Herbivore dinosaurs...

[DinoFan83]

Was able to get my hands on an abstract from the new paper about the giant sauropod. Size estimates can now be made because measurements have been given.

Quote:As MOZ-Pv 1221 lacks humerus and femur, estimates of its body mass cannot be estimated using the current main methods (e.g., Campione and Evans, 2012, 2020; Benson et al., 2014; Bates et al., 2016; Campione, 2017; Otero et al. 2019), precluding direct body mass comparisons with other gigantic titanosaurs for which estimates have been made, both by volumetric and scaling methods, such as Dreadnoughtus and Patagotitan (Benson et al., 2014; Bates et al., 2015; Carballido et al., 2017; Campione and Evans, 2020). In comparison to giant titanosaurs, however, the recovered appendicular bones of MOZ-Pv 1221 are larger than any known titanosaur described to date. The maximum dorsoventral height at the proximal section of the scapula (130 cm) is 17% higher than in Patagotitan (Otero et al., 2020), 26% higher than in Dreadnoughtus (Ullmann and Lacovara, 2016), 130% higher than in Mendozasaurus (González Riga et al., 2018), and 94% higher than in Drusilasaura (Navarrete et al., 2011). The maximum proximodistal length of the pubis of MOZ-Pv 1221 is 166 cm, which is 10% longer than in Patagotitan, 18% longer than in Dreadnoughtus, and 21% longer than in Futalognkosaurus. At present there is no reliable information for comparison with other giants such as Puertasaurus and Argentinosaurus. So although it is not currently possible to estimate the body mass of MOZ-Pv 1221 (limb bones having been found but not excavated), it is clear that the titanosaur partially recovered from the Candeleros Formation can be considered one of the largest titanosaurs, probably of a body mass comparable to Patagotitan or Argentinosaurus or even larger.

The best species used in these comparisons for size estimations are probably Patagotitan, Dreadnoughtus, and Futalognkosaurus, due to their completeness. Estimates will be listed in order of comparisons with said species in the above quote.

Was MOZ-Pv 1221 really that much bigger than Patagotitan?

Scapula 17% taller dorsoventrally? Check.
As per Page 8 and Table 2 of Otero et al. (2020), that measurement in the Patagotitan holotype is 111 cm.

Pubis 10% longer proximodistally? Check.
Table 2 of Otero et al. gives the length of the pubis of the Patagotitan holotype as 150 cm.

How big was Patagotitan?

As per Larramendi & Paul (2020), sauropods have a higher specific gravity than previously thought.
The mean of it would have been 95% as dense as water, as opposed to the 80% as dense as water that Wedel et al. (2005) estimated and that subsequent studies (such as Bates et al. (2016)) have roughly adhered to.

Quote:The resulting NSG values in analyzed sauropods range from 0.917 to 0.984. These are significantly higher than estimated by Bates et al. (2016) which included most of the sauropod genera calculated here. They found very low SGs ranging from 0.776 to 0.929 –excluding their minimum convex hull models which further reduce the SGs–. Their low results are because the authors applied an overly low SG of just 1.0 to different apneumatic sections, and estimated extremely large respiratory systems for most of the sample which generally far exceed even what is expected in flying birds in a neutral state. Because the poorly pneumatized vertebrae of dicraeosaurids, the species in this clade were found to be the densest (Table 10), while the lowest NSG were found in the sauropods with the longest necks like mamenchisaurids, Giraffatitan, Barosaurus and Euhelopus with a NSG approaching to 0.93 in some cases. Colossal sized titanosaur carrying relatively large necks (Paul, 2019), were probably in this region (Table 10), or slightly below because their very wide torsos may have allowed them to possess relatively larger respiratory systems. If the lesser density of the neck of the neck relative to the rest of the body is not taken into account when calculating total BM, the later will be overestimated by up to ~3% among very large necked sauropods such as mamenchisaurs and brachiosaurs relative to short necked examples such as shunosaurs. The BM results herein are ~5-12% higher than for the same specimens volumetrically massed by Paul (2016, 2019) for the same specimens due to the lower NSGs used in those efforts. 

Applying this mean to the older, low-density estimates (such as randomdinos' 55000 kg estimate) gives us an estimate of 65300 kg for the weight of the Patagotitan holotype, and SpinoInWonderland estimates it at 30.8 meters long.

How big was MOZ-Pv 1221 based on these estimates for Patagotitan?

Scapula based estimate:

Given the respective dorsoventral scapula heights of 130 and 111 cm for MOZ-Pv 1221 and Patagotitan, we can estimate MOZ-Pv 1221 at 36.1 meters in length and 104900 kg in weight based on the above.

