APHOTOMARINE

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.

A-P-H-O-T-O Wildlife Stock Image Library
Isognomon radiatus (Anton, 1838) - Radial purse-oyster or Lister's tree oyster - a non-native species
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Radial purse-oyster
Isognomon radiatus
- large 50mm specimen 1

Radial purse-oyster
Isognomon radiatus
- flotsam 1

A non-native species, specimen above was found on a piece of plastic flotsam washed-up at Par Beach, near St. Austell, Cornwall, 31.01.16. About five or six of the bivalves Isognomon bicolor, one Anomia simplex and one Ostrea equestris were also found on the same item of flotsam.

Radial purse-oyster
Isognomon radiatus
- exterior of valve 1

Specimen above was found on the rim of a plastic pail with (spout w/tear tab and gasket) lid, that had washed-up at Marazion, Cornwall, 30.12.15. The drum had drifted across the Atlantic from Florida. The bivalve Isognomon bicolor, the Bicolor purse-oyster was also found on the container, along with two specimens of a Floridan oyster species.

Radial purse-oyster
Isognomon radiatus
- exterior of valve 1

Radial purse-oyster
Isognomon radiatus
- exterior of valve 2

Radial purse-oyster
Isognomon radiatus
- exterior of valve 3

Radial purse-oyster
Isognomon radiatus
- valves from above 1

Radial purse-oyster
Isognomon radiatus
- hinges of both valves 1

Radial purse-oyster
Isognomon radiatus
- item of flotsam 1

Radial purse-oyster
Isognomon radiatus
- item of flotsam 2

A non-native species; one complete dead shell, about 13mm in length was found between the end of an internal thread and an "O"-ring seal in a large plastic tank or drum cap. The object was found on the strandline at Marazion, Cornwall. 07.12.15.

The species was kindly identified by Peggy Williams of Shelltrips.com

Isognomon radiatus Radial purse or Lister's tree oyster Marine Bivalve Images
The main objective of this website is in furthering environmental awareness and education through the medium of photography. To increase awareness and access to the wildlife of the region and help
people find and identify it. Sometimes the difference between species is obvious but many species can only be determined by observing microscopic characteristics that are specific to any one species.