Herbivore dinosaurs...

[DinoFan83]

I'd like to make a post about the potential size of the sauropod Notocolossus.

In regards to its mass, Greg Paul (2019), on the basis of the size of its dorsal centrum, estimates it to be comparable in size to Patagotitan at 45-55 tonnes, with the possibility that it may be larger and closer to Argentinosaurus in size at 65-75 tonnes. I'm inclined to agree with this because, as stated in the linked paper, the centrum in the only preserved dorsal vertebra is about the same size as that in Patagotitan/Puertasaurus, yet many titanosaurs have shorter anterior dorsals than posterior so the animal may have been larger than Patagotitan and closer to Argentinosaurus; these sizes are also supported by the size of the humerus (176 cm, Gonzalez-Riga, 2016).

Length can be inferred based on cross scaling its dorsal vertebrae to more complete relatives; as per Carballido et al. 2017, the width of the diapophysis of the second dorsal vertebra of Patagotitan, Notocolossus, and Puertasaurus are 140, 150, and 168 cm, respectively, and the wider a titanosaur's ribcage is, the wider its diapophyses are in order to support that width. Randomdinos restores Puertasaurus at 28.6 meters and 60 tonnes (note that it may very well be up to 35 meters and 100-110 tonnes as per some other reconstructions, but I'll use this one because it has a mass estimation), and Patagotitan at 30 meters and 55 tonnes (Greg Paul restores both animals at approximately these sizes as well). This means Puertasaurus possesses a diapophysis 20% wider than Patagotitan and is thus 25.9% heavier at the same length.
Applying this disparity to the disparity between Patagotitan and Notocolossus dorsal width (150 vs 140 cm) suggests Notocolossus would be slightly over 12.4 percent heavier at length parity (meaning, for example, a 30 meter Notocolossus would be 61.8 tonnes compared to 55 tonnes for a 30 meter Patagotitan). So overall, if we were to use Greg Paul's estimates as the basis for mass, this means that Notocolossus would have been ~27-32 meters long and 45-75 tonnes in weight. 
Interestingly this is almost exactly the same as the 45-76 tonnes the Notocolossus holotype was estimated to weigh via the circumference of its humerus in Gonzalez-Riga et al. 2016. Reply