A novel, Gram-negative, non-spore-forming, pleomorphic yellow-orange bacterial strain was isolated from a stadium seat. Strain Coronado(T) falls within the Erythrobacteraceae family based on 16S rRNA phylogenetic analysis, but is both phylogenetically and physiologically distinct from existing genera in the family. A phylogenetic tree inferred from 16S rRNA gene sequences shows a highly supported clade containing Coronado(T), Porphyrobacter, Erythromicrobium, and Erythrobacter. While this strain has Q-10 as the predominant respiratory lipoquinone, as do other members of the family, the fatty acid profile of this strain is distinct. Coronado(T) contains predominatly C18:1ω7cis and C16:0, a high percentage of the latter not being observed in any other Erythrobacteraceae. This strain is catalase-positive and oxidase-negative, the latter of which is unusual for the other genera present in the same clade. Coronado(T) can grow from 4-28°C, at NaCl concentrations 0.1-1.5%, and at pH 6.0-8.0. On the basis of phenotypic and phylogenetic data presented in this study, strain Coronado(T) represents a novel species in a new genus in the family Erythrobacteraceae for which the name Kirrobacter mercurialis gen. nov., sp. nov. is proposed; the type strain is Coronado(T) (=DSMZ 29971, =LMG 28700).