Homo heidelbergensis is the species name now given to a range of specimens from about 800,000 years ago to the appearance of anatomically modern Homo sapiens. The species name was originally proposed for the fossil mandible discovered at Mauer, a town near Heidelberg, Germany. It is a nearly complete early human mandible that is very robustly built, but lacks a chin. Additional finds of early humans with morphological attributes of both modern humans and Homo erectus have shown that the transition from early and middle Pleistocene forms and the morphology of modern humankind was not a neat transition that could be easily explained.
For many years, scientists placed any problematic specimens displaying mixtures of "erectus-like" and "modern" traits into a confusing category: "Archaic" Homo sapiens (basically meaning any Homo sapiens that didn't look quite modern). Recently, it has been proposed to separate these individuals into a distinct species. For this purpose, the Mauer mandible, and the species name Homo heidelbergensis has seniority.