Neanderthal news: Extinct species exhibits variability

What is it about the Neanderthals? No other extinct hominin captures the popular and scientific imagination the way the Neanderthals do. Virtually every aspect of their being, their origins, behavior, appearance, interactions with other hominins, extinction (or survival?) is passionately debated not just among scientists, but also the interested public. Their fate has been the subject of immensely popular novels, several films, and countless television documentaries. There have even been serious calls to ‘‘revive’’ them by using fossil DNA. Why is it that people care so much more about these later Pleistocene fossils than they seem to about earlier hominins? At most, the Neanderthals are ancestral only to some of us. Earlier hominins, like Homo heidelbergensis or Homo erectus/ergaster, are ancestors of all of us. Why is it that the Neanderthals are, as Trinkaus and Shipman aptly put it, ‘‘images of ourselves’’? Homo neanderthalensis lived in western Eurasia between 250-30 Ka. Most of their habitation sites and fossils are associated with faunas from temperate woodland and steppe habitats. The limits of their eastern range are unclear, with the southernmost fossils coming from Israel and the easternmost from Uzbekistan. Neanderthal crania are distinct in featuring a divided brow-ridge, pronounced mid-facial prognathism, a projecting occipital bone, and teeth with enlarged pulp cavities and incompletely divided roots. Below the neck, the Neanderthals were ruggedly built, with thick cortical bone, enlarged joint surface areas, a barrel chest, wide pelvis, and relatively short distal limb segments. Some of these features occur piecemeal among European H. heidelbergensis fossils dating to ca. 300 Ka, and not in their African counterparts. This suggests the Neanderthals evolved in western Eurasia. The last appearance dates for Neanderthal fossils range between 45 Ka in the East Mediterranean Levant and 28 or 30 Ka in Iberia. The presence of Neanderthal features among some European Upper Paleolithic H. sapiens fossils, as well as the difficulty of discriminating between Neanderthal and H. sapiens fossils from Southwest Asia has long fueled hypotheses of gene flow between the Neanderthals and early H. sapiens. These continuity hypotheses have found support from analyses of aDNA from fossils and variation in the DNA of living humans, suggesting that some significant portion of Eurasian humans, and possibly some North Africans as well, have genes that are traceable to Neanderthal ancestors. Neanderthal fossils are associated with Middle Paleolithic ‘‘Mousterian’’ stone-tool assemblages and a handful of so-called ‘‘transitional’’ MiddleUpper Paleolithic industries, mainly from Mediterranean Europe. Neanderthal sites differ from those of their H. heidelbergensis predecessors in showing abundant evidence of controlled use of fire. Faunal remains from Neanderthal sites preserve evidence of a broad diet that included birds, fish, shellfish, reptiles, and small mammals, as well as large terrestrial mammals ranging from gazelle and ibex to aurochs, bison, rhinos, and mammoths. As among sites of roughly contemporaneous H. sapiens, there are occasional finds of mineral pigments, perforated shells, modified bone tools, burials (sometimes with mortuary furnishings), and occasional evidence of cannibalism (inferred from cut-marks and bone breakage). Such symbolic evidence as has been claimed for Neanderthal and early H. sapiens contexts before ca. 40-50 Ka share a quality of idiosyncracy, rarely taking the same form at more than one site. Compared to contexts associated with Pleistocene H. sapiens, Neanderthal contexts lack evidence of nonculinary pyrotechnology, such as heattreatment of stone or the production of ceramics; complex projectile technology, such as bow and arrow, spearthrower, and dart; figurative and abstract notation; ocean-going watercraft; freestanding architecture; food storage; or either plant or animal domestication. Attaching the definitive article to any proper noun (‘‘the Neanderthals’’) or using a proper noun as an adjective (‘‘Neanderthal sites’’), as this review has done up to this point, inevitably shifts the focus of discussion toward modality and away from variability. And yet variability is of paramount evolutionary significance. Modalities in genotypes, phenotypes, and behavior are merely byproducts of selection on variability. One interesting theme emerging in recent books on Neanderthal paleoanthropology is increased recognition of variability in their fossil, genetic, and archeological records. In 2006, it was 150 years since the discovery and recognition of the first Neanderthal fossil from Feldhöfer, Germany. A pair of volumes in the Springer Vertebrate Paleobiology BOOK REVIEW