An Update on Novel Taxa and Revised Taxonomic Status of Bacteria (Including Members of the Phylum ) Isolated from Aquatic Host Species Described in 2018 to 2021.

Increased interest in farmed aquatic species, aquatic conservation measures, and microbial metabolic end-product utilization have translated into a need for awareness and recognition of novel microbial species and revisions to bacterial taxonomy. Because this need has largely been unmet, through a 4-year literature review, we present lists of novel and revised bacterial species (including members of the phylum ) derived from aquatic hosts that can serve as a baseline for future biennial summaries of taxonomic revisions in this field. Most new and revised taxa were noted within oxidase-positive and/or nonglucose fermentative Gram-negative bacilli, including members of the , , and genera. Valid and effectively published novel members of the Streptococcus, , and genera are additionally described from disease pathogenesis perspectives.