Taxonomic revision of the Mexican Eucyclops (Copepoda: Cyclopoida) with comments on the biogeography of the genus Author Mercado-Salas, Nancy F. Department of Aquatic Ecology and Systematics, El Colegio de la Frontera Sur (ECOSUR), Chetumal, Quintana Roo, México; Author Suárez-Morales, Eduardo Department of Aquatic Ecology and Systematics, El Colegio de la Frontera Sur (ECOSUR), Chetumal, Quintana Roo, México; Author Silva-Briano, Marcelo Department of Biology, Universidad Autónoma de Aguascalientes, Aguascalientes, México text Journal of Natural History 2015 2015-07-31 50 25 147 http://dx.doi.org/10.1080/00222933.2015.1061715 journal article 21298 10.1080/00222933.2015.1061715 66476c49-1f53-451b-9c02-9fde16197b38 1464-5262 3983088 2F320DE0-FF96-4E5F-8520-586303082E09 Genus Eucyclops Claus, 1893 Shared characters among species Females. Prosome widest at end of cephalosome and second pediger. Urosome fivesegmented, slightly elongated. First urosomal somite with long setules on lateral margin. Posterior margin of anal somite with row of spinules; anal somite as long as preanal somite. Inner margin of caudal rami naked. Terminal setae of caudal ramus plumose. Antennules 12- segmented with finely denticulated hyaline membrane on segments 10 – 12. Third swimming leg with small spinules along insertion of basipodite (frontal surface). Males. More slender than female, with urosome six-segmented. Antennules 16-segmented in examined species.