Largest sauropods

[Deleted]

Dec 22, 2014 11:29:12 GMT 5 blaze said:

a 35m individual just can't be 75 tonnes

I've always noticed something really fishy about Paul's 70+ tonne mamenchisaurs. I could never reproduce them by scaling from any of the estimates for smaller relatives that I could find online. A ~35-meter long diplodocoid(like Supersaurus) is roughly in the ~30-60 tonne range give or take a few.

I think Mamenchisaurus sinocanadorum is a creature somewhere in the ~50ish tonne range.

[Deleted]

Some news regarding Dreadnoughtus.

A new paper places Dreadnoughtus schrani, Apatosaurus louisae, and Giraffatitan brancai at the same size tier. Specimens are MPM-PV 1156, CM3018, and HMN SII respectively.

Judging by how the models are fleshed I'd say that the maximal models are the best representatives for healthy animals. Dreadnoughtus and Apatosaurus are both estimated at ~43 cubic meters and ~38 tonnes, while Giraffatitan is estimated at ~40.4 cubic meters and ~35 tonnes.

Well if you looked at the exact numbers it has Dreadnoughtus leading very slightly by mass while Apatosaurus leads very slightly by volume, but the difference is so small, keeping in mind the potential error bars, that this miniscule difference can just be completely disregarded.

Seems like to have a mass equivalent to the original estimate, it would have to be quite obese...

[blaze]

The mounted skeletons of Apatosaurus and Giraffatitan seem to have articulation issues that might be inflating and decreesing their masses.

That of Apatosaurus has its shoulder girdle almost a full meter more anterior than how Hartman restores it, the scapulacorocoid is too horizontal increasing the length of the torso by 3 vertebral positions, the ribs are also not properly swep back, here you can see the issues. and Giraffatitan has a ribcage less wide than the hips.

I do not agree than the maximal models are representatives of a healthy adult, in the only images we have to gauge this, those of Dreadnougthus, the flesh goes 70cm below the level of the pubis and is also 70cm above the neural spines, likewise is also 70cm thick on each side of the ribcage, giving it a torso 4.2m wide.

I think something closer to the standard +21% estimates are more accurate, I do believe Giraffatitan to be about 30 tonnes or a bit more and that'll probably be the case if the mounted skeleton wasn't reconstructed with such a narrow torso.

[Deleted]

Jun 11, 2015 12:14:02 GMT 5 blaze said:

The mounted skeletons of Apatosaurus and Giraffatitan seem to have articulation issues that might be inflating and decreesing their masses.

That of Apatosaurus has its shoulder girdle almost a full meter more anterior than how Hartman restores it and Giraffatitan has a ribcage less wide than the hips.

I do not agree than the maximal models are representatives of a healthy adult, in the only images we have to gauge this, those of Dreadnougthus, the flesh goes 70cm below the level of the pubis and is also 70cm above the neural spines, likewise is also 70cm thick on each side of the ribcage, giving it a torso 4.2m wide.

I think something closer to the standard +21% estimates are more accurate, I do believe Giraffatitan to be about 30 tonnes or a bit more and that'll probably be the case if the mounted skeleton wasn't reconstructed with such a narrow torso.

The extra flesh you mention could easily be more than compensated for by those emaciated tail and neck bases(in dorsal view). The transition between the torso and the tail/neck would have been smoother in the living animal.



I'll try to compare their Apatosaurus with Scott Hartman's later.

EDIT: Scott Hartman's Apatosaurus has a torso ~76.43% of the length and the same back-pubis depth(not full torso depth, it's not comparable seeing as shartman's skeletal isn't shrinkwrapped while the convex hull model is) as that of the convex hull Apatosaurus model. If we use Greg Paul's Apatosaurus skeletal as a guide for the dorsal view, scaling it's neck, tail, and torso sections to match Scott Hartman's reconstruction gives us a rib cage width about ~104.1% of the convex hulled model.



The result would be a torso ~79.56% as voluminous as the convex hull model given the same degree of fleshing. This puts a corrected version of the torso of the convex hull model at ~16 cubic meters. This chops down the volume of the convex hull model to ~22.51 cubic meters, or to a volume ~84.53% of the original version. The respiratory structures in the trunk will also have to be adjusted by the same factor as the trunk itself, bringing down the total volume of the trunk respiratory structures from 290 liters to ~230.7 liters.

Reducing the volume of the +21% model to 84.53% yields ~27.269 cubic meters, and for the maximal model this would be ~36.42 cubic meters. This would result in masses of ~23.13 tonnes(+21% model) and ~32.28 tonnes(maximal model).

As for Giraffatitan, Asier Larramendi made a triple-view skeletal and came up with ~37 cubic meters and ~33 tonnes.

[blaze]

The maximum model adds 10.5 cubic meters of extra flesh over the 21% model that's over 3 times the total volume of the minimum neck and 10 times the minimum of the tail, thicker tail and neck bases are not going to do away with extra 10 tonnes of flesh.

