[Objective] A bacterium MU2A-22T, which was isolated from 131-year-old volcanic deposits of Miyake-jima island (Japan), has been characterized for its capability of thiosulfate oxidizing. [Methods] The culture-based method was used to isolate and identify strain MU2A-22T for its phenotypic characteristics and taxonomic position. [Results] The strain MU2A-22T was Gram-negative, short rod- to coccus-shaped. This bacterium could utilize D-glucose, L-arabinose, gluconate, adipate and dL-malate as sole carbon source. Strain MU2A-22T was able to use thiosulfate as an energy source with the optimum concentration of 2.5 mmol/L. The optimum growth condition was 25 °C?30 °C and pH was 6.0?8.0 respectively. 16S rRNA gene sequence analysis indicated that this strain was closely related to Paracoccus solventivorans 6637T within Alphaprotebacteria (97% 16S rRNA gene sequence similarity). Its possess of the large-subunit gene of ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcL) has also been identified. The cellular fatty acid profiles was characterized of the genus Paracoccus. The major fatty acids (>10%) were C18:1(74.7%) and C18:0(12.1%). DNA-DNA relatedness between strain MU2A-22T and P. solventivorans 6637T was 49.3%. G+C contents was 66.5%?66.7%. [Conclusion] As for the above results, strain MU2A-22T seemed to be a novel species in the genus Paracoccus with its accession number of GQ452286 and the name of Paracoccus scorialis sp. nov. was proposed.