A novel Gram-stain-positive, coccus-shaped, obligately anaerobic bacterium was isolated from a faecal sample obtained from an individual in a traditional community located off the southern coast of Peru. Comparative 16S rRNA gene sequence analysis showed the novel bacterium belonged to the genus Peptoniphilus but showed no particular relationship with any species, demonstrating less than 91% 16S rRNA gene sequence similarity with all members of the genus. The major cellular fatty acids of the novel isolate were determined to be C10: 0, C14: 0, C16: 0, C18: 1ω9c and C18: 2ω6,9c/anteiso-C18: 0. The DNA G+C content was 34.4 mol%. End-products of metabolism from peptone-yeast-glucose broth (PYG) were determined to be acetate and butyrate. Based on the phenotypic, chemotaxonomic and phylogenetic results, the organism represents a novel species of the genus Peptoniphilus, for which the name Peptoniphilus catoniae sp. nov. is proposed. The type strain is M6.X2DT (=DSM 29874T=CCUG 66798T).