Caulobacter inopinatus sp. nov., from seawater off O‘ahu, Hawai‘i, and emended description of the genus Caulobacter

A Gram-negative, curved rod and prosthecate bacterium designated as 73W^T was isolated from seawater collected at an O'ahu, Hawai'i beach. Based on 1,468 nt of the strain's 16S rRNA gene, the nearest neighbours are <i>Caulobacter segnis</i> ATCC 21756^T (97.4%), <i>Caulobacter rhizosphaerae</i> 7F14^T (97.5%), <i>Caulobacter vibrioides</i> CB51^T (97.3%), 'Caulobacter zeae' 410^T (1,402/1,440, 97.4%), <i>Caulobacter mirabilis</i> FWC 38^T (1,398/1,435, 97.4%) and 'Caulobacter endophyticus' 774^T (97.3%). Cells are motile by a single polar flagellum. The strain is oxidase and catalase positive, aerobic and microaerophilic and grows between 6 and 39 °C. Major fatty acids in whole cells of 73W^T are cis-11-octadecenoic acid/cis-12-octadecenoic acid (50.6%) and hexadecenoic acid (18.2%). The G+C content of the genome is 67.6%. Based on phenotypic and genotypic differences between strain 73W^T and extant <i>Caulobacter</i> species, we propose that strain 73W^T represents a novel <i>Caulobacter</i> species, for which the name <i>Caulobacter inopinatus</i> sp. nov. is proposed to accommodate strain 73W^T as the type strain (DSM 112346^T=LMG 33179^T=NCTC 14601^T). The description of the genus <i>Caulobacter</i> is emended to reflect the presence in all species of 3-hydroxydodecanoic acid and hexadecanoic acid.