RASS image centred on MCXC J2356.0-0129 position, an SGP cluster previously without redshift. The X-ray emission is peaked on the AGN MCG+00-01-003 at ɀ_spec = 0.0370, a member of the [DZ2015] 540 group at ɀ = 0.038 (Díaz-Giménez & Zandivarez 2015). Other group members are marked by magenta plusses and the half-virial radius by a magenta circle. The contours from the wavelet filtered RASS image (green lines) show that the emission is extended, in the direction of the group centre, D = 8.8′ from the MCG galaxy member. We identified MCXC J2356.0-0129 with the [DZ2015] 540 group, noting that the emission is likely highly contaminated by a non-central AGN group member, which explains the offset between the X–ray and optical positions.