Reptilian suction feeders were few and far between during the Mesozoic Era, or so paleontologists had thought.
A unique 67-million-year old turtle that had a mouth reminiscent of a swordfish’s and fed by way of suctioning has been uncovered in Western Morocco.
Ocepechelon bouyai was unlike any other scientists know of: it had a particularly large skull and a long tube-like snout used for suction feeding. Researchers led by Nadia Bardet from the Muséum National d’Histoire Naturelle, in Paris, France, analyzed the fossil turtle skull for clues as to how Ocepechelon survived in the prehistoric seas of northwestern Africa.
Ocepechelon’s skull sported an unusually-shaped beak – indicative of the evolutionary shift of many Mesozoic reptiles from terrestrial to aquatic life. The Mesozoic Era, lasting from 250 to 65 million years ago, witnessed the arrival of a number of reptilian lineages to ocean environments. Ocepechelon most likely had land-living roots, and over time became well-adapted to a new, aquatic habitat by means of a feeding habit not at all common for Mesozoic reptiles: suction feeding.
Many living aquatic vertebrates, including walruses, whales, and some freshwater turtles; acquire food through suction feeding – ingesting prey with large amounts of water by creating a pressure difference between an expanded oral cavity and the surrounding water.
Ocepechelon, one of the largest marine turtles ever, had a 70-cm-long-skull that showed unique adaptations for suction feeding.
Ocepechelon used flippers to swim, skimming the surface of the water searching for small swimming prey, much like how crocodiles peek just over the surface of water bodies today. Nostrils on the top of its flat, streamlined, beak would have allowed Ocepechelon to breathe while still swimming.
Its upper jaw showed no evidence of cutting or chewing teeth, indicating that Ocepechelon did not bite its prey. Instead, Ocepechelon used a long, thin, tubular, bony snout that had a small round opening at the end for suctioning water containing small fish, cephalopods, and jellyfish into its mouth. It sucked large amounts of water in through this opening, trapping small animals within the water, then closing its mouth to swallow, and finally forcing out the excess water. The long beak combined with a small mouth gap is an adaptaive characteristic that allows certain marine animals, such as pipefish, to reach their prey faster – the oral cavity can reach prey in less time that it would take the rest of the body to. It also allowed Ocepechelon to draw in water in at a high speed, so prey couldn’t escape easily.Ocepechelon represents the only tetrapod (four-limbed vertebrates) ever discovered to have been a bony-pipette feeder.
Ocepechelon’s remains supplement the growing body of evidence that suggests a vast diversity of marine life just prior to the Cretaceous-Paleogene extinction event.
Ocepechelon was described on July 11 in PLOS ONE.