Gram-negative, motile, rod-shaped bacterial strains (designated 4F2 and Kf) were isolated from decaying tissues of various deciduous tree species. Phylogenetic analyses based on their 16S rRNA gene sequences showed that the novel isolates belong to the genus and showed highest (98.3 %) sequence similarity to . Isolate 4F2 formed a separate branch on the phylogenetic tree based on concatenated sequences of four housekeeping genes or whole genome sequences, clearly separate from , suggesting that novel isolates should belong to a novel species. Orthologous average nucleotide identity scores and DNA-DNA hybridization values between isolate 4F2 and type strains of other species in the genus were less than 85 and 30 %, respectively, significantly lower than the species boundary cut-off values (95 and 70 %). A negative reaction for β-galactosidase, the ability to use dextrin and maltose as carbon sources, and an inability to use lactose are the main phenotypic characteristics that can be used to differentiate the novel isolates from . Based on phenotypic and genotypic characteristics, isolates 4F2 and Kf belong to a novel species of the genus , for which the name sp. nov. is proposed. The type strain is 4F2 (=NCAIM B 02661 =LMG 32183 ).