Futalognkosaurus ontogenetic stage

[dinosauria101]

So, apparently, the holotype of Futalognkosaurus (even though it's already 38-70 tonnes) might be a subadult as some limb bones that may have come from the holotype and are a good fit for it based on size are from a subadult (the supplementary material of Benson 2014 cites this (DE direct measurements of limb bones-femoral circumference slightly approximated; Calvo et al. 2007a,b; MUCPv-323, vertebrae and pelvis), which states they're from a subadult, and Benson 2014 lists them as part of the holotype).
How plausible might this be? Discuss

[Ceratodromeus]

"subadult" is such an oversaturated term in paleontology.

Given the fact that Calvo never mentioned any features suggesting immaturity in his paper on the morphology of Futalognkosaurus, and the fact you can't rule out the presence of neoteny, i would really be hesitant to claim that this was an "immature" animal.

[dinosauria101]

Yeah, neoteny is always difficult in palaeontology. Very hard to tell which animals have it and which do not.

That being said, the reason why Calvo never mentioned those limb bones is because they apparently weren't described or figured appropriately. This is where I heard it; maybe there's a bit more info on DA: www.deviantart.com/palaeozoologist/art/Futalognkosaurus-skeletal-183472189?comment=1%3A183472189%3A3606823854
(they may not be part of the holotype however, just a similar size animal that was not grown as blaze says).