Oxalaia vs Tarbosaurus

He is actually right about your statement being irrelevant, as it does not prove your point in this thread.

5 tons sounds like an exaggeration for Oxalaia quilombensis if we take the ~16m, ~11.5t guesstimate for Spinosaurus aegyptiacus and scale it down. The result would be ~4.8 tons, but it's worth nothing that scaling in nature is allometric, not isometric.

You would likely get errors if you scaled isometrically as well, seeing as scaling in real life is not isometric, and one of the most common estimates actually assumes isometry, and even then we'd have to be careful with our estimates since both Spinosaurus aegyptiacus and Oxalaia quilombensis are rather fragmentary (unless it turns out Sereno found more remains than we expected).

Of course, the point is to minimize the margin of error.
If you first isometrically scale up and the allometrically scale down, you are summing up errors by first making an estimate for a larger animal based on one method, then scaling down from that estimate using another.
You’ll end up assuming Spinosaurus was proportioned like its smaller relatives even though allometric trends would indicate it to be bulkier, and then scaling down from that to come up with an estimate for an animal intermediate between these that will then be assumed to be less bulky than either.

If you want to use an allometric method you have to do that from the beginning, i.e. scale up allometrically from animals whose weights are known, not from animals whose weights base on isometric scaling. But I find that a big pointless since we don’t have any data on allomatric trends within spinosauridae, and are not very likely to get them in the near future.

Yeah, but in what direction?

Oxalalia wins