Ok, i remember reading on the list a while ago three particular complaints about the Spinosaurus in JP3...
I haven't seen the movie yet (will see it tomorrow), but i was just going through my photographs of _Baryonyx walkeri_ at the BMNH and _Suchomimus tenerensis_ in Chicago, and the drawings of _Spinosaurus aegypticus_ material in "The Dinosauria", and memories of the complaints about the movie occured to me.
*I beleive one complaint about the JP3 animal was the lack of a particularly large claw of the kind in _Baryonyx_... couldn't miss this feature in the _Baryonyx_ display, but _Suchomimus_ doesn't *appear* to have it - at least not to _Baryonyx_'s extent, or an extent that i *imagine* would be too noticeable on _Spinosaurus_ in the movie.
(Side note: I recall something about _Baryonyx_ having serrations on the teeth that _Spinosaurus_ did not... could this mean _Baryonyx_ was slightly more specialized for piscivory (the serrations helping to grab onto slippery fish?), i mean, one step up from having the crocodile-like jaws? The big ungual has also been suggested as a fish-catching adaptation... if _Spinosaurus_ actually does lack one of _Baryonyx_'s possibly-more-derived(this is all guesswork... i dont know if it's actually considered more or less derived compared to _Spinosaurus_) piscivory adaptations, then why not another? Now i'm sure this wasn't the Hollywood people's rationale, but still, a valid potential excuse, i think.)
*Then there was the teeth - apparently in the film Grant picks up a curved tooth and says "Spinosaurus!" or something like that, but the tooth he picks up is curved rather than straight (like the _Spinosaurus_ tooth drawing) - i guess i don't need to point out to anyone that the skeletons that both _Suchomimus_ and _Baryonyx_ have teeth that look a lot more like the kind of thing Hollywood would call a "big scary dinosaur tooth" (i.e. much more curved).
*The third complaint i recall was that the JP3 animal appeared to have lacrimal horns... well i don't know if it involves the "lacrimal" (it does actually seem to, from an uneducated perspective), but _Suchomimus tenerensis_ really does seem to have little protuberances of a vaguely similar (maybe not as big) shape to _Allosaurus_ above the orbits. And really, the shots of the _Spinosaurus_'s head that i've seen in the previews do seem roughly faithful to _Suchomimus_'s skull profile: as far as it's "lacrimal"-ish nobbly bits go, i mean.
So yeah, i say again that i havent seen it yet (i didnt want to wait till tomorrow to post it because i knew id forget... but i suppose those of you sick of JP3 conversation would've thought that a good thing!), but it seems to me like the filmakers based the JP3 _Spinosaurus_ on _Suchomimus_... which would make sense, since it is _Suchomimus_ that's gotten the biggest and most recent bit of press out of the two animals, and alos since it's obviously much more complete.
Stop me if someone's already mentioned this, but I can easily see the director thinking "Well, i want to have something familiar that's made the news recently, but i still want to get that big nifty dramatic looking sail into the movie. So that means i can't call it 'Suchomimus' without everyone jumping on me for the obviously incredibly oversized Spinosaurus-sail (as compared to the low ridge _Suchomimus_ has)... therefore..."
Further, _Suchomimus_ seems to have more classic _Spinosaurus_ shaped teeth in the dentary, though they still do look a bit more curved than that, yet it might be reasonable to guess that _Spinosaurus_'s straight tooth was from a particular part of the dentition, and teeth at the front of the dentary and on the maxilla and premaxilla were more strongly curved as in _Suchomimus_ ... i can imagine Dr Grant thinking that the tooth looked like _Suchomimus_, but in saying "Spinosaurus" was just offhandedly trying to refer to the group of animals, rather than pinning down a specific species (which i imagine would be a bit difficult in forms defined by fragmentary remains like _Spinosaurus_: unless he actually dissects the big scary thing...).
Then of course there's another consideration - surely after the ending to "The Lost World", recent history (especially in palaeontology) unfolded differently in the world of JP3 than in our world, and maybe the expedition in northern Africa dug somehwere oh-so-slightly differently than they did in our history and turned up a more complete _Spinosaurus_ with a tooth like the one Sam Neil identifies? I suppose, extending that, you could pretty much chalk up any mistake on Grant's part to him being in a parallel dinoverse, as it were.
Ok, i promise not to mention Jurassic Park again. Scout's honour.