MMIII "fleshraker dinosaur" has a tail attack and is described as a dromaeosaur-type (but then, it also has poison)
Also, in 4th ed, the T. rex analog- fang titan drake in 4E MM2- has a tail attack.
Well I'd consider both of those Fantasy Dinosaurs so they aren't really relevant. Now I quite like fantasy versions of theropod dinosaurs, but they're not really germane to this thread.
The reason I prefer long reach Huge- is that there is precedent (MM2 Allosaurus- 3.5 updated version)
I have a couple of problems with that approach. Firstly, it's a holdover from the 3.0 edition of D&D. In the original 3rd edition Monster Manual both
Tyrannosaurus and
Megaraptor were Huge Tall creatures too (10 [FONT="]×[/FONT]10 space, 15 foot reach). When they updated to 3.5 they changed them both to short-reach creatures, and dropped Megaraptor down to Large.
Making
Tyrannosaurus or
Allosaurus the same space/reach as a 16-32 foot tall giant doesn't jibe very well with me, at least for a version based on more modern reconstructions (I have no objection to a 3.0 edition Tall
Tyrannosaurus as a towering tail-dragger straight out of a pulp novel or b&w film).
If the
Tyrannosaurus and
Allosaurus were Huge Long creature (10 [FONT="]×[/FONT]20 space, 10 foot reach) under 3.0 rules they would work out about 40 feet long under the Space plus twice Reach rule-of-thumb (20+10+10), which seems a perfectly good fit.
and that Short Reach Gargantuan (20 ft space, 15 ft reach), seems a bit on the large side- basically- it assumes the creature is around 50 ft long.
Spinosaurus is Long Reach Gargantuan (20 ft space, 20 ft reach) in the 3.5 update to MM2.
This works well for a 60 ft creature (the upper limit of length estimates)
But doing all the big theropods as Long reach Huge (15 ft space, 15 ft reach- at least with bite) seems to work well with the 45 ft length of most of the biggest theropods.
Plus- weight is a bit of a deciding factor- a 6.5 ton dinosaur just is a bit underweight for gargantuan.
At least for me.
Yes, well I tend to consider those weight limits more are guidelines. There are a fair few creatures that break them. For example, the SRD lion is Large sized and listed as weighing 330-550 pounds for the larger males. If, say, an average lion weighs 350 pounds that's 70% of the minimum standard weight limit of a Large creature. A Gargantuan beast with the same 70% mass would be 22400 pounds, which is pretty much spot on the upper weight estimates for the largest theropods - except for
Spinosaurus aegypticus, of course.
I imagine Theropod dinosaurs were pretty lightweight but extremely strong, they did have weight saving adaptations involving air-sacs and hollowed bones after all, so I consider a Gargantuan short-reached
Tyrannosaurus quite acceptable. Besides, the 3.5 edition SRD
Tyrannosaurus advances to Gargantuan size, and I didn't want to change it. Although I draw the line at the 3.0 and d20 Modern version which advances to Colossal, that's as crazy as the SRD tiger growing to Huge size!
Besides, I'm happy to allow for a 50 foot long carnosaur. Even if we don't have any reliable fossil evidence they grew that big, it's not that much longer than the largest known non-Spinosaur, and I consider a bit of exaggeration quite forgivable in a fantasy RPG like D&D.
And remember, I'm not arguing that all of the "supersize" carnosaurs should be Gargantuan, only exceptionally big outliers. E.g. the vast majority of adult
Giganotosaurus would be Huge, but very rare individuals have advanced enough extra Hit Dice to become Gargantuan.
My preferred Hit Dice number for T. rex is 20- it has a lot of precedent- the D&D Expert Handbook version has 20 Hit Dice, the D20 modern version has 20 Hit Dice, and I'm betting the AD&D 2nd ed version had 20 Hit Dice as well- it has legacy value.
Afraid not, the D&D Tyrannosaurus had 18 Hit Dice in both 1st and 2nd edition AD&D, so if anything the D&D SRD's 18 HD has 'Legacy Value'.
To fill out the size list:
Medium- up to 15 ft long
Large (5 ft reach) around 20 ft long
Large (10 ft reach) around 30 ft long
Huge (10 ft reach) around 35 ft long
Huge (15 ft reach) around 45 ft long
Gargantuan (15 ft reach) around 50 ft long
Gargantuan (20 ft reach) around 60 ft long
I still don't care for switching between long and short reach for different sized animals.
Firstly, they're build in the same proportions, so I'd prefer them to have the same reach.
Secondly, it raises a problem with Advancement, especially with theropods that have a wide range of sizes. Wouldn't you'd be having thing like Advancement: 7-10 HD (Large short); 8-14 (Large long); 15-12 (Huge short)?
That just seems cumbersome to me.
For an example of a creature that would fit into Gargantuan Short Reach far better than T. rex- Shantungosaurus or Lambeosaurus laticaudus: both are in the 50 ft long- 16 odd tons in weight- so I think they are much better candidates.
Yes, the largest hadrosaur species would certainly be Gargantuan in 3E D&D terms as "average adults". That's not really what I'm shooting for with theropods, were I fancy having particularly big specimens reaching that size after a lot of HD Advancement.