Giant theropods overview thread

[creature386]

Oct 11, 2015 20:03:30 GMT 5 Infinity Blade said:

Allow me to take a guess; this Frank Fang is yet another of countless Tyrannosaurus fanatics claiming UCMP 137538 to be some hideously huge specimen?

Yup, along with his claims of UCMP 118742's size. He is possibly the greatest authority in the Tyrannosaurus pseudoscience community.
Mathematics Equations used to find UCMP 118742's size.

Dunno if this has been posted here yet, but these equations are usually used by T. rex fanboys in arguments to prove that UCMP 118742 is huge or could grow to an extreme size:

Method 1:
{A/[1
+ exp(-0.57(age-B))]} + 5 = body mass(kg)make B=16, change A until
16year old UCMP 118742's body mass is 20% greater than FNMH P 2081FNMH
PR's body mass is 5600kg(min)--6400kg(lower
limit)--8500kg(conservative)--10000kg(up­per-limit)--11400kg(upper
limit)than replug B=22(average age of Tyrannosauurs rex)
Method 2:
Henderson's equation1.03161 * 10^(0.85673*Log(Skull
Length(cm))+0.93482)= body length1.00419 * 10(3.6022*Log(Skull Length
(cm))+3.4426) = body mass suggested skull length of UCMP 118742 (16year
old) is 1550cmfor adult size, 1620cm.

Equation for body length provided by Frank Fang

Body Length ;= 2.45161*10^(1.4373*LOG(skull length (cm))+0.105+(0.36082*(age(years)*(1.035^­(28-age(years)/28))))
Weight =1.08019 * 10^(3.6322*LOG(body length (meter)/8.63)+3.4426)

[Method 2:]

Maxilla size/body ratio provided by Frank Fang aka Celestial Emperor Fang.

1- AMNH 5027 22 years old, 12.5 meters, skull length 1.36 meters. Based on AMNH 5027, UCMP 118742 would be around 14.19 meters.

2 - Largest skull MOR008 22 years old (maxillary 720mm). Base on that, UCMP 118742 would be 15.4 meters long.

3 - B-rex AKA: MOR1125 18 years old, 10.54 meters (maxillary 680mm). Based on that UCMP 118742 would be 12.5 meters.

4 - Stan (BHI 3033) 18 years old, 12.3 meters (maxillary 775mm). Based on that, UCMP 118742 would be 12.86 meters.

5 - Holotype (CM 9380) 12.04 meters, 22 years old (maxilla 695mm). Based on that number, UCMP 118742 would be 14.45 meters.

6 - Peck's T.rex/Rigby's T.rex MOR 980 21 years old, 12.8 meters (maxilla
770mm). Based on that, UCMP 118742 would be 13.46 meters.

7 - MOR 555 22 years old 12.4 meters (maxilla 798mm). Based on that, UCMP 118742 would be 12.59 meters.

I haven't found the equations for UCMP 137538 yet. They are obviously no simple isometric scaling, as he got above 14.4 m.

Looks like they are because the Illiterate Scholar puts the length of UCMP 137538 at 14.4 m in his summary of Frank Fang's work:
www.topix.com/forum/science/dinosaurs/TBT80UQPE6R27LQ9I

[blaze]

Isn't that guy inactive? I don't remember seeing anything from him more recent than 2011. "Public shaming" seems way overboard, while the fanboy fuel he produced is annoying it is not that big of a deal IRL and I suppose he wasn't very old, I mean, choosing nicknames like Celestial Emperor seems like something someone in middle school would do (thinking of chūnibyō, myself at that age lol).

spinodontosaurus
I think you did the best that can be done with the information we have, the only think left to be entirely sure if the measurements are correct will be to contact Brochu and Longrich.

[creature386]

I know that he is inactive, I was trying to give Macronectes some "history knowledge" because that guy is kinda legendary, so I thought it won't be bad for someone who is into these matters to know him.

Hm, I am not sure if someone who can make such calculations can really be called a middle schooler, but we of course cannot know who is the real head behind them.

[blaze]

Well, he used those from Therrien and Henderson (2007), some isometric scaling and some linear regression equations (very easy to do in Excel even if you don't know/understand the theory behind them), nothing terribly complex.

