Morphological and preliminary molecular characterization of two indigenous Brachionus species (Rotifera: Monogononta) from a brackish coastal lagoon in Korea

This is the authors' abstract. We don't add key points for this paper.

Brackish water ecosystems form unique ecological structures in which aquatic organisms of both freshwater and marine origin coexist, resulting in high levels of biodiversity distinct from those of typical freshwater or marine systems. However, the biodiversity and accurate taxonomic identification of microfauna within these ecosystems remain poorly understood. In this study, two rotifer strains collected from Hwajinpo Lagoon, a coastal lagoon along the eastern coast of Korea, were investigated using a single isolation-based culture approach for species identification. Based on morphological analyses, the collected rotifers were assigned to the class Monogononta and the genus Brachionus. Notably, these strains exhibited morphological characteristics distinct from those of Brachionus plicatilis and Brachionus rotundiformis, which are commonly reported inhabitants of brackish environments, suggesting potential taxonomic differentiation from previously described species. Furthermore, polymerase chain reaction (PCR)-based molecular evidence provided additional support for the observed taxonomic differentiation. These findings suggest that the rotifer strains examined in this study may represent potentially distinct indigenous lineages and demonstrate their potential as indigenous biological resources for aquaculture and research applications.