Hemiurid Trematodes (Digenea: Hemiuridae) from Marine Fishes off the Coast of Rio de Janeiro, Brazil, with Novel Molecular Data

Abstract

Brazil is a tropical country with remarkably diverse marine habitats that harbour a rich diversity of fish. Only a small portion of this fish diversity has been investigated for parasites, and thus the diversity of their trematode parasites remains unexplored. Moreover, only 5 out of 184 known digenean trematode species of marine fish in Brazil have been genetically characterised. The Hemiuridae Looss, 1899 is the second most speciose trematode family in marine fishes from Brazil but, in many ways, it remains a neglected group. Forty-three trematode specimens from nine fish species were collected from the coastal zone off Rio de Janeiro, Brazil. Trematodes were found in the stomach of 14 specimens of 9 fish species belonging to 8 families (Carangidae, Clupeidae, Haemulidae, Muraenidae, Percophidae, Pinguipedidae, Trichiuridae, and Triglidae). Trematode specimens were studied using morphological and molecular genetic analyses. A total of eight hemiurid species from four genera, Ectenurus, Lecithochirium, Myosaccium, and Parahemiurus were identified. This paper reports on new host records for four species of hemiurids, adds a new record on the geographical distribution for one species, and provides the first DNA sequence data supplemented with the detailed description of morphology for five species. Phylogenetic analyses supported that the subfamily classifications of the Hemiuridae—based entirely on morphological characters—needs to be reconsidered, taking into account a wider range of information sources.

Morphological and molecular characterization of Stomachicola muraenesocis Yamaguti, 1934 (Digenea: Hemiuridae) from the daggertooth pike conger Muraenesox cinereus (Forsskål)

“…In the present study, the phylogenetic relationship of the representatives of the superfamily Hemiuroidea was not highly supported in the ML tree based on 28S rDNA dataset. However, the topologies obtained in the ML and BI trees were in general congruent with those obtained in previous studies (Pankov et al ., 2006; Atopkin et al ., 2017; Sokolov et al ., 2019, 2021; Faltýnková et al ., 2022; Pantoja and Kudlai, 2022; Louvard et al ., 2022 b ). As the molecular data of members belonging to genera within the subfamilies Dinurinae/Mecoderinae ( Dinurus , Ectenurus Looss, 1907, Paradinurus Vigueras, 1958, Erilepturus Woolcock, 1935, Qadriana Bilqees, 1971, Allostomachicola , Mecoderus , Stomachicola , Tubulovesicula ) are largely unknown, only a few available sequences with similar length to those of Stomachicola were retrieved from the GenBank and included in phylogenetic analyses in this study.…”

“…Newly generated sequences were aligned with those previously reported for species within the superfamily Hemiuroidea (see Table 2) following the alignments from Louvard et al . (2022 b ) and Pantoja and Kudlai (2022). Sequences of Azygia longa (Leidy, 1851) (Azygioidea: Azygiidae), Proterometra sp.…”