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Phylum Mollusca > Class Bivalvia > Family Osteridae
Zig zag oyster
awaiting identification*
Family Ostreidae
updated May 2020
Where seen? This oyster with a zig-zag opening at the valves is sometimes seen on some of our shores, on boulders and seawalls. Usually a few are squished in cracks near the mid water mark.

Features: 3-8cm. The two-part shell is thick and chalky. The opening between the valves is a regular fine zig-zag. The opening is usually well away from the rock surface. Some are crowded next to one another, others are found singly.

Oysters are difficult to distinguish by shell shape alone and those on this page may in fact be different species that appear similar.

Raffles Lighthouse, Aug 06

Kusu Island, Jun 05

*Species are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.

Zig zag oysters on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Sentosa Serapong, Dec 20
Photo shared by Vincent Choo on facebook.

Lazarus, Nov 20
Photo shared by Vincent Choo on facebook.

Pulau Tekukor, Jun 16
Photo shared by Ian Siah on facebook.

Pulau Jong, Aug 21
Photo shared by Vincent Choo on facebook.

Pulau Biola, May 10
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