Homo rudolfensis

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This skull, catalog number KNM-ER 1470, is one of the most famous fossil finds in the history of paleoanthropology. Discovered in 1972 in Kenya by Bernard Ngeneo and Richard Leakey (son of Louis and Mary), it was originally seen as dramatic vindication of the legitimacy of the species Homo habilis, which to that time was under dispute due to the relative paucity of fossils yet found. (Since 1972 other Homo habilis finds have been made and this is no longer a problem.)

It is ironic then that in the several decades since "ER 1470" (as it is commonly known) was found, there have been enough other early Homo finds that paleoanthropologists have come to see that "1470" and (for example) OH 24 actually are disparate species, and thus that there were at least two distinct contemporary early species of the genus Homo.

KNM-ER 1470 carries a potassium-argon date of 1.85 MY and a measured cranial capacity of 775 ml. Despite the fact that this specimen has a larger cranial capacity than OH 24, this is not evidence that makes Homo rudolfensis ancestral to modern humans because "1470" is probably male; thus the difference in cranial capacities between it and OH 24 may be due to sexual dimorphism, which was similar in this species to that seen in Homo habilis.

Both species of early Homo are considered likely to have made the Oldowan pebble tools, and they apparently overlapped in both range (East Africa) and time period (see Homo habilis). Nonetheless the growing consensus among paleoanthropologists is that H. habilis is the better candidate for being on the ancestral line leading to modern people.

Anthropology