Morphology, taxonomy and epitypification of Eaprasiola yunnanica (C.-C.-Jao) comb. nov. (Prasiolaceae, Trebouxiophyceae) from China using reverse and integrative approaches

The <i>Prasiola</i>-like Prasiolaceae includes some 35 species of monostromatic green algae found in a wide range of habitats, including marine, freshwater, and terrestrial environments, across polar, cold, temperate, and subtropical regions. They exhibit considerable phenotypic plasticity, complicating identification based on morphology alone. Here, we used a approach based on full-length 18S rDNA amplicon sequencing to identify <i>Prasiola</i>-like specimens from China. Amplicon sequence variants (ASV) belonging to Prasiolaceae were detected in material collected at W'umonshan, Yunnan Province, China, and living specimens were subsequently collected from the corresponding sampling locations. We here designate a sequenced specimen as epitype as the holotype of P<i>rasiola yunnanica</i> C.-C. Jao is a formaldehyde-fixed specimen that cannot be sequenced. By combining molecular phylogenetics and morphological observations, we provide a comprehensive assessment of three <i>Prasiola</i>-like collections, identified through integrative taxonomy, as <i>Eaprasiola yunnanica</i> (C.-C.-Jao) <i>comb. nov.</i>, a species distinct from<i> Eaprasiola japonica</i> (Yatabe) Heesch, Guiry <i>et</i> Rindi from Japan. This finding highlights the effectiveness of the reverse taxonomy approach in detecting rare algae, and emphasizes the importance of integrative methods for achieving a thorough and accurate assessment of algal taxonomy and diversity.