Three Gram-negative, non-spore-forming strains were isolated from sediment from the South China Sea, China, and their taxonomic positions were investigated using a polyphasic approach. Strains HN-171(T), HN-172 and HN-181 grew optimally at 30 degrees C, in the presence of 4.5-5.0 NaCl % (w/v) and at pH 7.2-7.4. They contained MK-6 as the predominant respiratory quinone and contained iso-C(15 : 1) G, iso-C(15 : 0), summed feature 4 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c/t) and C(15 : 0) as the major fatty acids. The DNA G+C content of strain HN-171(T) was 34.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences demonstrated that strain HN-171(T), together with strains HN-172 and HN-181, formed a distinct evolutionary lineage within the family Flavobacteriaceae. The 16S rRNA gene sequences of strains HN-171(T), HN-172 and HN-181 shared 99.8-100 % similarity with each other, and the sequence of strain HN-171(T) exhibited similarity values below 90.2 % with those of other members of the family Flavobacteriaceae. The closest relative of HN-171(T) was Coenonia anatina LMG 14382(T) (90.2 %). On the basis of their phenotypic and phylogenetic properties, the three isolates represent a novel genus and a novel species, for which the name Zhouia amylolytica gen. nov., sp. nov. is proposed. The type strain is HN-171(T) (=CGMCC 1.6114(T)=JCM 14016(T)).