Board Thread:General Discussion/@comment-10906513-20150613143615/@comment-83572-20150621102433

The reason Spiny was on 2 legs is because information about Spinosaurus Aegypticus was limited at the time of the third movie's production, since the only complete skeleton to have been excavated thus far got trashed by the bombing runs on Berlin in WWII. Therefore, analysis of the complete animal was limited to what scientists could get from surviving records and from trying to reassemble the bomb-blasted bits.

The most likely reason Spinosaurus wasn't on InGen's list is that the live one was a new discovery and had yet to be confirmed as a viable specimen (instead of a short-lived false start) before Hurricane Clarissa.