A field guide to Kenyan mangroves


Uca chlorophthalmus H. Milne Edwards, 1837

Family: Ocypodidae

Zone: Equally in Rhizophora mucronata, Ceriops tagal and mixed zones (Hartnoll, 1975; Gillikin, 2000).

Habitat: Burrowing to about 50 cm depth.

Food: Detritus (Icely and Jones, 1978).

copulating crabs

Ecological notes: Least heat tolerant of Kenyan Uca (Edney, 1965), therefore in shaded areas. Prefers areas lower on the shore, with moderate organic matter (Gillikin, 2000).

Distinguishing characteristics: Claw bright red or orange; broad front; moderate tuberculate ridge on palm and a triangular depression at the external base of the immobile finger (often filled with mud, a very distinguishing characteristic; seen as dark spot on photo just above water line) (carapace width about 1.5 cm)

Geographical range: Somalia to South Africa; Mauritius and Madagascar (Vannini and Valmori, 1981)


Cannicci, S., F. Dahdouh-Guebas and L. Montemagno, 1993. "Field Keys for Kenyan Mangrove Crabs." Museo Zoologico "La Specola", Dipartimento di Biologia Animale e Genetica dell'UniversitÓ Degli Studi di Firenze, Via Romana 17, I-50125 Firenze, Italia.

Edney, E.B., 1961. "The water and heat relationships of fiddler crabs (Uca spp.)." Trans. roy. Soc. Afr. Vol. XXXVI, part 2, March 1961, p71-91.

Gillikin, D.P., 2000. Factors controlling the distribution of Kenyan brachyuran mangrove crabs: Salinity tolerance and ecophysiology of two Kenyan Neosarmatium species. M.Sc. Thesis, Free University of Brussels, Brussels, Belgium.

Hartnoll, R.G., 1975. "The Grapsidae and Ocypodidae (Decapoda: Brachyura) of Tanzania." J. Zool. Lond. 177:305-328.

Icely, JD and DA Jones, 1978. Factors affecting the distribution of the genus Uca (Crustacea: Ocypodidae) on an East African Shore." Estuarine and Coastal Marine Science 6:315-325.

Macnae, W., 1968. "A General Account of the Fauna and Flora of Mangrove Swamps and Forests in the Indo-West-Pacific Region." Advanced Marine Biology 6:73-270.

Vannini, M. and P. Valmori, 1981. Researchers on the coast of Somalia. The shore and the dune of Sar Uanle. 31. Ocypodidae and Gecarcinidae (Crustacea Brachyura). Monitore Zoologico Italiano 14: 199-226.

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all text and photographs copyrightę 2002-2016 David Gillikin and Anouk Verheyden
Created 28 August 2001

Updated June 24, 2016