Elongated toothed oyster
Isognomon isognomum
Family
Pteriidae
updated
May 2020
Where
seen? Like tongue depressors, these narrow long clams are
sometimes seen stuck upright to rocks and coral rubble near reefs.
Features: 10-15cm.
The two-part shell is thick, flat and usually long and narrow, sometimes
with a T-shape near the bottom where it is stuck to a hard surface
with byssus threads. Usually dark, the shell is often coated with
encrusting organisms. Often found in groups of a few individuals stuck
in crevices.
Sometimes confused with Hammer oysters that have a similar shape and also stuck upright
in crevices. It is difficult to tell them apart without ripping them
out of their hiding place and looking at the inside of the shell.
On the inside, Elonged toothed oysters have a long row of notches at the
hinge, and a large area of mother-of-pearl relative to the shell length. |
A large area of mother-of-pearl
relative to shell length.
Tanah Merah,
Dec 09 |
A long row of notches at the hinge.
|
Terumbu Semakau,
Nov 12 |
Beting Bemban
Besar, Aug 12 |
A long row of notches at the hinge. |
*Species are difficult
to positively identify without close examination.
On this website, they are grouped by external features for convenience of
display.
Elongated toothed oysters on Singapore shores |
Other sightings on Singapore shores |
Terumbu Raya, Aug 21
Photo shared by Vincent Choo on facebook. |
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Links
References
- Tan Siong
Kiat and Henrietta P. M. Woo, 2010 Preliminary
Checklist of The Molluscs of Singapore (pdf), Raffles
Museum of Biodiversity Research, National University of Singapore.
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