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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans
Moon crabs
Family Matutidae
updated Dec 12
Where seen? These crabs as pale and circular as a full moon are commonly encountered on our Northern shores. They are more active at night and are rarely seen by daytime visitors as they are then often buried in the sediments.

Features: Body somewhat circular with a pair of long spikes on the sides. Pincers short, sturdy, held against the body to form a somewhat box-like shape. All walking legs end in paddle-shaped tips and used to skim along the sea bottom and also like spades to rapidly burrow into the sand. With eight little spades rotating rapidly, the crab disappears into wet sand in an eyeblink. The sturdy pincers grab any edible bits that the crab can handle.

What do they eat? They eat worms, clams and other small animals, foraging more actively at night. A juicy dead fish, however, may lure them out of hiding even during the day.

Human uses: These crabs are eaten in some other countries.

Status and threats: Our moon crabs are not listed among the threatened animals of Singapore. However, like other creatures of the intertidal zone, they are affected by human activities such as reclamation and pollution. Trampling by careless visitors also have an impact on local populations.

All the legs of the Moon crab
are flattened into paddles.
Changi May, 05


About to mate?

Swarming over a recently dead fish.
Tanah Merah, Jul 10

A huge dead crab, bliss!
Changi, Oct 08

Tiny one eating an injured worm.
Chek Jawa, Feb 02

Tanah Merah, Jul 11

Buries itself in an eye blink.

Moon crabs on Singapore shores

 

Family Matutidae recorded for Singapore
from Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore
*
Tan, Leo W. H. & Ng, Peter K. L., 1988, A Guide to Seashore Life.
**
Ng, Peter K. L. and Daniele Guinot and Peter J. F. Davie, 2008. Systema Brachyurorum: Part 1. An annotated checklist of extant Brachyuran crabs of the world.
+added from our observation

  Family Matutidae
  *Ashtoret lunaris (Spotted moon crab)

+Matuta planipes (Reticulated moon crab)

Links

References

  • Ng, Peter K. L. and Daniele Guinot and Peter J. F. Davie, 2008. Systema Brachyurorum: Part 1. An annotated checklist of extant Brachyuran crabs of the world. The Raffles Bulletin of Zoology. Supplement No. 17, 31 Jan 2008. 286 pp.
  • Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life and Times of Labrador Beach. Division of Biology, School of Science, Nanyang Technological University & Department of Zoology, the National University of Singapore. 160 pp.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Nature Society (Singapore), Singapore. 343 pp.
  • Jones Diana S. and Gary J. Morgan, 2002. A Field Guide to Crustaceans of Australian Waters. Reed New Holland. 224 pp.
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