Was Spinosaurus quadrupedal or bipedal?

The anatomy of Spinosaurus is more well constrained than Matt Moore suggested in the previous answer. Here´s somewhat how it goes: After the initial publication in 2014, some paleontologists, among which Scott Hartman and Mark Witton made some criticisms about the reconstruction of the newly found specimen. read more

The Spinosaurus was an obligate biped. This is for a variety of reasons, all of its relatives were obligate bipeds, and if you look at the structure of the arms, they were not built for walking. read more

It is driven by the hind limbs but it is really hard to call it bipedal. read more