Two bacterial strains, designated D2-102 T and MBA3-11 T , were isolated from mangrove surface sediment and cordgrass Spartina alterniflora root, respectively, using the dilution-to-extinction method. The two strains were Gram-stain-negative, coccus-shaped, non-motile, catalase-positive and oxidase-positive. The 16S rRNA genes of the two strains had the highest sequence similarities with Actomonas aquatica WL0086 T of 97.6–98.4%, followed by Synoicihabitans lomoniglobus LMO-M01 T of 95.5–95.7%. Phylogeny of the 16S rRNA gene placed the two strains into two novel monophyletic branches neighboured by Actomonas and Synoicihabitans of the phylum Verrucomicrobiota . The digital DNA–DNA hybridization and average nucleotide identity among strain D2-102 T , strain MBA3-11 T , A. aquatica WL0086 T and S. lomoniglobus LMO-M01 T were 19.5–22.8%, and 74.6–79.7%, respectively. The respiratory quinones of the two strains were both menaquinone-7. The major fatty acids (>10%) of the two strains were C 16:0 , iso-C 14:0 and anteiso-C 15:0 . The major polar lipids of the two strains included diphosphatidylglycerol, phosphatidylglycerol and two phospholipids, while phosphatidylethanolamine was only present in strain MBA3-11 T . Based on the polyphasic taxonomic study, strains D2-102 T and MBA3-11 T represented two novel species, and thus, Actomonas mangrovi sp. nov., and Actomonas spartinae sp. nov. were proposed with type strain D2-102 T (=MCCC 1K09973 T =KCTC 102446 T ) and type strain MBA3-11 T (=MCCC 1K09525 T =KCTC 102445 T ), respectively. Furthermore, based on the phylogeny of the 16S rRNA gene, genomic, phenotypic (including chemotaxonomic) analyses, S. lomoniglobus Ahmad et al . 2024 should be transferred to the genus Actomonas as Actomonas lomoniglobus comb. nov. This study expanded the bacterial diversity and ecological distribution of the genus Actomonas .
Wang et al. (2026) studied this question.