Megalodon size

[Grey]

I use published methods on unstudied large teeth.

The hypothetical I use is based on two very large great whites...in the purpose to envision very large megalodons.

I use hypothetical based on actual method (in which I do not have great faith, but I'm tired to repeat it).

But I don't use hypothetical based on assumptions instead

You're really more and more provoking to question my honesty despite all my posts where I show my cautiousness while discussing size in a great fish officially known by almost only its teeth...

[Life]

Their is no restriction at posting size estimations obtained from different "shark size estimation methods" offered by experts in reliable literature during discussions in this forum. Words such as realistic, probable, likely and vice versa have been introduced in English language for a reason; use them where necessary.

[Grey]

Chilean tooth specimen from Atacama desert.

Described in excess of 11,43 cm wide and 14 cm high.

Estimated TL by tooth width : in excess of 15,6 m TL.
Estimated TL by Gottfried regression : 13,3 m TL

Note : I highly doubt this represents an UA, more likely a UL, so Gottfried's regression is probably not reliable here and produces an underestimate. Jeremiah's result produces also a conservative estimate as this specimen is most likely not the larger and wider tooth in the dentition.

This is were Shimada's method should be usefull but determining the exact position as well as the crown measurements is tricky.

EDIT : I've asked to a fossil sharks teeth collector, he personnally expressed it to be an U3. Not the largest the dentition. So the sizes estimates here are certainly too small.

[theropod]

Why don't you think its an UA? It looks pretty symmetrical to me.

[Grey]

One slant is shorter and more curved than the other, and the ratio width/length is greater than in UA. I will verify it but sounds likely not an UA or at least an UA3.

[Grey]

Chile, Atacama : 16,23 cm long, 12,77 cm wide.

Gottfried regression : 15,3 m TL.
Jeremiah's formula : 17,5 m TL.




US, East Coast : 16,5 cm long, 12,82 cm wide.

Gottfried regression : 15,6 m TL.
Jeremiah's formula : 17,6 m TL.

[Grey]

Discovery reconstitution of C. megalodon scaled up at 18 m TL.



Coherentsheaf's work.

[Grey]

Cast of the complete dentition owned by Gordon Hubbell. Probably came from a not fully grown animal (or were the individuals not that large in the region ?).
Estimated to have belonged to a 40 footer by Gordon Hubbell and a 12 m by Mike Siversson. Based on tooth width formula, I get too 12,3 m TL for this individual. Allows to have a good insight of the dentition of C. megalodon.





I don't know if that cast also comes from a set of teeth or has been assembled of isolated specimens. As I know, two associated sets have been found in the US and I suspect this one is the other than Hubbell's above. Anyway if true, it may have come from a substantially larger shark. Estimated at 50 feet on boneclones.com. Based on tooth widh formula, I get a 14,1 m megalodon.




The measurements of all teeth in both of these sets are available in that www.boneclones.com/pdf/shark-teeth-sizes.pdf


A full size jaw reproduction made by the Babiarz Institute of Paleontological Studies, the team having made the jaws seen in Nat Geo.
Measures 2,03 m high and 2,56 m wide. Would represent an approaching 60 feet shark.

[elosha11]

Nice finds Grey. I've never seen these before.

[Grey]

For speaking with a fossil sharks teeth collector, this particular specimen is difficult as it would be a 4th or 5th position (the curvature and the left-right length ratio).

If true, this is clearly not the largest tooth in the mandible and the owner could be one gigantic shark.

Shimada's method could give some possible indication there.

The last time he heard of that tooth, it was in a private collection in Switzerland.

Edit : using Shimada, if that tooth is a L1 or L2, I get a range of approx. 17.5-18.5 m TL, conservatively as I've perhaps excluded 5 mm of crown gien the unprecise view of the picture. If so, I get 18.2-19.2 m TL.

Using Jeremiah, I get approx. 18-18.5 m TL. But this is conserative as this is apparently not an UA. Edit : given the possible position of the tooth, it could be the widest tooth of the dentition. In megalodon, the UA are not the widest teeth, they are equalled or exceeded by the 4th or 5th (seen boneclone paper).

This means that the Jeremiah results here are probably close to the truth, but this means also that Jeremiah's method used on UA width normally produces conserative estimates of TL.

