Bivalve shell

The fossil that defines a species

This fossil is a holotype; the specimen that defines this species. If someone wanted to check the validity of this species, or compare it to a similar specimen, they would start with this specimen as it defines Lima (Ctenoides) cunningtoni. The name already tells us that has happened once before; the genus name Ctenoides in brackets, means that was the original genus assigned to this specimen. But following research and comparative studies with other fossils, it was given a new name, Lima, to reflect a more recent understanding of the evolution of this genus. That could happen again. One of the main roles of the museum is to safeguard this specimen for future study.

Find out more about bivalves on the molluscs pages.

Common name

Bivalve shell

Scientific name

Lima (Ctenoides) cunningtoni


Molluscs > Bivalves


Portland Limestone

Time period

Upper Jurassic


150 million years

Where found

Isle of Portland {module Portland Quarries safety warning}

Found by



Dorset County Museum, Dorchester

Accession number