Ammonite

Additional images

Subtle differences that define species

This ammonite is strikingly similar to Mantelliceras (G.09723 also pictured), but look carefully and you’ll notice that the ribs in this specimen split or ‘bifurcate’ whereas the ribs on Mantelliceras form single, solid ribs that run all around the outer edge. Both are also similar to Calycoceras (gentoniceras) gentone but this ammonite has tubercles or spines on top of the ribs.

Find out more about ammonites on the molluscs pages.

Common name

Ammonite

Scientific name

Acantheoceras

Type

Molluscs > Cephalopods


Strata

Chalk, Lower

Time period

Upper Cretaceous

Age

96 million years

Where found

Unknown

Found by

Unknown

Museum

Dorset County Museum, Dorchester

Accession number

DCM.G.08200