Two Gram-negative, non-fermentative, non-denitrifying, non-pigmented, rod-shaped bacteria that were motile by means of polar flagella, designated strains KMM 330^T and KMM 331, were isolated from a deep-sea sponge specimen and subjected to a polyphasic taxonomic study. The new isolates exhibited 16S rRNA gene sequence similarity of 99·9 %, and their mean level of DNA–DNA relatedness was 82 %. Phylogenetic analysis based on their 16S rRNA gene sequences placed the strains within the genus Pseudomonas as an independent deep clade. Strain KMM 330^T shared highest sequence similarity (96·3 %) with each of Pseudomonas fulva NRIC 0180^T, Pseudomonas parafulva AJ 2129^T and Pseudomonas luteola IAM 13000^T; sequence similarity to other recognized species of the genus Pseudomonas was below 95·7 %. The marine sponge isolates KMM 330^T and KMM 331 could be distinguished from the other recognized Pseudomonas species based on a unique combination of their phenotypic characteristics, including growth in 8 or 10 % NaCl, the absence of pigments, the inability to denitrify and lack of carbohydrate utilization. On the basis of phylogenetic analysis, physiological and biochemical characterization, strains KMM 330^T and KMM 331 should be classified as a novel species of the genus Pseudomonas, for which the name Pseudomonas pachastrellae sp. nov. is proposed. The type strain is KMM 330^T (=JCM 12285^T=NRIC 0583^T=CCUG 46540^T).

An aerobic, Gram-negative bacterium, strain KMM 329T, was isolated from a deep-sea sponge specimen from the Philippine Sea and subjected to a polyphasic taxonomic investigation. Comparative 16S rRNA gene sequence analysis showed that strain KMM 329T clustered with the species of the genus Lysobacter. The highest level of 16S rRNA gene sequence similarity (97.0 %) was found with respect to Lysobacter concretionis KCTC 12205T; lower values (96.4–95.2 %) were obtained with respect to the other recognized Lysobacter species. The value for DNA–DNA relatedness between strain KMM 329T and L. concretionis KCTC 12205T was 47 %. Branched fatty acids 16 : 0 iso, 15 : 0 iso, 11 : 0 iso 3-OH and 17 : 1 iso were found to be predominant. Strain KMM 329T had a DNA G+C content of 69.0 mol%. On the basis of the phenotypic, chemotaxonomic, DNA–DNA hybridization and phylogenetic data, strain KMM 329T represents a novel species of the genus Lysobacter, for which the name Lysobacter spongiicola sp. nov. is proposed. The type strain is KMM 329T (=NRIC 0728T =JCM 14760T).

An aerobic, Gram-negative, yellow-pigmented, non-motile bacterium, designated strain KMM 3882^T, was isolated from a marine bivalve (Anadara broughtoni) collected from Peter the Great Bay, Sea of Japan, and was subjected to phenotypic and phylogenetic analyses. Strain KMM 3882^Twas found to exert a remarkable inhibitory activity against a number of Gram-positive micro-organisms. Phylogenetic analysis based on 16S rRNA gene sequences placed strain KMM 3882^Twithin the genusSphingomonas, as an independent lineage adjacent toSphingomonas dokdonensisDS-4^TandSphingomonas panniDSM 15761^T. Strain KMM 3882^Tshowed the highest 16S rRNA gene sequence similarity toSphingomonas dokdonensisDS-4^T(97.3 %); similarities of 96.5–96.7 % were obtained withSphingomonas pituitosaDSM 13101^T,Sphingomonas azotifigensNBRC 15497^T,Sphingomonas asaccharolyticaNBRC 15499^T,Sphingomonas trueperiDSM 7225^TandSphingomonas panniDSM 15761^T. Chemotaxonomically, strain KMM 3882^Tcontained sphingoglycolipid, C_16 : 0and C_18 : 1as predominant fatty acids and 2-OH C_14 : 0as a major 2-hydroxy fatty acid, confirming the affiliation of strain KMM 3882^Twith the genusSphingomonas. On the basis of phylogenetic analysis, DNA–DNA hybridization and physiological and biochemical characterization, strain KMM 3882^Tshould be classified as representing a novel species of the genusSphingomonas, for which the nameSphingomonas molluscorumsp. nov. is proposed. The type strain is KMM 3882^T(=An 18^T=NRIC 0685^T=JCM 14122^T=CIP 109223^T).

An aerobic, Gram-negative, motile, non-pigmented bacterium, strain KMM 3042T, isolated from a deep-sea brittle star in the Fiji Sea, was subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequences revealed marine Mn(II)-oxidizing isolate S185-2B as the closest neighbour of strain KMM 3042T (99.9 % sequence similarity). The two strains formed a distinct lineage within the genus Pseudomonas adjacent to the members of the Pseudomonas borbori cluster, sharing highest sequence similarity of 97.4 and 97.0 %, respectively, with P. borbori DSM 17834T and Pseudomonas flavescens DSM 12071T. The DNA–DNA hybridization value (71 %) between strains KMM 3042T and S185-2B confirmed their assignment to the same species. On the basis of phylogenetic analysis, DNA–DNA hybridization and physiological and biochemical characterization, strains KMM 3042T and S185-2B should be assigned to a novel species of the genus Pseudomonas, for which the name Pseudomonas marincola sp. nov. is proposed. The type strain is KMM 3042T (=NRIC 0729T =JCM 14761T).