PDBCCR1F5: Spinosaurus vs Oxalaia

(Note - this fight is canon in the Isla Nublar Apocalypse universe.)

In the swamps of Isla Nublar, an alpha-Spinosaurus, Fang, the son of the legendary Egypt, was fishing for food. His mate, Venus, was resting, so he decided that he would catch some fish for both his mate and himself. He stepped into the river, then, when it was deep enough, began to swim, clamping his jaws around any fish in his sight. He left some of his catches on the shore for his mate, and returned to the river.

***

A few miles away, in this same swamp, a mated pair of Oxalaia were looking for a new territory, having lost their old hunting-grounds to a pack of Giganotosaurus. They were also hungry, but hadn't found any food. However, they stumbled upon a pile of sawfish, and began to eat some of them.

***

Fang returned to the banks of the river to see two Oxalaia eating the fish he had left there. He released a roar of anger, to assert his dominance to the Brazilian piscivores. They hissed back at him, having strength in numbers. Fang, however, wasn't going down easily, and almost immediately slashed at the male's snout, drawing blood. The fight had begun.

In an attempt to scare the two away, Fang released a gluttural bellow, also trying to show that he was the dominant predator of these swamps. The two Oxalaia stood their ground and approached Fang.

The male clamped onto the neck of the Spinosaurus, who hissed more in annoyance than in pain. He pushed off the Oxalaia before cutting his flesh with his claws, leaving deep cuts in his neck. The female intervened, charging Fang, and sending him into a tree, before the male slashed at his torso. Fang bit onto the female's neck while slashing at her face and torso, causing her to bellow in pain as blood dripped down her massive body. He refused to release his grip, as the male silently crept into the water, submerging himself.

Fang suddenly felt something grab his tail and pull back, forcing him to let go of the female. The male Oxalaia then pulled Fang towards him, biting down on his neck. Knowing he wouldn't let go, the Spinosaurus threw himself into the river, taking the male with him--and an underwater duel commenced.

The two kicked and clambered, their sails the only visible parts of their bodies. Underwater, Fang and the male used their claws to slash at each-other. The South American Spinosaurid used his smaller size to his advantage, using hit-and-run tactics, striking Fang with his claws. At one point, he severed a major artery in the right leg of the Spinosaurus.

The male spun around in an attempt to disorient the Spino with a tail-slap, but Fang pulled his head back before sinking his conical teeth into the tail, refusing to let go. As he immobilised him with his jaws, he slashed at the tail with his claws, sending the Oxalaia into severe shock and blood loss. Fang did this continually, pulling him out of the water by his tail. From there, he continually shredded the male's tail using his claws, with no let-up as the Oxalaia struggled to keep his head above the water. Eventually, he tore his tail clean off, throwing it into the water.

***

In the swamp, a legendary alpha-Spinosaurus saw the battle, recognising his son among the chaos.

Fang dipped his head underwater to pick up the tailless theropod, before cutting his jugular vein and killing him. He limped back to the shore, before collapsing from exhaustion and blood loss. The female towered over him, preparing to kill him, when another roar got her attention. She looked in horror, to see Fang's father, Egypt. The alpha-Spinosaurus roared in anger before slashing at her with his claws. The Oxalaia bit down on his snout, opening up an old wound inflicted by Titanic the Tyrannotitan. Egypt bellowed in pain, before stomping upon her skull, flattening it like a pancake under his foot.

Fang stood to his feet and chirped to his father, thanking him.

Winner: Spinosaurus!

Just to clarify, Egypt, despite being smaller, is still stronger than Fang. The former could've killed both Oxalaia on his own.