Collaboration with the research group of Prof. Marli F. Fiore on the description of Oxynema mangrovii

In this study, conducted as a collaboration between my research group and the group of Prof. Marli Fátima Fiore at CENA/USP, we describe Oxynema mangrovii sp. nov., a new filamentous cyanobacterial species isolated from mangrove soil in the Brazilian Atlantic Forest. We applied a polyphasic taxonomic approach integrating morphology, ecology, whole-genome sequencing, phylogenomics, 16S rRNA gene phylogeny, and 16S–23S ITS sequence and secondary structure analyses to demonstrate that strain CENA135 represents a distinct species within the genus Oxynema. Comparative genomic analyses showed that, although closely related to O. aestuarii from Indian mangroves, CENA135 falls below accepted ANI and dDDH thresholds for species delimitation while maintaining clear genus-level affiliation. The genome further revealed genes associated with stress tolerance and adaptation to saline and metal-rich mangrove environments, underscoring ecological specialization. Altogether, this collaborative work formally establishes O. mangrovii sp. nov. and expands genomic and taxonomic knowledge of cyanobacteria from underexplored mangrove ecosystems.