I felt the need to tweak the Spinosaurus stat block a bit to take into account the new findings that have been released. Full thing is here.
Spinosaurus CR 11
XP 12,800
N Gargantuan animal
Init +6; Senses low-light vision, scent, tremorsense 60 ft. (in water only); Perception +25
DEFENSE
AC 24, touch 8, flat-footed 22 (+2 Dex, +16 natural, -4 size)
hp 170 (20d8+80)
Fort +16, Ref +16, Will +9
OFFENSE
Speed 20 ft., swim 40 ft.
Melee bite +23 (2d8+12/19-20 plus grab), 2 claws +23 (2d6+12)
Space 20 ft.; Reach 5 ft. (20 ft. with bite)
Special Attacks lunging bite, power attack (-4 to hit, +8 damage), swallow whole (2d8+12, AC 18, 17 hp)
STATISTICS
Str 34, Dex 15, Con 18, Int 2, Wis 13, Cha 13
Base Atk +15; CMB +31 (+35 grapple); CMD 43
Feats Critical Focus, Diehard, Endurance, Improved Critical (bite), Improved Initiative, Iron Will, Lightning Reflexes, Power Attack, Skill Focus (Perception), Staggering Critical
Skills Perception +25, Swim +28
SQ hold breath
SPECIAL ABILITIES
Lunging Bite (Ex)
Once per minute, a spinosaurus can extend the reach of its bite attack by 5 feet without taking the normal penalties to AC associated with the Lunge feat. This extended reach applies only to the dinosaur’s bite attack and lasts until the start of the creature’s next turn.
ECOLOGY
Environment warm swamps and rivers
Organization solitary, pair, or pack (3-6)
Treasure none
At 60 ft. long, Spinosaurus is the largest predatory dinosaur. It lives a primarily aquatic lifestyle, its body well-built for stalking the muddy rivers and swamps where it dwells. It is somewhat less maneuverable on land, where its short hind legs and long torso and neck force it to walk mainly quadrupedally. Its long, conical teeth and sharp, grasping claws are ideal for catching large fish and wrangling with sea monsters, but Spinosaurus is an opportunistic predator and will eat anything that it can catch. Riverboat captains that work near Spinosaurus territory know to stay clear of the water when the dinosaur’s massive sail is spotted.