The status of Mastodon angustidens pygmaeus Depéret, 1897 (Proboscidea, Mammalia): The contribution of X-ray tomography

The status of Mastodon angustidens pygmaeus Depéret, 1897 is discussed on the basis of an examination of the holotype (a broken lower molar) with tomography using X-rays, and on a review of the previous taxonomic hypotheses. The conclusion is that the holotype is a possible supernumerary post-m3 molar that may be that of a tetralophodont gomphothere. “M. angustidens pygmaeus” is then a nomen dubium that should only be used in relation to the holotype.