Skip to content
You are here: Home | All | Visit | Fossil stories

Fossil stories

A magnificent marine reptile from the Mesozoic

Grey shape with snout pointing towards the right of image and white band accross centre.


What are Ichthyosaurs?

Ichthyosaurs were giant marine reptiles which evolved during the Triassic period, the very start of the Mesozoic approximately 250 million years ago and were a very successful group. The name ichthyosaur means ‘fish-lizard’ and was coined in 1834. These wondrous sea-dragons were made sensationally aware to the public when Mary Anning discovered a skeleton at Lyme Regis in 1811. Other skeletons had been found prior, but this was the first to come to the attention of the scientific circles in London. The specimen was purchased and put on display in London. Since then many discoveries have been made by palaeontologists and the public which have made their way into collections by generously donating them to museums.

Where was our Ichthyosaur found?

This Ichthyosaur rostrum or jaw was acquired by Beeby Thompson and donated with the rest of his collection to the museum. This jaw was originally found with over 100 other fossilised bones in a brick yard at Easton Neston in 1921.

What did they look like?

Popular documentary series such as ‘walking with Dinosaurs’ have depicted ichthyosaurs as very similar to dolphins and sharks. Early ichthyosaurs however were very diverse in form but over millions of years they became very similar to marine mammals. This is a form of convergent evolution where two similar organisms which are unrelated evolve similar forms to fill similar roles within the ecosystem.

How long ago did they live?

The specimen here is likely to be from the Jurassic period and lasted about 50 million years from 201 to 145 million years ago. Geologists use a geological time scale to describe the events and relationships found within the bedrock beneath our feet and it is divided up into supereons, eons, eras and periods. The Mesozoic era occurred approximately 250 million years ago and lasted until 65 million years ago when a meteorite crashed into the earth wiping out the dinosaurs, pterosaurs and many marine reptiles which thrived in the oceans.