An aerobic, halotolerant, Gram-negative bacterium was isolated from the sea urchin Strongylocentrotus intermedius and subjected to taxonomic characterization. The strain, designated KMM 6042(T), was rod-shaped, motile and yellow-pigmented. Phylogenetic analysis indicated that the strain was most closely related to the type strain of Altererythrobacter dongtanensis, and the level of 16S rRNA gene sequence similarity between the two was 99.0 %. However, the DNA-DNA relatedness between the two strains was 34.4 ± 7.6 %. Physiological and chemotaxonomic properties clearly distinguished the novel strain from other species of the genus Altererythrobacter. It is thus evident from the phylogenetic and phenotypic analyses that strain KMM 6042(T) merits recognition as a novel species of the genus Altererythrobacter, for which the name Altererythrobacter troitsensis sp. nov. (type strain, KMM 6042(T) = KCTC 12303(T) = JCM 17037(T)) is proposed.