A Gram-stain-negative, aerobic and non-motile rods strain, designated as strain 2012CJ39-3T, was isolated from a marine sponge, Myxilla rosacea, collected on Chuja Island, Republic of Korea. Optimal growth of strain 2012CJ39-3T was observed at 25 °C, pH 7.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Strain 2012CJ39-3T contained menaquinone-6 as the respiratory quinone, iso-C15 : 1 G, iso-C15 : 0, and iso-C17 : 0 3-OH as the predominant fatty acids, and phosphatidylethanolamine, an unidentified phospholipid, an unidentified glycolipid, three unidentified aminolipids and nine unidentified lipids as major polar lipids. The genomic DNA G+C content was 38.4 mol%. Results of phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain 2012CJ39-3T formed a distinct phyletic lineage in the genus Muricauda. Strain 2012CJ39-3T was most closely related to Flagellimonas hymeniacidonis 176CP5-101T, Muricauda spongiicola 2012CJ35-5T, Muricauda algicola AsT0115T, Muricauda flava DSM 22638T and Muricauda parva SW169T with 96.5, 96.4, 96.3, 95.8 and 95.6 % 16S rRNA gene sequence similarity, respectively. The average nucleotide identity and digital DNA-DNA hybridization values between strain 2012CJ39-3T and M. spongiicola 2012CJ35-5T, F. hymeniacidonis 176CP5-101T, M. algicola AsT0115T, M. flava DSM 22638T and M. parva SW169T were 75.6, 74.2, 78.6, 75.3 and 74.8 % and 27.4, 19.9, 36.3, 24.2 and 18.9 %, respectively. Based on these results, strain 2012CJ39-3T represents a novel species of the genus Muricauda, for which the name Muricauda myxillae sp. nov. is proposed. The type strain is 2012CJ39-3T (=KACC 22644T= LMG 32582T). In addition, Flagellimonas hymeniacidonis is reclassified as Muricauda symbiotica nom. nov.
Keywords: Muricauda myxillae; Muricauda symbiotica; Myxilla rosacea; marine sponge; new taxa.