Lepeophtheirus mondacola sp. nov. (Copepoda; Caligidae) parasitic on the shortjaw leatherjacket Oligoplites refulgens (Teleostei; Carangidae) in the Gulf of California, Mexico.

A new species of parasitic copepod, Lepeophtheirus mondacola sp. nov. (Siphonostomatoida; Caligidae), is described based on female and male specimens obtained from the shortjaw leatherjacket Oligoplites refulgens (Actinopterygii; Perciformes; Carangidae), captured in the southeastern Gulf of California off northwestern Mexico. The new species can be separated from its congeners by a combination of characters that includes: adult female with a subquadrate genital complex bearing slightly protruded posterolateral corners, two indistinct somites on the abdomen which, when combined together, is about two times longer than wide, a caudal ramus that is twice as long as it is wide, a postantennal process comprising a stout base and short claw, a dentiform process of the maxillule with two unequal tines, a maxilliped with a stout protopod and subchela, a sternal furca with a pair of bifurcated tines, a leg 3 exopod composed of 2 segments, five setae on the distal endopodal segment of leg 3 and a leg 4 exopod composed of three segments and armed with one long and two short apical spines on the distal exopodal segment; adult male with a suborbicular genital complex, an abdomen composed of one short and one long, indistinctly separated somites, a caudal ramus that is twice as long as it is wide, a stout postantennal process, a small triangular process at the base of the inner tine of the maxillulary dentiform process and a 3-segmented exopod on leg 4. Lepeophtheirus mondacola sp. nov. represents the first record of a species of Lepeophtheirus from a member of Oligoplites and the second caligid species reported from O. refulgens.