A novel Gram-negative strain WQ 585T, isolated from the faeces of mandrills (Mandrillus sphinx) collected at Yunnan Wild Animal Park, Yunnan province, China, was subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolate belongs to the genus Advenella, sharing 98.5% and 98.2% sequence similarity with the type strain Advenella alkanexedens LAM0050T and Advenella faeciporci M-07T, respectively. The predominant ubiquinone was Q-8. The major cellular fatty acids (> 10%) were C16:0, C17:0cyclo and Summed Feature 2. The G + C content of the genomic DNA of strain WQ 585T was 49.0%. The whole genome average nucleotide identity (gANI) values of strain WQ 585T with strain A. alkanexedens LAM0050T and A. faeciporci M-07T were 86.7% and 86.7%, and the digital DNA-DNA hybridization values of strain WQ 585T with strain A. alkanexedens LAM0050T and A. faeciporci M-07T were 64.5% and 62.5%, respectively. Growth occurred at 10-45°C (optimally at 20-30°C), pH 6.0-9.0 (optimally at pH 7.0), and 0-5% (w/v) NaCl (optimally at 0.5-2.0%). On the basis of the taxonomic evidence, a novel species, Advenella mandrilli sp. nov., is proposed. The type strain is WQ 585T (= KCTC 82396T = CCTCC AA 2020028T).