Dactylogyrids (Monogenoidea) Parasitizing Microlepidotus brevipinnis (Haemulidae) from the Pacific Coast of Mexico: Magnanchor raris n. gen., n. sp. and Supplementary Taxonomic Information for Mexicana bychowskyi Caballero and Bravo-Hollis 1959

Abstract

As part of a marine ecology study aimed to discover the diversity of fish parasites, we described a new species representing Magnanchor n. gen. and provided new and supplementary morphometric information for Mexicana bychowskyi, both monogenoidean species collected from the gill lamellae of the humpback grunt Microlepidotus brevipinnis (Haemulidae) from the Pacific coast of Mexico. The new genus is proposed for its unique species, M. raris n. sp. which is characterized in having overlapping gonads (testis posterodorsal to the germarium), a copulatory complex consisting of counterclockwise coils of the copulatory organ that is unarticulated to the accessory piece, a haptor armed with two pairs of anchors (each with broad base and well differentiated roots), dorsal and ventral bars, a dextral vaginal aperture, and 6 pairs of hooks with uniform shank and upright acute thumb. Data on morphological and biometric variability of the six species of Mexicana (including illustrations of the haptoral structures of the present specimens of M. bychowskyi) previously described and/or reported parasitizing different haemulid hosts from the Pacific and Atlantic oceans in the Tropics are also provided. Due to the morphological similarities among the amphiamerican species of Mexicana, they could represent sister-species pairs in the Tropics. Magnanchor raris n. sp. and M. bychowskyi (type species of the genus) are the first dactylogyrids described and/or reported on M. brevipinnis.