Giant spotted hermit crab

IDENTIFYING FEATURES

This species is readily identified by its red-to-orange colour and numerous black-ringed white spots. The body and legs are covered with long tufts of reddish bristles. The left nipper is larger than the right. They have red-and-black eyestalks.

Scientific Name: Dardanus megistos
Common Name: Giant spotted hermit crab
Phylum: Arthropoda Sub-phylum: Crustacea
Size: Up to 25cm but usually 10cm – one of the largest hermit crab species

DISTRIBUTION

Widespread in the Western Indian Ocean, extending from Madagascar and East Africa to northern KwaZulu-Natal.

HABITAT

Shallow underwater reefs and sandbanks. They live in gastropod shells, which provide them with protection and a safe place for the female to keep her eggs.

DIET

They are mostly scavengers but are also known to predate on molluscs, breaking open the mollusc shells with their powerful jaws.

REPRODUCTION

The male hermit crab actively tracks a sexually receptive female using chemo-sensory cues. After encountering a female, he holds onto the aperture of her shell with his minor cheliped and will drag her with him for several days until she is ready to spawn. They copulate partly extended from their shells, they intertwine their walking legs and the male positions his gonopores against hers for transfer of the spermatophores. The fertilized eggs are held against her abdomen under the protection of the gastropod shell. The female carries the eggs for about a month before releasing them.

CONSERVATION STATUS

Unevaluated

SOURCES

Branch, G.M, Branch, M.L, Griffiths, C.L, Beckley, L.E, 1994. Two Oceans: A Guide to the Marine Life of Southern Africa. Struik Nature, Cape Town. 456 pp.
Debelius, H.  2001. Crustacea Guide of the World.  IKAN-Unterwasserarchiv, Frankfurt. 321 pp.
Debelius, H.  2013. Indian Ocean Reef Guide.  Conch Books, Harxheim. 321 pp.
King, D, Fraser, F.  2014. The Reef Guide. Struik Nature, Cape Town. 360 pp.
Encyclopaedia of Life [2014]  http://eol.org/
Great Barrier Reef Invertebrates [2014]  www.gbri.org.au/

 

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