Local relation between galaxy intrinsic shapes and the local fraction of accreted stars for galaxies with M_* ≥ 10^10.6 M_⊙. The top panels show q(f_exsitu), the bottom panels T(f_exsitu). In the left panels, galaxies are color-coded according to the fraction of accreted mass from major mergers ΔM_*, major/M_*, in the right panels colors indicate the fraction of in-situ stars produced since z = 1, Δ_{insitu, z ≤ 1}. The local ex-situ fraction parametrizes the different galaxy accretion histories: the break in q(f_exsitu) is driven by recent dry major mergers in massive systems; the most triaxial galaxies are systems with the lowest fractions of recently accreted cold gas, while low T stellar halos are formed in more gas-rich systems.