Spinosaurus is confusing...

Hello all, today when looking at Spinosaurus, I got confused. 

There are 2 known re-creations of Spinosaurus, pre-2014 Spino,

which is shown here:

and "New Spinosaurus" 

which is also shown here: 

Which confuses me, because these are both official skeletons of Spinosaurus shown in museums. 

And yet they are drastic, how is this so? If you could please help me that would be great!

(P.S Sorry if I got any facts wrong in this.)