In anycase, if it was like extant predatory lamniforms in its morphology, that is one big shark, potentially 17.5-19.2 m TL (and more likely 18-18.5 m TL).

If we follow Gottfried regression, this corresponds to an approaching 70 tonnes megalodon. If we follow a more classical lamnid shape, we get something around 50-60 tonnes (Siversson).

[Grey]

Hm givent that this is not based on the original description... I dont see how this case does not apply exactly. Typically we have some shit on the internet like 20m Megalodon and 500 tonne Broome trackmaker (wish I was kidding). Then it collapses down.

Taken fro CF.

coherentsheaf

Place on the same step 20 m megalodon and 500 tons sauropods is perfectly unfair.

20 m for C. megalodon is not conclusive at this point but not unreasonnable either. You can see throughout the thread that the 20 m mark is several times approached or reached, through the various methods. Several authors acknowledge it for some reason. Based on the jaw perimeter in lamniforms, Mike Siversson suggests C. megalodon approached 20 metres, the largest teeth he worked on resulting in 18-19 m TL.

On the other hand, no sauropod specialist I've read about has ever seriously considered 500 tons sauropods by any mean.

Both figures are absolutely not equivalent in terms of credential.

Look what they did to Megalodon. They thought they were 70 feet. Now it's 40 feet.

DinosaurMichael,

The first estimates for megalodon exceeded 120 feet, not 70 feet.
40 feet was fixed by Randall using enamel height of 11-12 cm upper anterior teeth in the 70's. Today, the sharks specialists community places C. megalodon potential max size at 55-70 feet, 60 feet being close to actual consensus.

@brolyeuphyfusion

There's no 30 m chimera as Parahelicoprion. Stop to engulf every non-sense you get on the internet by any random guy.

[creature386]

Jul 8, 2013 0:43:12 GMT 5 Grey said:

There's no 30 m chimera as Parahelicoprion. Stop to engulf every non-sense you get on the internet by any random guy.

He likely doesn't believe it anymore, theropod already has shown that it is false.

[coherentsheaf]

Jul 8, 2013 0:43:12 GMT 5 Grey said:

Hm givent that this is not based on the original description... I dont see how this case does not apply exactly. Typically we have some shit on the internet like 20m Megalodon and 500 tonne Broome trackmaker (wish I was kidding). Then it collapses down.

Taken fro CF.

coherentsheaf

Place on the same step 20 m megalodon and 500 tons sauropods is perfectly unfair.

20 m for C. megalodon is not conclusive at this point but not unreasonnable either. You can see throughout the thread that the 20 m mark is several times approached or reached, through the various methods. Several authors acknowledge it for some reason. Based on the jaw perimeter in lamniforms, Mike Siversson suggests C. megalodon approached 20 metres, the largest teeth he worked on resulting in 18-19 m TL.

On the other hand, no sauropod specialist I've read about has ever seriously considered 500 tons sauropods by any mean.

Both figures are absolutely not equivalent in terms of credential.

I did not say they were equivalent. I just said that based on the evidence that was avilable at the time of proposal they were both unreasonable... which I believe they were. For the record: I think a 500tonne sauropod is less likely than a 20m shark and indicated as much by setting the "whish I was kidding part" behind it.

[Grey]

Fair enough, I was skeptical of such a thing coming from you !

Yes, creature, I've read that theropod brought some seriousness in that pathetic thread. But Darckgricer has also retracted this.

[Grey]

Particularly large posterior tooth 9.1 cm in slant height and 8.1 cm in width.

Using the associated set of fossil teeth owned by Gordon Hubbell, by calculation I get that the longest upper anterior tooth in the dention in which this posterior belonged measured between 17.2 and 19.6 cm, mean of 18.4 cm, identical to Hubbell's large tooth in slant height, with a width for that same tooth between 12.9 and 13.4 cm. However, the very widest tooth in Hubbell's set (L5) would yeild a width between 14 and 14.5 cm.

Whatever this last estimate can be likely too much, the large tooth owned by Hubbell being 13.7 cm wide, this would suggest that in anycase, this posterior tooth seems to have belonged to a large megalodon, perhaps very large, IMO similar to the owner of the "large Hubbell's tooth" (estimated at 17.5 m TL using Gottfried regression and 18.8 m TL with jaw perimeter's basis). I was unable to use Shimada as I don't know the crown measurements.

Once again, the variation and uncertainties make these figures only potential.