Descent into Carnivory: How Large Vertebrate Suspension-Feeding in the Mesozoic Ran Out of Options
Published 2024-04-16
In the modern world, the niche of large vertebrate suspension-feeding is exemplified by filter-feeding whales and chondrichthyans like the basking shark and whale shark, which have specialized feeding structures for plankton. The fossil record shows that similar feeding structures are apparent as far back as the Jurassic in a group of bony fishes called pachycormids, as best represented by Leedsichthys (estimated to have grown up to 16.5 metres). These large suspension-feeding pachycormids arose in the Early Jurassic, simultaneous to the appearance of large herbivorous terrestrial animals—the sauropod dinosaurs—paralleling their gigantism. Research conducted at the Royal Tyrrell Museum of Palaeontology over the last three years has shown that although the suspension-feeding pachycormids continued into the Late Cretaceous, their numbers and relative diversity declined until they secondarily diversified back into carnivory, from which they had first arisen 100 million years earlier.