The oldest megapredatory pliosaur, Lorrainosaurus, in the ancient Middle Jurassic sea that covered what is to day northern France 170 million years ago. Credit: Joschua Knüppe
Key points:
- Fossils found 40 years ago have been identified as belonging to a new pliosaur genus: Lorrainosaurus.
- Lorrainosaurus is the oldest large-bodied pliosaur represented by an associated skeleton.
- The recovered bones and teeth of Lorrainosaurus represent remnants of what was once a complete skeleton that decomposed and was dispersed across the ancient sea floor.
The fossils of a 170-million-year-old ancient marine reptile from the Age of Dinosaurs have been identified as the oldest-known mega-predatory pliosaur, a group of ocean-dwelling reptiles closely related to the famous long-necked plesiosaurs.
The fossils were found 40 years ago in north-eastern France. An international team of paleontologists have now analyzed them and identified them as a new pliosaur genus: Lorrainosaurus. The findings are rare and add new knowledge to the evolution of plesiosaurs, according to the paper published in Scientific Reports.
Lorrainosaurus is the oldest large-bodied pliosaur represented by an associated skeleton. It had jaws over 1.3 m long with large conical teeth and a bulky “torpedo-shaped” body propelled by four flipper-like limbs. This giant reptile probably reached over 6 m from snout to tail, and lived during the early Middle Jurassic period. In general, pliosaurs were some of the most successful marine predators of their time.
“They were ecological equivalents of today’s killer whales and would have eaten a range of prey including squid-like cephalopods, large fish and other marine reptiles. These have all been found as preserved gut contents,” said senior co-author Benjamin Kear, Curator of Vertebrate Paleontology and Researcher in Paleontology at Uppsala University.
The recovered bones and teeth of Lorrainosaurus represent remnants of what was once a complete skeleton that decomposed and was dispersed across the ancient sea floor by currents and scavengers.
Other than a brief report published in 1994, the fossils of Lorrainosaurus remained obscure until this new study re-evaluated the finds. Lorrainosaurus indicates that the reign of gigantic mega-predatory pliosaurs must have commenced earlier than previously thought, and was locally responsive to major ecological changes affecting marine environments covering what is now western Europe during the early Middle Jurassic.
“Lorrainosaurus is thus a critical addition to our knowledge of ancient marine reptiles from a time in the Age of Dinosaurs that has as yet been incompletely understood,” said Kear.