Three strains of anaerobic, variably pigmenting, Gram-negative bacilli isolated from human oral mucosal tissue were subjected to a comprehensive range of phenotypic and genotypic tests and were found to comprise a homogeneous group. 16S rRNA gene sequence analysis and DNA–DNA hybridization revealed that the strains constituted a novel group within the genus Prevotella, being most closely related to Prevotella melaninogenica and Prevotella veroralis. A novel species, Prevotella histicola sp. nov., is proposed to accommodate these strains. Prevotella histicola is saccharolytic and produces acetic acid and succinic acid as major end products of fermentation and trace to minor amounts of isovaleric acid and lactic acid. The G+C content of the DNA of the type strain is 43 mol%. The type strain of Prevotella histicola is T05-04T (=DSM 19854T=CCUG 55407T).
A Gram-negative, non-motile, rod-shaped, agarolytic bacterial strain, designated JW-26T, was isolated from seawater off Jeju Island in Korea, and was subjected to a polyphasic taxonomic investigation. Strain JW-26T grew optimally at pH 7.0–8.0, at 30 °C and in the presence of approximately 2 % (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain JW-26T joins Tamlana crocina HST1-43T, with which it exhibited a 16S rRNA gene sequence similarity value of 95.5 %. Strain JW-26T contained MK-6 as the predominant menaquinone and iso-C15 : 0, C15 : 0 and iso-C15 : 1 as the major fatty acids. The DNA G+C content was 36.8 mol%. There were no distinct phenotypic and, particularly, chemotaxonomic properties to differentiate strain JW-26T from the genus Tamlana. DNA–DNA relatedness data and differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain JW-26T is distinguishable from the type strain of T. crocina. On the basis of phenotypic, phylogenetic and genetic data, therefore, strain JW-26T represents a novel species within the genus Tamlana, for which the name Tamlana agarivorans sp. nov. is proposed. The type strain is JW-26T (=KCTC 22176T =CCUG 55327T).