Molecular (cox1), geographical, and host record investigation of monogeneans Mazocraes australis (Mazocraeidae), Polylabris sillaginae, and P. australiensis (Microcotylidae)

Abstract

This study determines the occurrence and molecular characterisation of Monogenea from three commercially important Australian fish: Australian sardine Sardinops sagax (Jenyns), Australian anchovy Engraulis australis (White), and eastern school whiting Sillago flindersi McKay. Earlier studies have provided only morphological species identification, whereas this study combines both morphological and molecular methods. A total of 247 fish across 3 species, sourced from the New South Wales and Victorian coasts, were examined for Monogenea. A total of 187 monogenean parasites were recovered from the gills. The overall prevalence, mean intensity, and mean abundance were 34%, 2.23, and 0.78, respectively. The parasites were initially classified morphologically as three species across two families. Family Mazocraeidae was represented by Mazocraes australis Timi et al. J Parasitol 85:28–32, 1999, and family Microcotylidae by Polylabris sillaginae (Woolcock, Parasitology 28:79–91, 1936) Dillon, Hargis, and Harrises, 1983 and P. australiensis Hayward, 1996. Molecular identification of parasites was conducted through sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. The fish hosts in the present study were also barcoded (mitochondrial cox1 gene) to confirm specific identities. There was no comparable cox1 sequence available in GenBank for the parasites found in the present study. However, the phylogenetic tree clustered the monogenean species identified in this study according to their familial groups of Mazocraeidae and Microcotylidae. The presence of M. australis on E. australis and S. sagax was confirmed in this study. Polylabris australiensis was only found on S. sagax but Si. flindersi was found to be a host for both Polylabris species. This study is the first to explore the mitochondrial cox1 genes of these three-monogenean species. These findings will serve as a foundation for future monogenean research in Australian waters and elsewhere.

“Something old, something new, something borrowed, and the oioxeny is true”: description of Plectanocotyle jeanloujustinei n. sp. (Polyopisthocotylea, Plectanocotylidae) from the MNHN Helminthology collection with novel molecular and morphological data for P. gurnardi (Van Beneden & Hesse, 1863) (sensu stricto) from Sweden

“…Overall, the presence of Polyopisthocotylea in distinct localities is not unusual and has been previously challenged by cox 1 barcodes. Consequently, the taxonomic and geographic status of several polyopisthocotyleans has been validated (see ( Hossen et al, 2022a , 2022b ). Hossen et al (2022b) demonstrated with cox 1 barcodes the presence of Allogastrocotyle bivaginalis both in Mediterranean waters, off Algeria (report by Bouguerche et al, 2019a , Bouguerche et al, 2019b ) and in Australian waters (Victoria) of the southwest Pacific.…”