Museum at Home > Fossils/Ammonite

The Lyme Bay Ichthyosaur (Temnodontosaurus platydon)

This very large Ichthyosaur was discovered within metres of Lyme Regis Museum by local collector and fossil hunter Mike Harrison in 2011. It is the same type of Ichthyosaur, as the one discovered by Mary Anning and her brother, 200 hundred years earlier in 1811.

Called Temnodontosaurus, meaning in Greek “cutting-tooth lizard”, (temno, meaning “to cut”, odont meaning “tooth” and sauros meaning “lizard”), it is on display with part of the spine, rib cage and front fins.

It lived in the Early Jurassic period, ranging between 200 and 175 million years ago in the sea that covered Lyme Regis and as far afield as the coast of Chile. It’s long slender body is described as fish-like and its’ powerful tail, almost the same length as the body, made it a fast cruising swimmer. It’s large eye socket suggests it had good eyesight and it was an apex predator, feeding on fish, plesiosaurs and other ichthyosaurs.


Ammonites are related to squids, octopuses and nautilus still living in seas around the world today. There soft body and tentacles are rarely preserved, but there iconic shell are often preserved in the rock and found on the beaches around Lyme Regis.

Their shell is a spiral shape made up of chambers, the sections grow over time as the Ammonite gets bigger. The ammonite lived in the front part of the shell and used the other spaces to hold gas and air which it used to float up and down in the sea and propel itself.

Some ammonites were tiny, others were as big as a person.

Lyme Regis is one of the best places in the UK to find ammonites and there are many wonderful examples in the museum collections.

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Carolyn KingGillian CandlerJenny PigottJo Smith OliverJulia CallejaSue Wells | Sue Wells 2Val Griffin | Zoe Smith