New species of continental cyclopoid copepods (Crustacea, Cyclopoida) fromthe Yucatan peninsula, Mexico

We report here on the cyclopoid copepod fauna encountered during a sampling campaign in several community wells on the Yucatan peninsula in 1997. In 1 8 freshwater and oligohaline localities, 13 different cyclopoid species wer e identified. Acanthocyclops rebecae n. sp., found in the south of Campeche , shows clear affinities with the northern vernalis-robustus cline. Two new Diacyclops species, D. pilosus n. sp. and D. ecabensis n. sp. are describe d from wells near the archeological site of Tulum. Both are closely related to D. uruguayensis Kiefer, 1935 and D. hispidus Reid, 1988. Specimens of b oth sexes of Mesocyclops aequatorialis pescei Pesce, 1985 were collected in a deep community water well in the north of Quintana Roo. The male of this species is described for the first time. Micromorphology of the appendages revealed that this subspecies is distinctly different from all other Mesoc yclops species known thus far and should be raised to specific rank. The de scription of Microcyclops echinatus n. sp. which seems closely related to M . elongatus (Lowndes, 1934), is based on specimens obtained in a plankton s ample from Laguna Esmeralda in the center of the peninsula. Finally, some o bservations on two local populations of Microcylops dubitabilis Kiefer, 193 4 are given.