A new species of van Beneden, 1892 (Copepoda, Siphonostomatoida, Caligidae) from Aetobatuscf.narinari (Pisces, Myliobatidae) from the Pacific coast of Ecuador.

A new caligid copepod species, is described based on female and male specimens collected from the gills of the myliobatid elasmobranch Aetobatuscf.narinari Euphrasen, 1790 captured off the Pacific coast of Ecuador. The new species has a unique combination of characters that diverges from its known congeners, including: (i) weakly developed posterolateral processes on the genital complex; (ii) large spines on posterior surface of maxilliped basis (iii) abdomen slender, unsegmented, approximately 1/2 length and 1/5 width of genital complex; (iv) third exopodal segment of leg II with single long naked spine adjacent to minute, naked lateral spine; (v) velum of leg II with adjacent patch of denticles; (vi) caudal rami slightly less than half the length of genital complex; (vii) post-antennal process with robust, posteriorly directed tine, sclerotized stump posterolaterally, and two multi-sensillate papillae located on or near base of process (viii) post-oral process oval. The overall prevalence of on its host was 37.5% and its mean abundance was 1.87 specimens per host. This is the second record of the genus from Ecuador and the second record of infecting rays of the Myliobatinae genus , of the subfamily Myliobatinae, after its discovery on in Australia, thus confirming this expansion of its previously known host range to a new elasmobranch subfamily.