Irritator vs Patagotitan
110 Million years ago in early Cretaceous Argentina, on an open floodplain of braided river channels and low vegetation, Irritator arrives from Brazil of the same time period.
Rather than roam the flood plain flats, exposed and snapping after small strange prey, Irritator climbs down into a river channel in search of familiar quarry. The spring floods have subsided, leaving steeply eroded banks and river waters that are beginning to run clear. In the deeper pools, the flash of swimming fish can be seen from the surface, attracting the eye and appetite of Irritator. Ever the patient hunter, Irritator waits poised over the river, careful not to cast a shadow over the water. When a fish rises to gulp one of the insects on the surface of the water, Irritator’s head snaps down preternaturally (Schade et al. 2020). The fish is out of the water and in the hunter’s mouth; the first catch of many.
Up on the flood plain, Patagotitan is following the path of the river channel upstream towards the tree line. The sun is beating down, and the shade and foraging potential of the forest are beginning to look particularly appealing. He picks his way carefully along the bank, avoiding debris and keeping space between itself and the edge of the bank. As Patagotitan approaches the place where Irritator fishes happily it makes no effort to swerve away or avoid the strange new in its habitat. At 40 meters in height, Patagonian has nothing to fear from a substantially smaller predator that is already immersed in pursuing other prey.
However, Irritator cannot ignore Patagotitan as it passes above him. He looks up just in time to see the deeply eroded shelf under Patagotitan’s left front foot giving way, pitching 70 tons of sauropod off kilter and right on top of Irritator. The spinosaur has no time to react, and Patagotitan lands with a splash and a sickening crunch of bone.
Patagotitan is the first to right itself, hampered by the flailing limbs of Irritator and its inability to find stable footing on the rocks and silt of the river bottom. With much effort, the dinosaur painstakingly heaves itself to its feet, feeling the impact of its fall in the bruising of its ribs and the damage done to its left front leg that had folded beneath it. It limps out of the river and up the bank without a backward glance.
Irritator might feel some relief at being freed from the crushing weight of Patagotitan, if only its mind were not distracted by the excruciating pain of a broken pelvis. Perhaps, with luck, this spinosaur will be able to extricate itself from the water, heal, and survive. Without luck, it will likely die in the river from drowning or starvation. Its body might be swept down river, disarticulating in travel before being buried, to become one of the many unassociated fossils found by modern paleontologists. Who knows?