Sky distribution of galaxies in the redshift range of the most significantly detected spectroscopic protostructure in the CFHTLS-D1 field (Cl J0227-0421). Galaxies with secure spectroscopic redshifts are plotted as red diamonds, those with less secure spectroscopic redshifts are shown as blue Xs. Green stars denote those galaxies hosting a type-1 AGN and the cyan circle denotes the lone X-ray AGN host at these redshifts. Plotted in the background are all galaxies in the CFHTLS-D1 field with secure spectroscopic redshifts z_spec> 1.5. The dashed circle designates 3 Mpc from the adopted center of the protostructure and is used in conjunction with the redshift range to define membership (see Sect. 3.1). The VIMOS footprint is clearly visible, and coverage gaps in the CFHTLS-D1 spectroscopy are apparent throughout the field and to the north of the protostructure.