Abstract

DOMINGUEZ ALONSO, Patricio. A new fiddler crab (genus Uca, Ocypodidae,) from the Plio-Pleistocene from the pacific coast of Honduras. Ameghiniana [online]. 2008, vol.45, n.4, pp.663-676. ISSN 1851-8044.

The first fossils crabs from Honduras assigned to Uca Leach, 1814 (Brachyura, Ocypodidae) taken at Cedeño (Choluteca region) on the Pacific slope around the Gulf of Fonseca are described. Although Uca are common estuarine crustaceans with ~100 extant species across the globe, their fossil record is extremely scarce with only five described taxa. Moreover, these descriptions are based on very fragmentary fossils with poor diagnostic features. On the basis of fourteen silicified specimens, Uca (Uca) marinae sp. nov. is described here. With a large, flattened major cheliped, the new species is most likely related to the extant species Uca ornata, U. maracoani and U. insignis. Farther analysis indicates that the phylogenetic positions of both the new species as well as U. antiqua (Miocene, Northern Brazil) are relatively close to U. ornata. Biogeographic, ethologic, and ecologic interpretations imply that the last common ancestor for the extant forms, Uca ornata, U. maraconai and U. insignis, and the extinct congeners, U. marinae and U. antique, had a Pan-American distribution prior to the early Miocene and experienced at least two vicariance events. The most recent probably occurred after the closing of the trans-Panamanian seaway during the Plio-Pleistocene separating U. insignis and U. maracoani. During an earlier era, another event created a lineage stemming from an ancestor of U. ornata.

Keywords : Uca; Decapoda; Pliocene; Pleistocene; Gulf of Fonseca; Honduras; Central America.