Megalodon size

[Grey]

Several lateral, posterior or lower teeth which comparatively with the measurements in boneclones, very likely belonged to large/very large megs individuals that probably had 7 inchers upper anterior teeth (diagonal length).



That one is fairly known but that's for suggesting its likely position in the dentition. The width of that specimen is 130 mm.
By comparison, the corresponding L3 or L4 in the Yorktown (adult) and Bone Valley (juvenile) complete dentitions are respectively 90-99 mm (L3), 81-88 mm (L4) and 82-83 mm (L3), 75 mm (L4).




That 65 mm wide chilean is probably a UL8 or UL9.
In the Yorktown adult dentition, the L8 are 50 mm wide, the L9 are 47-48 mm wide.
In the Bone Valley juvenile dentition, the L8 are 35-36 mm wide, the L9 are 27 mm wide.

While a size estimate cannot certainly be based on that posterior because of the vast variations in these teeth, this 65 mm chilean likely comes from a very large dentition that possibly had 7 inchers or so anterior teeth.



That UL5 is 10.79 mm wide.
By comparison, the UL5 in the Yorktown adult meg dentition are 82-83 mm wide.
In the Bone Valley juvenile, 63-65 mm wide.

That one comes most likely from a massive dentition, so probably from a massive shark. No wonder, that tooth is from South Carolina.



A South Carolina Lower Lateral 1 or 2, 11.2 cm wide.

In the Yorktown adult dentition, the corresponding teeth are (L1)80-82 mm, (L2)75-77 mm.
In the Bone Valley juvenile, respectively 65-67 mm and 67-69 mm.



These teeth do suggest that you don't need 6-7 inches teeth (even the first famous Chilean is not really a 7 incher) to have hints of very large Otodus megalodon individuals.

Unsurprisingly, these teeth are from South Carolina, the places where the majority largest megalodon upper anterior teeth specimens found are found.

[Grey]

Mean jaw perimeter in a 5.5 m GWS, the size of the individual from boneclones.

[theropod]

I just went through Mollet’s list again, originally I wanted to ask whether the relatively small ~1m jaw perimeter reported for one individual at 5.5m corresponded to this individual, but I found something different:

To quote Mollet:

Largest white shark caught off California.
Measured length was 18 feet 1/2 inch (5.50 m). Thanks to Mike Shaw, SeaWorld (pers.comm.) Taxidermied specimen was on display at SeaWorld and jaw was later acquired by Gordon Hubbell. Total weight 4,150lbs (1514 kg) (page58 "The Sea World Book Of Sharks" by Eve Bunting). Liver mass 272 kg (600 lbs, 14.46 %); heart mass 4.5 kg (10 lbs, 0.24 %); girth 3.1 m (10' 2", 56% of TL). Shark was harpooned by fisherman Weeren near West end of Catalina Island on June 13, 1976 (14.8 km from shore of Catalina Island, 27.8 km from California coast). Accoroding to Le Boeuf et al. (1982) the stomach contents were nearly digested and could not be identified. The bulk of the material suggested a large animal, probably a marine mammal. Klimley (1985, Fig. 7) reported that the stomach contents of this fish were identified as elephant seal (Mirounge angustirostris) and that the estimated mass was 680 kg. However, these data apply to a different white shark caught on 7 Sep 1975 with TL ~5 m, namely #6 in Table 1 in Le Boeuf et al (1982) for which the stomach content were identified as elephant seal and it was estimated that the elephant seal probably measured 3 m TL and weighed 450 to 680 kg. Thanks to Andrew Sprott who later located an UPI photo with caption in the Fresno Bee dated 17 June, 1976.
From Bone Clone Website:
"The original jaw was prepared by Dr. Gordon Hubbell, a leading researcher in sharks. The original specimen was brought to Sea World in San Diego and was caught off the Southern California coast. The jaw contains a total of 230 teeth (5 rows of 46)." TL is reported to be 19' 6" (5.94 m) which is a likely overestimate.
According to Ralph Collier (email to Andrew Sprott) this shark was measured by Shelly Applegate and Ralph to be TL = 19' 3.5" (5.88 m) and mass 4,680lbs (2123 kg). These appear to be overestimates also.

The linked website however is this→, which is actually a different individual: www.boneclones.com/BC-095.htm

The tooth set with the 747mm width is this→, KO-009, not BC-095. One is a complete jaw, the one I’ve posted previously, the other one is just a dentition.

