Antarctic Fish Parasite Confirmed as Distinct Species Through DNA and Morphology

A parasitic flatworm long shuffled between species names has been restored as a distinct species. An integrative study published in Acta Parasitologica supports the validity of Pseudobenedenia lauriei, a capsalid monogenean that parasitizes the Antarctic fish Notothenia neglecta off West Antarctica. The genus Pseudobenedenia includes monogeneans infecting Antarctic nototheniid fishes and has long suffered from taxonomic instability, with P. lauriei often treated as a synonym of P. nototheniae. The new work, based on newly collected material together with comparative examination of museum specimens, aimed to reassess the species’ status using morphology, morphometrics and molecular analyses.

The evidence came from several independent lines. Morphological comparisons identified a consistent set of diagnostic features distinguishing P. lauriei from its congeners. Multivariate statistical analyses, using principal component analysis and Gower distance measures, clearly separated P. lauriei from all other species in the genus. Phylogenetic analyses built on partial 18S and 28S rDNA sequences further supported a distinct position for P. lauriei within the Antarctic clade of Pseudobenedenia, indicating that the worm is not simply a variant of P. nototheniae but a separately evolving lineage.

The study also revisited historical material, and this re-examination suggested that many records previously assigned to P. nototheniae may in fact represent distinct host-associated species. That finding implies the taxonomy of Antarctic capsalids may be more diverse than current checklists indicate, and that host identity, particularly the association with N. neglecta, is an important character for resolving species boundaries within the genus.

The authors emphasize the continued value of museum collections for resolving the taxonomy of Antarctic parasites, since archived specimens allow modern morphological and molecular comparisons with material collected decades ago. The study is an original research article published in Volume 71 of the journal, with the article appearing online on 28 October 2026. As with any taxonomic revision, the conclusions rest on the material examined, and the authors’ reassessment of historical records is presented as a suggestion that prior identifications warrant re-evaluation rather than a definitive recount of every published record.

Subject of Research: Taxonomic reassessment of the Antarctic fish parasite Pseudobenedenia lauriei using morphology and DNA sequences

Article Title: Molecular Characterization of Pseudobenedenia lauriei Szidat, 1965 (Monopisthocotyla: Capsalidae) from Notothenia neglecta Nybelin, 1951, off Antarctica

Article References: Rubtsova, N., Chaudhary, A., Salganskiy, O., & Kuzmina, T. A. (2026). Molecular Characterization of Pseudobenedenia lauriei Szidat, 1965 (Monopisthocotyla: Capsalidae) from Notothenia neglecta Nybelin, 1951, off Antarctica. Acta Parasitologica, 71(6), Article 250. https://doi.org/10.1007/s11686-026-01434-7

Image Credits: AI Generated

DOI: 10.1007/s11686-026-01434-7

Keywords: Pseudobenedenia lauriei, monogeneans, Antarctica, Notothenia neglecta, taxonomy, capsalids, fish parasites, molecular phylogenetics, morphometrics, museum specimens, Molecular, Characterization