A Gram-stain-negative, strictly aerobic, rod-shaped and motile bacterium with bipolar flagella, designated G-43T, was isolated from a surface seawater sample collected from an aquaculture in Guangxi, PR China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain G-43T was most closely related to the family Oceanospirillaceae and distantly to the most closely related genera Venatorbacter and Thalassolituus (95.52 % and 94.45-94.76 % 16S rRNA gene sequence similarity, respectively), while similarity values to other Oceanospirillaceae type strains were lower than 94.0 %. Strain G-43T was found to grow at 4-30 °C (optimum, 25-28 °C), pH 6-9.0 (optimum, pH 7.0) and with 0-4.0 % NaCl (w/v; optimum at 2 % NaCl). Chemotaxonomic analysis of strain G-43T indicated that the sole respiratory quinone was ubiquinone-8, the predominant cellular fatty acids were C16 : 0, summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), and the major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, aminolipid, diphosphatidylglycerol, phospholipids and an unidentified lipid. The G+C content of the genomic DNA was 55.4 mol%. The phylogenetic, genotypic, phenotypic and chemotaxonomic data demonstrate that strain G-43T represents a novel species in a novel genus within the family Oceanospirillaceae, for which the name Parathalassolituus penaei gen. nov., sp. nov. is proposed. Strain G-43T (=KCTC 72750T= CCTCC AB 2022321T) is the type and only strain of Parathalassolituus penaei.
Keywords: Parathalassolituus penaei; aquaculture; halophilic; novel genus.