[Grey]

That's a replicate dentition from the same jaws, both pages have the same indication : "Bone Clones has created a pdf file that contains sizes of all 46 teeth of our great white shark, and both megalodon teeth. Download File"

[theropod]

The expected toothrow lenght for a 5.5m great white shark using Lowry et al. 2009’s regression is ~926mm:
10^(LOG(5500)*1.007-0.8)

Here are the figures in 0.5m intervals up to 20m TL:

TL      Toothrow lenght
5500 925.9
6000 1010.6
6500 1095.5
7000 1180.4
7500 1265.3
8000 1350.2
8500 1435.2
9000 1520.3
9500 1605.3
10000 1690.4
10500 1775.6
11000 1860.7
11500 1945.9
12000 2031.1
12500 2116.4
13000 2201.6
13500 2286.9
14000 2372.2
14500 2457.5
15000 2542.9
15500 2628.2
16000 2713.6
16500 2799
17000 2884.4
17500 2969.9
18000 3055.3
18500 3140.8
19000 3226.3
19500 3311.8
20000 3397.3


The likely dentition lenghts for the individuals thet could be 5.5m long from Mollet’s data→ (based on the assumption that jaw perimeter equals ~117% the dentition length) are the following:

Jaw perimeter	Toothrow lenght
98cm	838mm
112cm	957mm
120cm	1026mm
127cm	1085mm

(Measurements rounded to the nearest centimetre)
The mean perimeter is 114cm and the mean dentition lenght 974mm, so fairly similar to the values you get from the other data posted above. However I strongly presume that a total tooth width of 747mm in a 5.5m shark would be unusual and most likely correspond to the smallest of these, since that is the most parsimonous.

Finding average jaw perimeters and toothrow lenghts is not the difficulty. But we are in need of a specimen of which we know the toothrow lenght AND the tooth measurements.

[theropod]

Apr 1, 2014 22:05:04 GMT 5 Grey said:

That's a replicate dentition from the same jaws, both pages have the same indication : "Bone Clones has created a pdf file that contains sizes of all 46 teeth of our great white shark, and both megalodon teeth. Download File"

But it lists different sizes:

Carcharodon carcharias BC-095 30" High, 36" Wide, 12" Deep, 21" Jaw Opening $2,590.00

for KO-009

The jaw is approximately 35 inches across and 29 inches high

How do we know they are the same size? Perhaps one was cast at a smaller scale, or belongs to different specimen. The small photo of the jaw included in the

[Grey]

That is good finding as I've found something very similar dedued from the graph and the summed tooth width from boneclones. Like I said you privately, temporary that's good for me, but finding a more precise specimen toothrowh and tooth measurements is still needed for sure.

[Grey]

Apr 1, 2014 22:26:19 GMT 5 theropod said:

Apr 1, 2014 22:05:04 GMT 5 Grey said:

That's a replicate dentition from the same jaws, both pages have the same indication : "Bone Clones has created a pdf file that contains sizes of all 46 teeth of our great white shark, and both megalodon teeth. Download File"

But it lists different sizes:

Carcharodon carcharias BC-095 30" High, 36" Wide, 12" Deep, 21" Jaw Opening $2,590.00

for KO-009

The jaw is approximately 35 inches across and 29 inches high

How do we know they are the same size?

That's from the same shark, look at the size and description : www.boneclones.com/images/ko-009-lg.jpg www.boneclones.com/BC-095.htm

There's perhaps an error in the measurements of the original jaws and the replicate dentition.

[theropod]

Well, with all that I think there is no strong basis to doubt what scientists wrote on that matter.

[Grey]

No one is doubting what scientists wrote on that, we are all aware of the chronical issues with the extrapolation. But the data in hand is enough for me to get what I wanted to know originally.

[theropod]

What was that?

[Grey]

How Siversson made his estimate and the approx. spacing, awaiting another data.

[theropod]

I’ve just remeasured the jaw photograph more elaborately and got a 14.4%. That’s reasonably close to the (98/1.17)/74.7-1=12% that we get with the smallest jaw perimeter, considering the tooth-free gape certainly varies by a few percent depending on the idividual.

Interestingly, this corresponds well to what you get using the regression for Carcharhinus leucas, without spacing.

[Grey]

You know how I consider unreliable these measurements but whatever, I'm fine with the deductions I had.

To recall,

Summed upper tooth width from the 5.5 m GW : 747 mm
Bone Valley Juvenile Meg : 1598 mm
Yorktown Adult Meg : 1974 mm

Hubbell's tooth posssessor deduced : ~2913-2926 mm

[theropod]

Those above figures are the only ones we have for that specimen, given it is the same of course.

So, you are back on to direct sizing now?