Top panel: kernel density estimator in the redshift distribution of the galaxy cluster region: 0.28 ≤ z ≤ 0.34. Red lines show the redshift cuts of the three substructures identified: SS1 in 0.2850 ≤ z < 0.3029, SS2 with 0.3029 ≤ z < 0.3243, and SS3 covering 0.3243 ≤ z < 0.3380. Vertical black segments are the clustercentric radial distance of the galaxies. Bottom panel: galaxies of the three substructures in the mass-metallicity plane. Sky-blue triangles, black dots, and red dots represent SS1, SS2, and SS3, respectively. The black line is the cMZR.