Pubis based estimate:

Given the respective proximodistal pubis lengths of 166 and 150 cm for MOZ-Pv 1221 and Patagotitan, we can estimate MOZ-Pv 1221 at 34.1 meters in length and 88500 kg in weight based on the above.

Mean Patagotitan-based size estimate for MOZ-Pv 1221 is 35.1 meters and 96700 kg.

Was MOZ-Pv 1221 really that much bigger than Dreadnoughtus?

Scapula 26% taller dorsoventrally? Nope, it's even bigger than that.
I don't know where in Ullmann & Lacovara (2016) they got that from, as there is no measurement given for the dorsoventral height of the scapula and that measurement appears to be 99.2 cm based on Figure 2 of Page 5 as well as their given 174 cm measurement for the whole thing, meaning the scapula of MOZ-Pv 1221 is actually 31% taller than that of the Dreadnoughtus holotype.

Pubis 18% longer proximodistally? Nope again, it is bigger than that too.
Lacovara et al. (2014) gives the proximodistal pubis length of the Dreadnoughtus holotype at 126 cm with the other linked paper on the animal giving nothing contradicting this, so I don't know where Otero et al. (2021) got that MOZ-Pv 1221's pubis was only 18% longer proximodistally than that of the Dreadnoughtus holotype given that everything published suggests it's about 31.7% larger (which is also consistent with the scapula size disparity). 

How big was Dreadnoughtus?

Matt Wedel has done a volumetric model of the Dreadnoughtus holotype and got a total of 51 cubic meters, but the 32-cubic meter torso is probably some 15-20% too long and chopping the mean (17.5%) of this off it gives us slightly over 46.2 cubic meters for the corrected model.
Based on the new mean density from Larramendi et al. outlined above, we can estimate its mass at 44000 kg, and SpinoInWonderland estimates its length at 27.6 meters. 

How big was MOZ-Pv 1221 based on these estimates for Dreadnoughtus?

Scapula based estimate: 

Given the respective dorsoventral scapula heights of 130 and 99.2 cm for MOZ-Pv 1221 and the Dreadnoughtus holotype, we can estimate MOZ-Pv 1221 at 36.2 meters in length and 99000 kg in weight based on the above.

Pubis based estimate:

Given the respective proximodistal pubis lengths of 166 and 126 cm for MOZ-Pv 1221 and the Dreadnoughtus holotype, we can estimate MOZ-Pv 1221 at 36.4 meters in length and 100600 kg in weight based on the above. That this estimate ended up so close to the scapula-based estimate is certainly pleasing.

Mean Dreadnoughtus-based size estimate for MOZ-Pv 1221 is 36.3 meters and 99800 kg.

Was MOZ-Pv 1221 really that much larger than Futalognkosaurus?

Scapula dorsoventral height (bonus)? Nope, the disparity between the dorsoventral scapula heights is the greatest discrepancy of overlapping elements in both.
Paleo King's Futalognkosaurus skeletal shows the maximum dorsoventral scapula height of the holotype as 99.1 cm given the scalebar (for those wondering why there was no comparison of scapular height with MOZ-Pv 1221 made in the paper, he used unpublished material), and we therefore get a size difference of more than 31.1% between the scapulae of the Futalognkosaurus holotype and MOZ-Pv 1221, greater than the difference between the proximodistal pubis length of those specimens.

Pubis 21% longer proximodistally? Check.
Page 4 of Calvo et al. (2007) gives the proximodistal length of the pubis of the Futalognkosaurus holotype as 137 cm.

How big was Futalognkosaurus?

Benson et al. (2014) estimates the mass of the holotype specimen at 38100 kg, and SpinoInWonderland estimates its length at 23.6 meters.

How big was MOZ-Pv 1221 based on these estimates for Futalognkosaurus?

Scapula based estimate:

Given the respective dorsoventral scapula heights of 130 and 99.1 cm for MOZ-Pv 1221 and the Futalognkosaurus holotype, we can estimate MOZ-Pv 1221 at 31 meters in length and 86000 kg in weight based on the above.

Pubis based estimate:

Given the respective proximodistal pubis lengths of 166 and 137 cm for MOZ-Pv 1221 and the Futalognkosaurus holotype, we can estimate MOZ-Pv 1221 at 28.6 meters in length and 67800 kg in weight based on the above.

Mean Futalognkosaurus-based size estimate for MOZ-Pv 1221 is 29.8 meters and 76900 kg.

If these size estimates are accurate, I could not agree more with this statement from the paper, especially the bolded and underlined part:

Quote:It is clear that the titanosaur partially recovered from the Candeleros Formation can be considered one of the largest titanosaurs, probably of a body mass comparable to Patagotitan or Argentinosaurus or even larger.

Reply