Jurassic Pliosaur Liopleurodon Was Big, but Not as Big as Once Feared

Key Points:

• New research from the University of Portsmouth re-evaluated all known specimens of Liopleurodon ferox, concluding the marine reptile was significantly smaller than the previously claimed 25 meters, with an average length close to 5 meters.
• The study analyzed 37 specimens and found that more complete skeletons ranged from about 4.8 to 6 meters, with the skull comprising about 24% of total body length, indicating Liopleurodon ferox was still a dominant apex predator capable of tackling large prey.
• Despite being smaller than some past reconstructions, Liopleurodon ferox remains the largest confirmed animal from the Jurassic Oxford Clay Formation ecosystem.
• The researchers also discovered fragmentary fossils suggesting the presence of even larger pliosaurs in the same Middle Jurassic seas, with estimated lengths up to 12.2 meters, indicating that gigantism in pliosaurs evolved earlier than previously thought.
• These findings were published in the Journal of Vertebrate Paleontology, providing a comprehensive reassessment of Liopleurodon ferox’s size and body proportions and highlighting the diversity of large marine predators in its environment.