Redescription of Lernaeenicus longiventris Wilson, 1917 (Copepoda: Pennellidae) Parasitic on the Pacific Crevalle Jack Caranx caninus (Carangidae) Through Morphological and Molecular Analyses

Purpose The present study deals with a redescription of the copepod Lernaeenicus longiventris Wilson, 1917 (Copepoda: Siphonostomatoida: Pennellidae) found on the Pacific crevalle jack Caranx caninus Gunther, using morphological and molecular analyses. Methods Fish were collected off Mazatlan Port (23 degrees 12 ' N, 106 degrees 26 ' W), in the State of Sinaloa, Mexico (southeastern Gulf of California). The copepods were morphologically analyzed by light microscopy. Sequences of the COI mtDNA gene were generated for the first time for this species. These sequences were compared to COI sequences from six species of Lernaeenicus available in GenBank. Results The specimens of the present study exhibited a cephalosome without apparent lateral processes, which were originally described for L. longiventris. No remarkable differences were observed with previous descriptions regarding appendages and body proportions. The phylogenetic tree based on COI sequences showed that L. longiventris was closer to L. radiatus although with low bootstrap values support in ML tree, both species formed a sister clade of L. sprattae. Conclusions Lernaeenicus longiventris is the unique species of the genus in the Mexican Pacific and the Gulf of California, and also the unique species of Lernaeenicus infecting C. caninus. Molecular data of L. longiventris from host and locality type are required to avoid misidentification of this species.

Automated summary

The present study redescription the copepod Lernaeenicus longiventris and explores its relationship with other species using morphological and molecular analyses. This research is important for the identification and study of the parasite's host specificity.