Unraveling the intricate biodiversity of the benthic harpacticoid genus Nannopus (Copepoda, Harpacticoida, Nannopodidae) in Korean waters

Non-destructive genome skimming for aquatic copepods

“…Despite this, copepod species are still a difficult taxonomic group and need to be identified accurately, which is the basic criterion of biodiversity assessment. Cryptic species are frequently encountered from terrestrial to aquatic animals and copepods are no exception (Gomes et al 2015;Pulido-Santacruz et al 2018;Ramos et al 2019;Vakati et al 2019). Since such species are genetically divergent while morphologically homogenous, classical taxonomy underestimates their diversity (Lajus et al 2015;Vakati et al 2019).…”

“…Cryptic species are frequently encountered from terrestrial to aquatic animals and copepods are no exception (Gomes et al 2015;Pulido-Santacruz et al 2018;Ramos et al 2019;Vakati et al 2019). Since such species are genetically divergent while morphologically homogenous, classical taxonomy underestimates their diversity (Lajus et al 2015;Vakati et al 2019). Cryptic taxa are often characterised by allopatric distribution patterns (Dodson et al 2003;Garlitska et al 2012), however, some cryptic taxa among benthic copepods exist sympatrically (Schizas et al 2002;Vakati et al 2019).…”

“…Since such species are genetically divergent while morphologically homogenous, classical taxonomy underestimates their diversity (Lajus et al 2015;Vakati et al 2019). Cryptic taxa are often characterised by allopatric distribution patterns (Dodson et al 2003;Garlitska et al 2012), however, some cryptic taxa among benthic copepods exist sympatrically (Schizas et al 2002;Vakati et al 2019). Although cryptic taxa are morphologically similar, each species may have a different ecological significance, economic value, and interactions with ecosystems (Eisenring et al 2016), thus, it is crucial to identify these species accurately.…”

“…Sometimes the incorrect pairing of sexes can occur among closely related species; for example, N. minutus and N. dimorphicus are morphologically different but could be misidentified by incorrectly pairing their sexes using classical taxonomy alone (Vakati et al 2019). Overall, the underestimation of cryptic taxa, plus the inverse problem of variable species being erroneously split are both highly problematic, and especially so if only traditional taxonomic approaches are followed.…”

“…In the past, specimens have typically been destroyed to extract DNA for molecular analyses and morphological data is thus obtained from different specimens (Di Capua et al 2017;Karanovic et al 2015). However, this approach is not effective when several cryptic taxa live sympatrically (Schizas et al 2002;Vakati et al 2019). In contrast to macrofauna, meiofauna are extremely small (50-1000 μm), so it is difficult to extract genomic DNA (gDNA) from a part of the specimen to obtain genetic and morphological information from the same individual.…”