L6) or 7th-8th lower (l4-l5)

Relying on this range of possible positions using crown width of this tooth (123 mm; source : the owner) and comparing with our mean estimate for the Aurora specimen would suggest a minimum TL of 18 m, a maximum of 24.4 m for a mean TL from all the positions of 21.7 m.

[elosha11]

Grey, I don't suppose the owner would be willing to send you pictures of this tooth being measured at 123 mmm? That would be ideal.

[prehistorican]

I think Megalodon might be a slightly more robust than people give it credit for.
www.eonline.com/news/533540/meet-joan-of-shark-quite-possibly-the-biggest-great-white-shark-ever-discovered
So a 4.877m shark at 1.633 tonnes? Quite a robust animal when you scale it up.

[elosha11]

^ Well to be fair, there are other GWS around the same length and weight as Prehistorian first posted about Joan of Shark. There's an immature female listed at 4.76 meters and weighing 1628 kgs. But of course there are also sharks listed around the same length that weigh substantially less. See elasmollet.org/Cc/Cc_list.html. On the same website there are four sharks measuring from 5.3m, 5.7m, 6.7m and a large shark of unknown length, and each weighed or was estimated at 2500 kgs. GW shark weights can vary greatly by individual.

There was a shark of 17.7 ft/5.39 meters feet that weighted 4140 pounds/1877 kgs. www.sharkresearchcommittee.com/dist.htm

Commercial fisherman Joe Friscia captured an adult female White Shark in his drift gill net on 18 September 1985, about 15 miles southwest of Point Vicente, Los Angeles County, California. The shark was 17 feet 7 inches in length and weighed 4,140 pounds. The accuracy of the shark's weight is indisputable. The 'truck scale' used to weigh the shark was checked by the California Department of Weights and Measures and found to be accurate to within ± 5 pounds. When the shark's stomach was dissected it was found to contain the remnants of two pinnipeds — an adult Harbor Seal (Phoca vitulina) and a 'roto tagged' juvenile Elephant Seal (Mirounga angustirostris). Examination of the shark's jaws revealed three individual rows of upper lateral teeth to be anomalous. Upon closer scrutiny, over a dozen stingers of Bat Rays (Myliobatus californicus) were found imbedded in the shark's upper and lower jaws. Several of these stingers had penetrated tooth germ sites (the area of the jaw where tooth formation occurs), causing permanent damage to these three individual teeth. Several of the stinger wounds were recent, suggesting that this shark had fed not only on pinnipeds but also on benthic (bottom-dwelling) Bat Rays (Photograph courtesy Gordon Hubbell).

.

I imagine that Megalodon sharks showed similar variation between individuals.

[Grey]

So I was able to facetime with the current owner of the Bertucci jaws reconstruction and he gave me measurements of one side of the first upper row of the dentition.

Like I suspected, when compared with the decreasing size of the Yorktown dentition, the Bertucci composite is actually accurate and even surprisingly conservative, at least for this row.

The summed width of this row appears to 1359 mm with the first upper being 139 mm in crown width.

The Yorktown set is 1147 mm in summed width with the first upper being 108.5 mm.

If I scaled the summed width using the respective first upper, I would have get a summed width of 1469 mm.

Thus, contrary to what said Ken Shimada (who is more experienced in the proportions of Carcharodon dentitions), the Bertucci reconstruction is not exaggerated in the size of each tooth position, it is even noticeably conservative, at least this particular side of the jaws.

[Grey]

Interesting example about how much the discrepancy can exist between average size and maximum size in sharks.



This female mako had an estimated length of 585 cm. The previous record max size was 445 cm.

[Grey]

The first pics of the model, actually 52 feet long, 22 feet pectoral width, will be available Thursday or Friday.

The model could weigh the 48 tonnes estimated by Gottfried at this length, a bit on the high end according to Hans Sues.

The set of teeth is based in size on the larger dentition on Bone Clones.