Neglectella glomerata sp. nov., a new species and implications for the systematics of the genus Neglectella (Oocystaceae, Trebouxiophyceae, Chlorophyta)

The genus Neglectella Vodenicarov & Benderliev has a morphology similar to the well-known genus Oocystis , except for the numerous chloroplasts stacked in the surface layer of the cell. Neglectella subsequently experienced complex taxonomy changes with members being transferred in and out, and five species are now accepted. In this study, a new alga with morphology corresponding to this genus was collected in China and successfully cultured in laboratory. Morphological observations in light microscopy and transmission electronic microscopy (TEM) and phylogenetic analyses revealed that it is a new species, described here as Neglectella glomerata sp. nov. It differed from other Neglectella species due to a morphological difference in its unique mucilaginous colony with a large number of cells, multiple pyrenoids in each chloroplast, smaller cell size, and more elongated cell shape. Phylogenetic analyses placed this alga in the subfamily Eremosphaeroideae of the family Oocystaceae and showed its close relationship with Neglectella peisonis . Further morphological comparisons combined with phylogenetic results revealed three different morphological types in Neglectella. The new type represented by our new species may represent a transitional morphology in intermediate taxonomic position between the other two types. The diversity of morphological types in Neglectella suggests that further unknown species of this genus are likely to be discovered in the future. More collections and DNA sequence data will be needed in the future for this genus.