A taxonomic study was carried out on strain HYC-10T,which was isolated from the intestinal tract contents of a flathead mullet,Mugilcephalus,captured from the sea off Xiamen Island,China.The bacterium was observed to be Gram positive,oxidase and catalase positive,rod shaped,and motile by subpolar flagella.The bacteriumwas found to grow at salinities of 0-12%and at temperatures of 8-45℃.The isolate was found to hydrolyze aesculin and gelatin,but was unable to reduce nitrate to nitrite.Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HYC-10T belongs to the genus Bacillus,with highest sequence similarity (99.3%) to Bacillus aerophilus 28KT,Bacillus stratosphericus 41KF2aT,and Bacillus altitudinisDSM 21631T,followed by Bacillus safensis DSM 19292T (99.5%) and Bacillus pumilus DSM 27T (99.5%),while the sequence similarities to others were all below 97.6%.The genomicANIm valuesbetween strain HYC-10T and three type strains (B.altitudinis DSM 21631T,B.safensis DSM 19292T and B.pumilus DSM 27T) were determined to range from 89.11%to 91.53%.The DNA-DNA hybridization estimate value sbetween strain HYC-10T and the three type strains were from 36.60%to 44.00%.The principal fatty acids identified were iso-C15:0 (39.1%),anteiso-C15:0 (22.7%),iso-C17:0 (13.1%),C16:0 (6.1%),anteiso-C17:0 (5.8%) and iso-C16:0(5.1%).The G+C content of the chromosomal DNA was determined from the draft genome sequence to be 41.3mol%.The respiratory quinone was determined to be MK-7 (100%).Phosphatidylglycerol,diphosphatidylglycerol,aminoglycolipid,two glycolipids and two unknown phospholipids were found to be present.The combined genotypic and phenotypic data show that strain HYC-10T represents a novel species of the genus Bacillus,for which the name Bacillus xiamenensissp.nov.is proposed,with the type strain HYC-10T (=CGMCC NO.1.12326T = LMG 27143T=MCCC 1A00008T).