Revealing novelty from the southwestern Atlantic, Yemanjia gen. nov. and Olokunococcus gen. nov. from the coral cyanobiome of the Abrolhos Bank.

Cyanobacteria comprise over 6000 species and inhabit diverse environments, including marine invertebrates such as sponges and corals. High-throughput sequencing has indicated an abundance of Cyanobacteria communities in these hosts, yet taxonomic resolution has remained low below the phylum level. Most cultured Cyanobacteria from corals have been isolated from black band disease lesions. However, many other associated taxa remain unidentified, such as the Cyanobacteria detected with microscopy and isotopic studies near coral symbiosomes. Recently, a polyphasic approach revealed six new genera from sponges. Following a similar strategy-integrating molecular phylogeny, morphology, ecology, and chemotaxonomy-we describe two novel genera and three new species of Cyanobacteria from reef-building corals of the Abrolhos Banks (southwestern Atlantic). Two filamentous strains were assigned to the new genus Yemanjia (Cymatolegaceae), closely related to the genus Rhodoploca. A third coccoid strain was assigned to the new genus Olokunococcus (Aegeococcaceae), phylogenetically related to Aegeococcus. All isolates presented phycoerythrins. The closest formally described relatives of these new taxa are all sponge-associated, suggesting an evolutionary and ecological link between host and Cyanobacterial lineage. By providing formal taxonomic anchors for coral-associated Cyanobacteria, our results expand the current knowledge of the coral cyanobiome and facilitate the interpretation of existing and future coral microbiome datasets.