Parasitic copepods from two species of commercial fishes collected off Iraq, with description of Hatschekia shari n. sp

Redescription of Hatschekia exigua Pearse, 1951 (Copepoda: Hatschekiidae), parasitic on the Squirrelfish Holocentrus adscensionis (Osbeck, 1765) (Actinopterygii: Holocentridae) off Ceará, Northeastern Brazil, with first description of the male

The original description of Hatschekia exigua Pearse, 1951 neglected innumerous features of taxonomic value as well as morphometric data and illustrations. Posteriorly, other author tried to access the type material, but their poor state of preservation compromised a detailed redescription. Since then, this species is in need for new morphological data, mainly from fresh material. In the present work, three specimens of Holocentrus adscensionis from Mucuripe Bay, Fortaleza, State of Ceará, Northeastern Brazil, were parasitized by copepods on their gills. Parasites were fixed and preserved in 80% ethanol and cleared in 85% lactic acid for morphological observations using light microscopy. The females were identified as Hatschekia exigua by the cephalothorax representing about one-fourth of total body length, with lateral margins expanded into lateral lobes, first exopod with basal segment armed with one outer setae and terminal segment with three setae, first endopod with basal segment unarmed and terminal segment with five setae, leg 3 reduced to two setae and leg 4 reduced to single seta. Comparison with the type series revealed morphological differences in trunk and small appendages, which may be related to alterations in the specimens, caused by the mounting methodology and poor preservation. A detailed morphological analysis of the male revealed for the first time that they differ from their closest congeners by having five setae on the last endopodal segment of leg 1, by smooth intercoxal sclerites on legs 1 and 2 and by a proximolateral process on the third segment of antenna. Moreover, this work represents the first report of H. exigua in Brazil and the first hatschekiid copepod found off the coast of Ceará, highlighting that the diversity of Hatschekiidae in this oceanographic region still needs further investigation.

Morphological and mitochondrial approaches of Hatschekia sargi (Copepoda: Hatschekiidae) as a parasite of Epinephelus chlorostigma

Little information is available until now about the copepods infecting different fish species. Therefore, this study aimed to provide light on siphonostomatoids infecting Epinephelus chlorostigma. Twenty fish specimens were taken from the Red Sea coast (Jeddah, Saudi Arabia), and ectoparasitic copepods were investigated. Light microscopy and molecular tools were used to examine copepods isolated from fish. Parasitological indexes were calculated and showed that 60% of the examined fish were infected with a mean intensity of 12 parasite/fish. Morphological examination revealed that this copepod species is characterized by all unique features of the genus Hatschekia with special reference to Hatschekia sargi. The taxonomic position of the recovered species in the Hatschekiidae family within Siphonostomatoida was confirmed using phylogenetic analysis based on partial mitochondrial cytochrome c oxidase subunit I (mt COI) gene sequences. The mt COI gene query revealed that the recovered Hatschekia species is closely related to Hatschekia maculatus (gb| JQ664005.1). This study discovers a new host for Hatschekia species isolated from Saudi Arabia and conducts the first genomic investigation of the mt COI gene.

A New Species of Hatschekiid Copepod (Crustacea: Hatschekiidae) Parasitic on the Porkfish Anisotremus virginicus (Linnaeus, 1758) (Actinopterygii: Haemulidae), with Notes on Previously Known Species of Hatschekia Poche, 1902 Collected from Actinopterygians off Brazil

INTRODUCTION

Copepods of the genus Hatschekia Poche, 1902 are parasitic on the gills of marine actinopterygians. Currently, about 151 species of this genus have been reported in marine ecosystems and only few occur in South Atlantic Ocean.

METHODS

Fifty specimens of A. virginicus from Angra dos Reis, off the State of Rio de Janeiro, Brazil, were parasitized by copepods on the gills. Parasites were fixed and preserved in 70% ethanol. Morphological observations were based on light and scanning electron microscopy.

RESULTS

Hatschekia nagasawai n. sp. can be distinguished from all congeners by the combination of the following characters: (1) presence of two pointed processes on the proximal (first) segment of antennule, (2) cephalothorax octagonal to ovoid, (3) absence of processes on the intercoxal sclerite of legs 1 and 2, (4) trunk without lobes at the postero-lateral margins. Other species of Hatschekia and their hosts previously collected off Brazil were analysed and discussed.

CONCLUSIONS

This is the first report of a representative of the family Hatschekiidae Kabata, 1979 parasitizing a species of Anisotremus. The number of species of Hatschekia reported in the South Atlantic Ocean was increased to five, including the new species; however, the diversity of hatschekiid copepods in this oceanographic region is still underestimated, most likely being higher than what is currently known.