Content area
Full Text
(ProQuest: ... denotes non-US-ASCII text omitted.)
INTRODUCTION
Uca tangeri (Eydoux, 1835) is a common crab in marsh land, mud flats, often near river mouths, along the west coast of Africa from Morocco to southern Angola. It is also present on the coast of Portugal, but it does not occur in the Mediterranean (Holthuis, 1981; Manning & Holthuis, 1981; Schneider, 1990).
According to Burggren & McMahon (1988), U. tangeri with a maximum carapace length of 33 millimetres (47 mm carapace width) is the largest species in the genus Uca (Holthuis, 1981; Lloris & Rucabado, 1998). The most notable feature of this species is the dimorphism of the chelae. Males have one small chela (smaller than observed in females) and the other is enormously enlarged. The small chela is mainly used for feeding while the large one is used for agonistic and mating displays (Christy & Salmon, 1984; Burggren & McMahon, 1988). The waving and vertical movements of the larger chela, together with quick movements of the small one during feeding, have given the genus its popular name of 'fiddler crabs' (Burggren & McMahon, 1988). Fiddler crabs live in burrows and galleries created into the mud and used for protection during high tide, emerging when galleries are exposed at low tide (Altevogt, 1959; Montague, 1980).
There are no reports of the presence of this crab at Madeira and Cabo Verde archipelagos. However, García-Cabrera (1971), in a paper about similarities of Canary Islands and Antilles marine fauna, reported the presence of U. tangeri in the list of brachyuran species of both areas, but without site specification. Because of this lack of specificity and because there are no previous or later references to that of García-Cabrera in this archipelago González-Pérez (1995) excluded this crab from the species catalogue of crustaceans of the Canary Islands. Also, the citation of U. tangeri for the Antilles...