Linking adults and cystacanths of a new species of Rhadinorhynchus Lühe, 1911 (Acanthocephala: Rhadinorhynchidae) from the Pacific coast of Mexico by using morphological and molecular data.

During parasitological surveys of marine fishes and zooplankton in localities of the Northwestern Pacific coast of Mexico, 28 Gafftopsail pompano (Trachinotus rhodopus Gill) and 50 mysid crustaceans (Metamysidopsis frankfiersi Hendrickx & Hernández-Payán) we identified to be infected with adults and cystacanths, respectively of an acanthocephalan morphologically corresponding to the genus Rhadinorhynchus Lühe, 1911. DNA sequences of the small (SSU) and large (LSU) subunits of ribosomal DNA, and cytochrome c oxidase subunit 1 (cox 1) from mitochondrial DNA were obtained. Phylogenetic analyses revealed that the newly sequenced individuals in a clade with Rhadinorhynchus sp.

Amblyopsoides ohlinii (W.M. Tattersall, 1951) (Peracarida, Mysida, Mysidae) in western Mexico.

The rare pelagic mysid Amblyopsoides ohlinii (W.M. Tattersall, 1951) is reported for the first time off western Mexico and represents the first record in the Pacific Ocean south of Japan and the Kurile-Kamchatka Trench.

Rediscovery of Hansenomysis lucifugus (Faxon, 1893) (Crustacea, Mysida, Petalophthalmidae) in the eastern Pacific.

The deep-water mysid, Hansenomysis lucifugus (Faxon, 1893), previously known only from the type locality off the Galapagos Islands, is rediscovered off western Mexico. A complete description is provided based on this new material. The new records correspond to a series of 15 adult females and increase the known distribution of this species by over 30° of latitude to the north, to 30°51.