Parasitic isopods (Crustacea: Dajidae) of euphausiids (Crustacea: Euphausiacea) in the western Caribbean Sea

Abstract

ABSTRACT In this work, we provide new data on the parasitic isopods infecting euphausiid species in the western Caribbean Sea, Northwestern Tropical Atlantic (NWTA). Our study was based on the examination of a total of 211 zooplankton samples obtained in 1999, 2010 and 2011 from the western Caribbean Sea (i.e. the eastern coast of the Yucatan Peninsula, off the southwest coast of Cuba and Honduras) with different sampling gears at a depth range of 0–200 m. Euphausiid species were examined to detect parasitic isopods. Three species of these parasites were identified. One of them, Heterophryxus appendiculatus G. O. Sars, 1885 has been hitherto reported exclusively as a parasite of the species of Euphausia Dana, 1852; quite unexpectedly, this species was found as a parasite of Thysanopoda aequalis Hansen, 1905, thus expanding its known host range to a different euphausiid genus. We also report the finding of two specimens of Oculophryxus bicaulis Shields and Gómez-Gutiérrez, 1996, only known as a parasite of Stylocheiron G. O. Sars, 1883. Accordingly, O. bicaulis was observed on S. affine G. O. Sars, 1883 in the western Caribbean. The third isopod species herein reported is the rare Branchiophryxus koehleri Nierstrasz & Brender à Brandis, 1931. We found only one female individual of this species attached to S. longicorne. Members of this dajid genus have been recorded only a few times and this is the first record in the NWTA. We report a new host record at the genus level of Heterophryxus appendiculatus. Oculophryxus bicaulis was confirmed as a parasite of Stylocheiron species. The rare Branchiophryxus koehleri was first recorded for the NWTA region. We presume that some of these isopods indeed have a wide distribution in tropical and subtropical areas but tend to be overlooked in routine examination of zooplankton samples.