Aims: We revisit the scaling relations and star-forming histories of local elliptical galaxies using a novel selection method applied to the Sloan Digital Sky Survey DR7. Methods: We combine two probability-based automated spectroscopic and morphological classifications of ~600 000 galaxies with z < 0.25 to isolate true elliptical galaxies. Our sample selection method does not introduce artificial cuts into the parameters describing the galaxy but instead associates every object with a weight measuring the probability of being in a given spectro-morphological class. Thus, the sample minimizes the selection biases. Results: We show that morphologically defined ellipticals are basically distributed into three spectral classes, which dominate at different stellar masses. The bulk of the population (~50%) is formed by a well-defined class of galaxies with old stellar populations that formed their stars at very early epochs in a short episode of star formation. They dominate the scaling relations of elliptical galaxies known from previous works and represent the canonical elliptical class. At the low mass end, we find a population of ellipticals with relatively large shapes and smaller velocity dispersions at fixed stellar mass, which seem to have experienced a more recent episode of star formation probably triggered by gas-rich minor mergers. The high mass end tends to be dominated by a third spectral class that is slightly more metal rich and hosts more efficient stellar formation than the reference class. This third class contributes to the curvature in the mass-size relation at high masses reported in previous works. Our method is therefore able to isolate the typical spectra of elliptical galaxies following different evolutionary pathways. Appendix A is available in electronic form at http://www.aanda.org