The long-lived radionuclides Nb, Tc, Tc and Sm are not among the classically defined p-nuclei as they no longer occur naturally on Earth. By the above definition, however, they are also p-nuclei because they cannot be made in either the s- or the r-process. From the discovery of their decay products in presolar grains it can be inferred that at least Nb and Sm were present in the solar nebula. This offers the possibility to estimate the time since the last production of these p-nuclei before the formation of the Solar System.