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A genealogical concordance approach was used to delineate strains isolated from Acacia dealbata and Acacia mearnsii root nodules in South Africa. These isolates form part of Bradyrhizobium based on 16S rRNA sequence similarity. Phylogenetic analysis of six housekeeping genes (atpD, dnaK, glnII, gyrB, recA and rpoB) confirmed that these isolates represent a novel species, while pairwise average nucleotide identity (ANIb) calculations with the closest type strains (B. cosmicum 58S1 T , B. betae PL7HG1 T , B. ganzhouense CCBAU 51670  T , B. cytisi CTAW11 T and B. rifense CTAW71 T ) resulted in values well below 95-96%. We further performed phenotypic tests which revealed that there are high levels of intraspecies variation, while an additional analysis of the nodA and nifD loci indicated that the symbiotic loci of the strains are closely related to those of Bradyrhizobium isolates with an Australian origin. Strain 14AB T (=LMG 31415  T  = SARCC-753  T ) is designated as the type strain of the novel species for which we propose the name Bradyrhizobium xenonodulans sp. nov., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)