Tyrannosaurus is comfortably the largest when talking about near-complete specimens.
When talking about largest known (or average) specimens, including fragmentary material, the situation becomes a hell of a lot less clear especially when you consider the low sample size of some of the species involved.
The exact ordering will vary depending on who you ask. In my opinion, based on largest known specimen, the top bunch goes something like:
Tyrannosaurus (8,400 kg; Hartman)
Giganotosaurus (~8,200 kg; Hartman)
Mapusaurus (>8,000 kg)
Tyrannotitan (~7,600 kg; femur circumference)
Carcharodontosaurus (~7,200 kg; skull length)
Sauroniops (~7,200 kg; assumed to be same size as
C. saharicus)
Deinocheirus (~7,200 kg; mean of two Campione et al. femur circumference equations)
If MSNM V4047 does indeed turn out to be a
Spinosaurus after all then it might be slightly larger than
Tyrannosaurus. If we just base it on the type specimen instead then it doesn't really make the cut, ending up at roughly the same sort of size as
Acrocanthosaurus.
I have previously made a very rough GDI of
Spinosaurus - I used the chest width I estimated from the ribs and vertebrae figured in Stromer's plates, narrowed Scott Hartman's
Giganotosaurus dorsal view based on this width estimate, modified the proportions of it's body segments to match his
Spinosaurus, then performed a GDI and got an estimate of ~7,200 kg (making it the fourth theropod I estimated at that exact mass... for some reason).
However, that is based on old data now, with a normal-sized pelvic girdle and
Tyrannosaurus-sized hindlimbs. I shrunk down the pelvis and hindlimbs to try and match Ibrahim et al.'s specimen, and re-did the GDI achieving an estimate of ~6,200 kg.
Hartman restores MSNM V4047 as 11.4% bigger than the type specimen, meaning an estimated mass of ~8,600 kg.
I don't consider any of the Jurassic theropods known from actual skeletal remains to be big enough. The largest is, in my opinion,
Epanterias, which I estimate at only ~4,800 kg based on both MOR 693 and DINO 2560.
Of course this is all based on the largest known specimen of each. Average size is a better comparison but we don't really know how big the average specimen of each is. We could try to estimate it though.
The average
Tyrannosaurus femur is something like 121 cm long, suggesting a mass of ~6,600 kg. However, this excludes several quite large and a couple of very small specimens - I have postulated in the past that including these in the sample could suggest an average individual actually had a femur around 127 cm long (~7,600 kg), but that is a rough estimate at best.
The average of the two
Giganotosaurus specimens is ~7,500 kg.
Mapusaurus is known from a bone bed of many specimens, at least one of which is juvenile. The range of adult size is thus near impossible to estimate. Some potential adult specimens probably weighed under 6,000 kg (femur length 130 cm), the very largest may have exceeded 8,000 kg, so perhaps ~7,000 kg can be used as a very, very rough estimate of the average?
The paratype of
Tyrannotitan has a femur 141 cm long, the holotype 127 cm long. The average of these two can thus be estimated at ~6,500 kg.
The holotype of
Carcharodontosaurus is some ~15% smaller than the neotype. The average of these two can thus be estimated at ~6,000 kg.
Only one specimen of
Sauroniops is known, and it is comparable in size to the
Carcharodontosaurus neotype specimen, so ~7,200 kg.
The holotype of
Deinocheirus is ~6% smaller than the largest specimen, the average of these two can thus be estimated at ~6,600 kg. Another much smaller specimen is known, but is probably sub-adult.
As noted above I estimated the holotype of
Spinosaurus at 6,200 kg. If MSNM V4047 truly is a
Spinosaurus then we can average the two specimens out to ~7,400 kg. This means there are bundles of other specimens we could include too, but most of those are probably sub-adult based on them being smaller than the sub-adult Ibrahim et al. specimen.
So I guess based on my estimated average sizes the list would be as follows:
?(
Tyrannosaurus; ~7,600 kg)
Giganotosaurus; ~7,500 kg
?(
Spinosaurus; ~7,400 kg)
Sauroniops; ~7,200 kg
?(
Mapusaurus; ~7,000 kg?)
Tyrannosaurus; ~6,600 kg
Deinocheirus; ~6,600 kg
Tyrannotitan; ~6,500 kg
Spinosaurus; ~6,200 kg
Carcharodontosaurus; ~6,000 kg
I haven't included
Sigilmassasaurus or
Bahariasaurus in this because I don't know how big I think they are but both are known from vertebrae rivalling
Spinosaurus and
Tyrannosaurus in size, so both are clearly enormous.
