Olorotitan vs. Liaoningosaurus
It is the Late Cretaceous period, where one day the Tsagayan Formation will reside in Far Eastern Russia. A vast wetland sits in a low point in the land, fed by streams and rivers coming down from the adjacent uplands, with one particularly large tributary. Where this tributary meets the wetland there is a deep pool and an abundance of inflowing nutrients, the perfect spot for fish to congregate. The fish share this wetland with turtles and crocodiles, small mammals and large hadrosaurs. It is into this ecosystem that Liaoningosaurus, a tiny ankylosaur, arrives from 60 million years in the past.
As a semi-aquatic animal, Liaoningosaurus is comfortable enough on the foreign field. As a piscivore (fish eater) she readily takes to the available body of water and goes hunting for a meal (Ősi at al. 2017).
As Liaoningosaurus slips into the water, the sound of a long bellowing call stretches across the surface of the wetland. A distant call answers in response. The source of the first call, Olorotitan reaches her head high up out of the water plants to hear her caller better.
With 18 neck vertebrae, more than any of her other hadrosaur cousins, she can see far off into the distance and make out the distinctive hatchet shaped crest of a male Olorotitan (Godefroit et al, 2003). The new spring marks the start of the mating season, but also the emergence of new spring growth. The female Olorotitan has found a particularly tasty patch of horsetails, and while she will signal to her potential suitor, she will wait for him to come to her.
Spring has brought other changes, as yet unfelt in the low-lying wetland ecosystem. Upstream and uphill, spring storms have dropped their precipitation on the uplands. This water has come rushing down the main tributary, but has been temporarily contained upstream of the wetland by a damming log jam. However, the pressure has been building, and it’s only a matter of time before the water bursts over or through its temporary constraint.
Down in the wetland, Liaoningosaurus is diving eagerly for fish. When successful, she laboriously drags her spoils through the plants where Olorotitan is grazing, and up the banks to dry land for eating. Wary of the much larger animal, Liaoningosaurus tries to give Olorititan a wide berth as she slips back into the water, heading deeper into the pool. She has to fight to stay in the pool, as the current of the inflowing tributary has picked up with unexpected speed and force. Upstream, the dam has burst, sending a wall of water and logs thundering towards the wetland. The sound is colossal, and the animals at the mouth of the tributary scramble away from the oncoming debris.
Olorotitan, 8 meters long and already near the bank, has but to turn and give a few powerful kicks of her back legs to make safety. Liaoningosaurus is not so lucky. In her rush to escape the oncoming deluge, Liaoningosaurus attempted the most direct route to safety, a trajectory that led her straight into Olorotitan’s kicking legs. One of Olotitan’s feet connects hard, sending Liaoningosaurus tumbling backwards just as a large log is swept into the wetland. The log rolls over Liaoningosaurus, pinning the animal to the bottom of the wetland. Semi-aquatic she may be, but able to breath under water she is not.
On the shore Olorititan shakes herself off. Perhaps she will go in search of her potential paramour after all.