Morphological analysis of Caligus elongatus von Nordmann, 1832 (Copepoda: Caligidae) from the rosy goatfish Parupeneus rubescens (Mullidae)

Copepods are a common component of ectoparasite assemblages of all kinds of fish, from all environments and ecosystems. In the present investigation, a total of 80 specimens of the rosy goatfish Parupeneus rubescens were randomly collected from the Arabian Gulf, and then transported to the laboratory in order to be dissected and examined for the presence of copepodid infections. Copepod parasites were recovered from the gills of the infected fish. One copepod species within the Caligidae family was identified and labeled as Caligus elongates von Nordmann, 1832. This copepod species examined using light and scanning electron microscopy to observe the most characteristic generic features. Morphological and morphometric characterizations revealed differences between the identified species and other related copepodid species. Therefore, the present study showed that the rosy goatfish is a new host for this Caligus species and added a new locality record for this infection. The present study provides that: New data about the natural prevalence of copepods on marine fish. The systematic status of copepodid species, referred to Caligus elongatus. The first record of rosy goatfish as host species for this copepodid species.