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Jurassic-age giant reptile was twice as big as killer whale

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May 18, 2023

Giant reptile: Large gray beast with long tail and 2 fins swimming beside a person for scale. — This giant reptile of the Jurassic age – the pliosaur – was twice the size of a killer whale. Megan Jacobs, an author of the study, also created this artist’s concept of the pliosaur. Additionally, a human has been added for scale. Image via University of Portsmouth/ Megan Jacobs.

Giant reptile swam in Jurassic seas

Scientists examining fossils at Abingdon County Hall Museum in England came upon four large vertebrae from the Jurassic age. Initially, these fossils came from an excavation at the River Thames Valley in Oxfordshire. They are in a clay deposit that dates to the Late Jurassic, some 152 million years ago. The scientists, led by David Martill and Megan Jacobs of the University of Portsmouth, identified them as closely related to pliosaurs. Then, on May 10, 2023, they announced that these large bones indicated that pliosaurs could have been as large as 47 feet (14.3 meters). As Martill said:

It’s wonderful to prove there was indeed a truly gigantic pliosaur species in the Late Jurassic seas.

The scientists published their peer-reviewed research in the journal Proceedings of the Geologists’ Association on May 10, 2023.

Portsmouth palaeontologists have found four ENORMOUS vertebrae, which prove that #pliosaurs could have grown to twice the size of a killer whale! #fossilfriday #fossils #palaeontology @portsmouthuni

Read the full story here: https://t.co/OrdmVMW6zR pic.twitter.com/RuPsW6oAyK

— University of Portsmouth News (@UoP_Media) May 12, 2023

What are pliosaurs?

Generally speaking, pliosaurs are prehistoric reptiles that were similar to plesiosaurs, a common marine reptile of the time period. However, pliosaurs had a bigger, elongated head with a shorter neck. Also, they sported four flippers and a short tail to help them paddle and maneuver through the seas.

The team used topographic scans to calculate a size range for pliosaurs of 32 to 47 feet (9.8 and 14.3 meters). Indeed, as you can see from the chart, this length would put them in the range of today’s whale sharks and larger.

Shadowed images of marine life such as sharks and the pliosaur compared by size. — This chart compares the size of marine life we are familiar with today and the prehistoric reptile known as a pliosaur. These giant sea creatures lived in the Late Jurassic age. Image via University of Portsmouth/ Proceedings of the Geologists’ Association/ David Martill.

Pliosaurs ruled the seas

Martill describes these prehistoric reptiles:

We know these pliosaurs were very fearsome animals swimming in the seas that covered Oxfordshire 145-152 million years ago. They had a massive skull with huge protruding teeth like daggers, as big – if not bigger than – a T. rex, and certainly more powerful.

But, despite it living in the Jurassic age and the comparison with a T. rex, Martill cautioned:

Please do not call it a dinosaur. That would be like calling a mouse cattle or a cat an elephant.

So, these prehistoric reptiles were larger than scientists previously thought and were dominant in Jurassic seas. As Martill said:

They were at the top of the marine food chain and probably preyed on ichthyosaurs, long-necked plesiosaurs and maybe even smaller marine crocodiles, simply by biting them in half and taking chunks off them. We know they were massacring smaller marine reptiles because you can see bite marks in ichthyosaur bones in examples on display in The Etches Collection in Dorset.

Bottom line: Scientists have discovered that giant reptiles of the Jurassic period – known as pliosaurs – could have been up to 47 feet in length.

Source: A truly gigantic pliosaur (Reptilia, Sauropterygia) from the Kimmeridge Clay Formation (Upper Jurassic, Kimmeridgian) of England

Via University of Portsmouth

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May 18, 2023

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Kelly Kizer Whitt

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About the Author:

Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. She began her career at Astronomy Magazine, and she has made regular contributions to AstronomyToday and the Sierra Club, among other outlets. Her children’s picture book, Solar System Forecast, was published in 2012. She has also written a young adult dystopian novel titled A Different Sky. When she is not reading or writing about astronomy and staring up at the stars, she enjoys traveling to the national parks, creating crossword puzzles, running, tennis, and paddleboarding. Kelly lives with her family in Wisconsin.