Morphological identification tools of Pseudodiscocotyla opakapaka and Kannaphallus raphidium (Monogenea: Polyopisthocotylea) from Acanthopagrus bifasciatus (Spariformes: Sparidae)

Abstract

Fish is considered one of the nutritive protein sources affected by various parameters including parasitism. Monogeneans are an ectoparasitic species infecting fish’s skin, fins, and gills. During the present investigation, a total of 40 fish samples of the twobar seabream, Acanthopagrus bifasciatus (Perciformes: Sparidae) were collected from the coastal region along the Arabian Gulf (Saudi Arabia). The collected fish samples were dissected and examined for the presence of monogenetic parasites. The recovered parasite species were collected and identified by applying light microscopic examinations. Five out of 40 (12.5%) fish samples were found to be naturally infected with 2 monogenetic species belonging to two families within Polyopisthocotylea (order Mazocraeidea). They recorded two parasite species, namely, Pseudodiscocotyla opakapaka Yamaguti, 1965 and Kannaphallus raphidium Kritsky and Martin, 2023 belonging to families Discocotylidae and Heteraxinidae, respectively. Morphological and morphometric characterizations revealed some differences between the present species and others detected previously. The present findings of P. opakapaka and K. raphidium in A. bifasciatus (fish host) of the Arabian Gulf represent a new host and geographical record for these parasites. Furthermore, more studies are required to include the advanced molecular tools for these monogenetic species and their associated histopathological effects on the infection site.