I recently reread Michael Crichtion's Lost World (better than the movie)
Aint it always the way.
D20 Modern has a set of stats. I’ll never forget their faces when I casually mentioned Jurassic Park.
It will need some adjustments though. For life blood points use it’s Con score + 10 due to size. I didn’t do that, and the dinos got slaughtered,

Change defense to AC and your all set.
HD 4-8D8+12, LB 27, Init +2, Spd 60ft, Defense/ AC 16, AR 5, BAB +6, Atk (rake 2D6+2) (foreclaw 1D3+2) (bite 2D4+2). FS (fighting space) 10x10 ft, SV Fort +7, Ref +6, Will +2, Str 19, Dex 15, Con 17, Int 2, Wis 12, Cha 10,

don't ask me to explain that one.
Skills. Hide +7 Jump +13, Listen +11, Spot +11, Survival +9
Feats, low-light vision