H. neanderthalensis

    H. sapiens

      H. ergaster is easily distinguished from earlier and more basal species of Homo, notably H. habilis and H. rudolfensis, by a number of features that align them, and their inferred lifestyle, more closely to modern humans than to earlier and contemporary hominins. As compared to their relatives, H. ergaster had body proportions more similar to later members of the genus Homo, notably relatively long legs which would have made them obligately bipedal. The teeth and jaws of H. ergaster are also relatively smaller than those of H. habilis and H. rudolfensis, indicating a major change in diet.[15] In 1999, palaeoanthropologists Bernard Wood and Mark Collard argued that the conventional criteria for assigning species to the genus Homo were flawed and that early and basal species, such as H. habilis and H. rudolfensis, might appropriately be reclassified as ancestral australopithecines. In their view, the true earliest representative of Homo was H. ergaster.[16]