Oxalaia Quilombensis

Oxalaia is a genus of Giant Spinosaurid from the Late Cretaceous of Brazil. The name Oxalaia is a reference to the African Deity Oxala. Oxalaia was discovered in 2004, in the   Alcantara Formation, part of the São Luís Basin. If they had not found parts of the long crocodile like snout, and instead found an arm, it would have been easy to identify the remains of the large Carcharodontosaur Mapusaurus that lived at the same time.

Late Cretaceous Brazil was a predator hotbed. It is chalk full of gigantic predators, many over thirty feet long. Among them, the forty foot long Oxalaia, the previously mentioned Mapusaurus, the equally as enormous Tyrannotitan,and the giant Abelisaur Ekrixinatosaurus. Oxalaia Evolved in a way to avoid competition, it took to the water. The large fish and small crocodiles of the time were basically predator-less, and Oxalaia evolved to fill that niche. It's long, thin snout was ideal for snagging the fish and crocodiles from the rivers.

This isn't to say it didn't attempt land based prey, though. Being so large, and being equipped with deadly weapons, it could take small herbivores if it pleased. A recent fossil find revealed a spinosaur tooth in the vertabrate of a pterosaur, suggesting the Spinosaurs of Brazil didn't only eat fish. Oxalaia could use its enormous size to scare rival theropods from their kills. If they picked the wrong fight though, The outcome wouldn't be in the Spinosaurs favor. The vunerable sail would have been a target, so Oxalaia would stick to the rivers for the most part.