The latter have some weird additions though, probably attempts at trying to make the equations do what they were not supposed to do, for example, if I put Sue's data in his body length equation it tells me Sue is 26m long, his weight one also gives insane numbers, 29 tonnes for the supposed adult size of the UCMP maxilla (16.2m), 2-3 times higher than isometry. I could be using them wrong but they don't look like actual growth equations anyway.

[Dakotaraptor]

Even 11.6-11.9 m (based on FMNH) would be pretty big, assuming the specimen (UCMP 118742) was only 16 years old. That's comparable in length to Wankel and Holotype, which their age is estimated of 22 (Erickson et. al 2004).

So would full-grown UCMP 118742 be like 12.1-12.4 m? I am not sure.

[theropod]

And we can never be sure. How did it get to 11.8m at 16 years of age? Certainly not by growing at the same pace as the average Tyrannosaurus. There’s just no telling in what way its life history differed, but you don’t automatically have to assume that it would have grown equally much as, or more than every other 16-year old Tyrannosaurus. It may have been that large at that age because it had less left to grow.

we can only speculate what exactly led to this individual variation, but here are some possibilities:

The red line is based on the original model from Erickson et al., but modified so that it provides length estimates based on isometric scaling from sue. The yellow lines are modifications thereof that are multiplied (y*1.231) or shifted (y+222.1239 or x-4.09379) so that they intersect UCMP 118742.

This is also why I think whatever that Frank Fang guy did is utter bullshit, even using the highest of these modifications we don't get much more than 15m, certainly not 16+. That's not even mentioning how stupid and biased it is to "estimate" (or really just let your imagination run wild about) the hypothetical "adult" size of this particular specimen, but no others (look at all the other specimens that are smaller than expected for their age, why don’t those get a mention considering the same method?).
Also it doesn't account for how small the sample size in those T.rex growth studies is, so that simply adding UCMP 118742 to the sample and re-running the analysis might have major impact on what the typical size of a 16 year old is expected to be.

[spinodontosaurus]

How many other 16 year old adults is there? I know of Bucky, which was quite small, but are there any others?

Bucky itself is not the smallest known adult Tyrannosaurus, basing on femur length I count 5 specimens on the Theropod Database that are smaller; MOR 009, DMNH 2827, BHI 6233, MOR 1125 and USNM 6183. MOR 1125 was estimated to be 18 years old, so it is not unheard of for slightly younger specimens to be larger than specimens older than them.

Having the second longest known Tyrannosaurus maxilla would be impressive for any adult specimen though.

[theropod]

None as far as I can tell, Bucky and UCMP 118742 are the only ones I could find in Erickson et al.’s studies. But the growth curve from 2004 only included the former.

[blaze]

^MOR 555? it trades blows in measurements with UCMP 118742. Just like Erickson et al. had age estimates that differ from other publications we shouldn't think that their estimate for UCMP 118742 is set in stone, specially considering what kind of bone was used for said estimate.

[Deleted]

A new spinosaurid paper has come. Sigilmassasaurus is not Spinosaurus aegyptiacus.

[stomatopod]

Link please?
Found it

[blaze]

And the arguments seem very strong too, really makes you think what Ibrahim et al. were doing when making that referral.

[spinodontosaurus]

Also, with the existence of two spinosaurids in the Kem Kem the referral of MSNM V4047 to Spinosaurus is now suspect. Didn't Jaime Headden once propose that it and the S. aegyptiacus type specimen probably represented different taxa based on his observation that the to jaws did not fit together very well?

[stomatopod]

I think there is a pretty good case for Sigilmassasaurus being a different taxon, but I personally doubt that it is a Baryonychine.
I cannot some of their other arguments, for example doubting the association of the material for the Spinosaurus neotype. Seriously, these are bones that articulate with no duplicates! Voicing this before the publication of the monograph that is underway is, one thing, but making subvert accusations is unacceptable.

[blaze]

spinodontosaurus
Yup, he did, was it in 2013? there's also evidence from teeth (mentioned in Evers et al.) and quadrates (mentioned by them too and I shared it here IIRC) for more than an spinosaurid taxon in the Kem Kem.

stomatopod
I didn't get the impression that they advocated for that, they never recovered it as one, the thing is that Ichthyovenator really blurs the line between baryonychinae and spinosaurinae.