Glissandra oviformis n. sp.: A novel predatory flagellate illuminates the character evolution within the eukaryotic clade CRuMs

Culturing protists offers a powerful approach to exploring eukaryotic
diversity, especially for deep-branching lineages. In this study, we
cultured and described a novel protist species, named Glissandra oviformis
n sp., within the poorly studied and unclassified genus Glissandra. While
an SSU rDNA gene phylogeny failed to resolve its phylogenetic placement in
the eukaryotic tree, a phylogenomic analysis of 340 proteins indicated G.
oviformis as a deep-branching member of the CRuMs clade. Prior to this
study, this clade consisted of diverse heterotrophic amoeba and
flagellates and lacks clear synapomorphies. Ultrastructural observations
revealed that G. oviformis shares the characteristics with some CRuMs
members, including the pellicle underlying the plasma membrane and an
internal sleeve surrounding the central pair of the axoneme at the
flagellar transitional region. Our findings suggest potential shared
characteristics and synapomorphies for CRuMs and contribute to a deeper
understanding of the character evolution within CRuMs.