About 130 million years ago, in what is now central Colombia, the oceans were filled with a diversity of species not found today. In the water swam a few gigantic, nightmarish apex predators. These marine reptiles can reach lengths of 2 to 10 meters (approximately 6 to 32 feet) and some have huge mouths filled with teeth, while others are mounted on long snake-like necks. Some have a relatively small head (also full of teeth) that is cut into pieces.
These giants shared the oceans with countless smaller species, many of whom were predators. These included ichthyosaurs, dolphin-like reptiles, as well as at least one species of turtle, fish, ammonite, crab, mollusk, shark, and crocodile type.
It must have required a thriving ecosystem at every level to allow all these creatures to thrive. Thanks to discoveries in something called the Paja Formation, a fossil-rich and exquisitely preserved treasure trove, researchers now understand how ecosystems support so many apex predators. And we may find hints at how the Jurassic period thrived shortly after it was brought to an end by a mass extinction.
who ate what
Dirley Cortés is a PhD candidate at McGill University’s Red Path Museum, a postdoctoral fellow at the Smithsonian Tropical Research Institute, and a researcher at the Center for Paleontological Research (CIP). She presented the data she and her team have been working on from the Paja layer at her 2022 Annual Meeting of the Society for Vertebrate Paleontology (SVP) in Toronto last November.
The team’s goal is to delve deeper into the role each species played in the ancient oceans. In other words, they want to determine the ecological niche of each species, from apex predators to the tiniest species in the ocean. For example, not all species fossilize, and few provide gut contents that indicate what they ate. So how can scientists recreate extinct ecosystems?
Acknowledging the limitations of these studies, the team compared the size, dental aspects of each species, and other attributes to analyze where they fell in this early Cretaceous food chain. “This is,” Cortez explained. This is the starting point for developing an energy flow model. “
“This trophic food web has been quantitatively reconstructed based on putative trophic interactions of marine producers, consumers and large apex predators,” she added.
