Paracrocinitomix mangrovi gen. nov., sp. nov., isolated from a mangrove sediment: proposal of two new families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov., and emended description of the family Schleiferiaceae.

A Gram-stain-negative and short rod-shaped bacterial strain designated GM2-3-6-6 was obtained from a mangrove sediment. Cells were light yellow-pigmented, catalase-positive and oxidase-positive. Carotenoid pigment was produced. Phylogeny of the 16S rRNA gene showed that strain GM2-3-6-6 was affiliated to the family Crocinitomicaceae, sharing maximum sequence similarities with Crocinitomix algicola 0182, C. catalasitica IFO 15977, and Putridiphycobacter roseus SM1701 of 93.8%, 93.6%, and 92.5%, respectively. The average nucleotide identity values, digital DNA-DNA hybridization estimates and average amino acid identity values between strain GM2-3-6-6 and the three close relatives were 68.6-68.8%, 18.5-19.2%, and 59.0-62.3%, respectively. The complete circular genome of strain GM2-3-6-6 was 4,365,762 bp in length with a DNA G + C content of 35.0%. The respiratory quinone was MK-7. The major polar lipids consisted of phosphatidylethanolamine, two unidentified phospholipids, one unidentified aminoglycolipid, one unidentified aminolipid and four other unidentified lipids. The major fatty acids were iso-C, iso-C G, summed feature 3 (Cω7c and/or Cω6c), and iso-C 3-OH. Based on genomic, phenotypic, and chemotaxonomic characterizations, strain GM2-3-6-6 represents a novel species of a novel genus, for which the name Paracrocinitomix mangrovi gen. nov., sp. nov. is proposed. The type strain is GM2-3-6-6 (= MCCC 1K04831 = KCTC 82931). Additionally, phylogenomic analysis of the type strains of the family Schleiferiaceae and family Cryomorphaceae related members including uncultivated bacteria, was performed using the Genome Taxonomic Database toolkit (GTDB-Tk). Based on 16S rRNA gene phylogeny and genomic features, two novel families, Phaeocystidibacteraceae fam. nov. and Owenweeksiaceae fam. nov. are proposed. An emended description of the family Schleiferiaceae is also proposed.