Four novel strains, designated p1-h21 T /p2-l61 and p3-h83 T /p4-l81, characterized as Gram-stain-negative, oxidase-positive, catalase-positive, obligately aerobic, non-motile and rod-shaped, isolated from blowhole swab samples of Yangtze finless porpoise ( Neophocaena asiaeorientalis asiaeorientalis ), collected from Hubei Province, China. Pairwise sequence comparisons of the 16S rRNA genes showed that these isolates were separated into two species. Strains p1-h21 T and p2-l61 were most closely related to Paracoccus endophyticus SYSUP0003 T (97.18% similarity) and Paracoccus aurantiacus TK008 T (97.03% similarity), whereas strains p3-h83 T and p4-l81 exhibited 96.89% similarity to Paracoccus kondratievae GB T , and 96.53% similarity to Phaeovulum vinaykumarii DSM 18714 T . The DNA G+C contents of type strains p1-h21 T and p3-h83 T are 65.7 mol% and 66.9 mol%, respectively. These strains had summed feature 8 (comprising C 18 : 1 ω 6 c and/or C 18 : 1 ω 7 c ) as major cellular fatty acids, ubiquinone 10 as the sole respiratory quinone and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylcholine as major polar lipids, which are typical for members of the genus Paracoccus . However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the four novel strains and their reference strains (ANI <75.3%, dDDH <20.5%) are lower than the species delineation thresholds, along with distinct phenotypic and biochemical characteristics, distinguishing them from their closest relatives and other recognized Paracoccus species. Therefore, strains p1-h21 T /p2-l61 and p3-h83 T /p4-l81 represent two novel species in the genus Paracoccus , for which the names Paracoccus jiaweipingae sp. nov. and Paracoccus zhouxuedongae sp. nov. are proposed, with p1-h21 T (=GDMCC 1.4971 T =JCM 37697 T ) and p3-h83 T (=GDMCC 1.4972 T =JCM 37698 T ) as type strains.
Xiao et al. (Wed,) studied this question.