Recently there has been a study on Spinosaurus legs that shows that he couldn’t support the weight he has on such short legs and that legs must have been 4 times bigger in order for him to function properly. So the small legs were probably from totally different species mixed with Spino skeleton or a juvenile.
Finally he is back to normal.
No, the tail is recent, short legs are a thing since about 2014 and it didn’t make any sense to me either, now I know why.
Its such a weird mishmash thing, like a prehistoric platypus. How does it even function