Liopleurodon ferox is a widely known thalassophonean pliosaurid from the Middle Jurassic (Callovian)Oxford Clay Formation of England and comparable strata in northwest France,”stated University of Portsmouth paleontologist Edward Bartlett and his associates.

“It is amongst the earliest of thalassophoneans to be understood from near-complete skeletons.”

“Consequently, Liopleurodon ferox has actually ended up being a standard for organized research studies and size contrasts of thalassophoneans. A complex taxonomic history stemming from the medical diagnosis of the holotype, a separated caniniform tooth initially explained in 1873, has actually led to the recommendation of lots of Callovian-Tithonian pliosaurid specimens to the genus.”

“This has actually led to a large range of size price quotes from 6.39 m to the amazing 25 m provided in the 1999 BBC television series Strolling with Dinosaurs“

In their research study, Dr. Bartlett and co-authors evaluated 37 specimens credited to Liopleurodon ferox

They determined an overall body length varying from about 2.46 to 8.09 m, with the more total skeletons clustering around 4.8 to approximately 6 m.

The typical animal, they concluded, was most likely near to 5 m long– still a terrifying predator, however a portion of the legendary 25-m figure.

“Our research study is the initially detailed reappraisal of every specimen appointed to Liopleurodon ferox,” Dr. Bartlett stated.

“By uniting all of the readily available product, we can lastly supply a robust price quote of its size and body percentages.”

“Although it was smaller sized than some popular restorations, it was still the dominant marine predator in the Jurassic Oxford Clay seas.”

To develop their modified design, the paleontologists turned to 2 unspoiled skeletons– one housed in Tübingen, Germany, and another at the Natural History Museum in London– together with a different, total skull utilized to adjust cranial percentages.

They discovered that the skull comprises about 24% of the animal’s skeletal length, an especially bigger share than earlier price quotes recommended, hinting that Liopleurodon ferox might deal with reasonably big victim compared to other pliosaurs living together with it.

Even reduced, Liopleurodon ferox stays the biggest recognized animal from the Oxford Clay Formation environment.

“Our research study is the initially extensive reappraisal of every specimen appointed to Liopleurodon ferox,” Dr. Bartlett stated.

“By combining all of the readily available product, we can lastly offer a robust price quote of its size and body percentages.”

The scientists likewise flag something more unexpected: numerous fragmentary fossils from the exact same rock development appear to belong to pliosaurs significantly bigger than any verified Liopleurodon feroxwith approximated lengths reaching as high as 12.2 m.

Since these specimens do not have the diagnostic functions required to designate them to a types, their identity stays a secret, though they recommend that real giants were swimming in Middle Jurassic seas together with Liopleurodon ferox

“Indeterminate Oxford Clay Formation pliosaurid specimens approximated at 7.02-12.2 m overall body length show that gigantism in pliosaurs (over 10 m) developed throughout the late Middle Jurassic,” the researchers stated.

The findings appear in the Journal of Vertebrate Palaeontology

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Edward O. Bartlett et alRe-evaluating body size in the Middle Jurassic pliosaur Liopleurodon ferox Sauvage, 1873. Journal of Vertebrate Paleontologyreleased online July 16, 2026; doi: 10.1080/ 02724634.2026.2691149