Description of two new species of Ridgewayia (copepoda: calanoida) from anchialine caves in the galapagos archipelago

Two new calanoid copepods, Ridgewayia delfine sp. nov. and Ridgewayia tunela sp. nov., are described from anchialine caves in the Galapagos Archipelago. Details of the female genital segment and the female and male fifth legs help distinguish these species from each other and from other members of the same genus. The two new species belong to the Ridgwayia marki species-group, which are found predominantly in the Caribbean with one member in the Mediterranean and one in the Indo-West Pacific. These are the first species of Ridgewayia described from the Eastern Pacific. The volcanic origin of the Galapagos necessitates the dispersal of these ridgewayiids to the islands from other regions. It is currently thought that Ric gewayia is a relict from the Tethyan Sea and that members of the nial-ki-species group crossed from the Caribbean into the Pacific during the circurntropical existence of this sea. The possibility remains that this crossover and colonization of the Galapagos occurred more recently while the Panama seaway remained open. It is clear that the current knowledge of the ridgewayiids is insufficient for a definitive conclusion. Further exploration is necessary to generate an exhaustive list of species of Ridgewayidae and their distribution.