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Phylum Arthropoda > Subphylum Crustacea > Class Malacostraca > Order Decapoda > Brachyurans > Family Matutidae
Spotted moon crab
Ashtoret lunaris
Family Matutidae
updated Dec 2019

Where seen? This spotted moon crab is commonly encountered on our shores. Sandy silty shores, especially near seagrasses. It is more active at night and is rarely seen by daytime visitors as it is then often buried in the sediments. 'Lunaris' in Latin refers to the moon.

Features: Body width 3-8cm. Body rather circular, with a pair of long spikes on the sides. There are six large smooth bumps in the middle of the body, the bumps are sometimes but not always highlighted by body patterns. Colours beige to yellow with little maroon dots evenly sprinkled on the body surface, sometimes highlighting the six bumps. 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. Some may have large dark blotches on the paddles, with smaller dark spots on the legs.

Changi, Apr 05

Changi, Apr 10

Sisters Island, Oct 06

Spotted moon crabs on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Sentosa Serapong, May 24

Photos shared by Ng Leekiang on facebook.

St. John's Island, Jul 09

Photos shared by Geraldine Lee on her blog.

St. John's Island, Oct 20

Photos shared by Jianlin Liu on facebook.

With eggs.
St. John's Island, Feb 24

Photos shared by Marcus Ng on facebook.

Punggol, Jan 13
Photos shared by Loh Kok Sheng on his blog.

Cyrene Reef, Feb 16
Photos shared by Juria Toramae on facebook.

Cyrene Reef, Jun 10
Photos shared by Loh Kok Sheng on his flickr.

Cyrene Reef, May 11
Photo shared by Marcus Ng on flickr.

Cyrene Reef, May 11
Photo shared by Marcus Ng on flickr.

Pulau Semakau South, Jul 15
Photo shared by Jianlin Liu on facebook.

Beting Bemban Besar, Jun 21
Photo shared by Richard Kuah on facebook.

With grateful thanks to Ondrej Radosta for identification help with these crabs..



  • 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.
  • 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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