The Plio-Pleistocene volcanic sediments at Laetoli in northern Tanzania, especially those within the Upper Laetolil Beds preserve a plethora of fossilized fauna remains and animal trackways that provide evidence on human origins in eastern Africa 3.66 million years ago. Of particular interests are hominin remains and footprints assigned to Australopithecus afarensis that have been recovered at Localities 7 and 8 at Sites A, G, and S with additional hominin remains assigned to Paranthropus aethiopicus discovered at Laetoli in 2002, which expands the range of this species south of the Equator. With more discoveries of hominin remains in eastern Africa, both morphological and taxonomic diversity of Plio-Pleistocene hominins reveal a different story of hominin diversity than that have been portrayed in the past. For example, Australopithecus afarensis which has been joined by Australopithecus bahrelghazali, Kenyanthropus platyops, and Australopithecus deyiremeda, overlapped in time with Australopithecus anamensis at various sites within eastern Africa, thus complicating the ancestral-descendant relationships. While these Pliocene hominins exhibit morphological diversity, their taxonomic distinctions are highly debatable. For example, the Pliocene hominin foot from Burtele, which is taxonomically unassigned and the partial skeleton of Australopithecus afarensis (nick-named Kadanuum KSD-VP-1/1) from Woranso-Mille possess distinct anatomical features, clearly demonstrating that Lucy and her companions were not the only hominins roaming the East African Pliocene landscape. Here I discuss the discovery of two robust-like hominin mandibular fragments from Upper Laetolil Beds (between Tuffs 7 and 8) in combination with renewed work at the A hominin footprints at Site A and their implications to hominin diversity at Laetoli.
