Brittle Star

Caught in a storm?

This near-perfect brittle star comes from the ‘Starfish Bed’ between Eype and Seatown. Hundreds of similar fossils have been recovered from huge fallen blocks on the beach for more than two centuries. Many, like this one, have some or all legs pointing or trailing in one direction. This suggests that there was a current flowing across the sea floor when these animals were buried, from right to left in this image.

It has been speculated that a storm, or even a tsunami, smothered a whole community of brittle stars in a single event, capturing a moment in time about 180 million years ago.

There are also exceptions to the rule. Some brittle stars are preserved with little alignment of the legs, or occasionally with four legs trailing and one pointing in the opposite direction. Brittle stars today can move across the sea bed with their legs arranged in that way.

The starfish bed is typical of many features in geology which offer different, and sometimes even contradictory evidence. This is a challenge for geologists when trying to understand and interpret past environments.

 

 

Find out more about brittle stars on the echinoderms pages.

 

 

Common name

Brittle Star

Scientific name

Palaeocoma egertoni

Type

Echinoderms > Starfish


Strata

Starfish Bed, Eype Clay, Middle Lias

Time period

Lower Jurassic

Age

188 million years

Where found

Seatown

Found by

Unknown

Museum

Dorset County Museum, Dorchester

Accession number

DCM.G.01244