[blaze]

Sept 7, 2014 22:22:03 GMT 5 blaze said:

The 50 tonnes plus for Futalongkosaurus is from Greg Paul, he recently posted in the dml about the weight of Dreadnoughtus and it seems he is oversizing it (Futa) big time, he thinks it's similarly sized to Argentiosaurus and gives it a 2.4m long femur, he also talks about 2.5m brachiosaur femora and then gives his usual estimates for G. brancai and B. altithorax which none of them have femora much longer than 2m.

I just measured his Futa skeletal in page 49 of his recent book, it's 16m from the first cervical to the last sacral, I wonder if he hasn't read Calvo et al. (2008), the conference abstract that says this measurement in Futa is 13m. Nima Sassani also doesn't seem to acknowledge it thus his Futa is also oversized (14.3m C1-S5).

I found said abstract again, it turns out 13m is including the skull (estimated), the actual C1-S6 length is 11.9m, thus Paul's reconstruction is actually ~34% too big and likewise Sassani's turns out to be 20% too big, fix the scaling and the masses they estimate go down to 21t(!) and 29t*.


*Sassani was compelled to make a GDI of his reconstruction after I did one and came out at 45t (density of 0.8kg/l), much lower than his estimate of 70t, his new estimate is 50t.

[Infinity Blade]

So, I've been meaning to ask, what's the consensus (at least currently) on which taxa were the largest sauropods and exactly how large were they?

[blaze]

While reading an article from Nature's open access journal, Scientific reports, I came across this interesting tidbit.


Clicking on it ends up in s 404 page and searching in google gives no results whatsoever for an article with that name so it seems it's still not officially out.

[Deleted]

Nov 22, 2015 5:18:25 GMT 5 Infinity Blade said:

So, I've been meaning to ask, what's the consensus (at least currently) on which taxa were the largest sauropods and exactly how large were they?

There's not really a consensus for both.

[spinodontosaurus]

The paper mentioned by Blaze above is out "A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot" - Notocolossus gonzalezparejasi.

[creature386]

I suck at measuring, but I'd still like to ask a question:

I measured a length of ~520 px* (which could maybe yield an axial length of ~550 px or so) for the dino and 27 px for the scale bar. That'd yield about 20 m in length for the dino, but isn't that a bit very short of a 40-60 t animal?

*Not in this picture (I don't know how it became that small; I have a scale bar vs dino length of 16 px vs ~300 px in case anyone is interested).

[stomatopod]

Not a single word on Antarctosaurus giganteus. huh.

Edit: OK, its in the sup. info.
So it is quite possible that they are the same.

[spinodontosaurus]

Note that the equation that yielded 60 tonnes also yielded about the same for Dreadnoughtus, and 96 tonnes for the isolated femur referred to Argentinosaurus.

Volumetric estimates place Dreadnoughtus in the region of 30-40 tonnes, so I suspect Notocolossus was in that region too. Table 1 compares the dimensions of the humerus to those of other large titanosaurs, Notocolossus' is the longest in the table, but is not much longer than Dreadnoughtus' (176 vs. 160 cm), is narrower at midshaft (25 vs. 32 cm) and at the proximal end (72 vs. 74 cm). Futalognkosaurus' midshaft width is actually the same as Notocolossus', but is narrower proximally and also shorter. The 2nd dorsal is also a bit smaller than Puertasaurus' (150 vs. 168 cm wide).

[creature386]

I did read the part of the paper where this was discussed (hence I included the 40 t). It's just, my measurement is still very small for such a supposedly large sauropod. Is ~20 m even accurate?

[blaze]

creature386
I measured its axial length at 24.4m, head-body length at 13m.

Edit: assuming the torso is relatively accurate, the dimensions of the skeletal seem rather conservative, as the neck was reconstructed at 1.35 times the torso length, based off of Scott Hartman skeletal of Futalognkosarus, it might as well be 1.9 times the torso length so they have comparable head-body length only because despite the Notocolossus reconstruction having a shorter neck it also has a longer torso by 1.1m (27% larger), the scapula (the whole shoulder girdle in fact) also seem rather small for the length of the humerus, it's only 158cm long, using the data from Lacovara et al. (2014) I estimate an scapula 189cm long with +/- error of 12% so between 167cm to 212cm.

If that torso length is accurate, 60 tonnes for it might not be that far off, remember that that same equation gives 38 tonnes to Futalognkosaurus which is not that unreasonable and Notocolossus appears to have similarly "slender" limbs too.


As for the length, keeping the previous assumption and giving it a neck as proportionally long as in Futalognkosaurus it could be reconstructed with a head-body length of 16m, up to 32m long if the tail was 50% of total length, 28m if it was 42% as how Hartman reconstructs Futalognkosaurus.