Smith, Fred H

RERO DOC Digital Library

BOOK REVIEWFossil Hominins: NeandertalsNeanderthals Revisited. New Approaches and Perspectives. Editedby Katarina Harvati and Terry Harrison. Dordrecht: Springer.2006. 332 pp., $129.00 (cloth). ISBN 1-4020-5120-4Fred H. SmithPublished online: 23 October 2007# Springer Science + Business Media, LLC 2007In science, the more data available on a particular phenomenon, the more detailed and precisethe questions articulated by scientists concerning those data and the phenomenon pertinentthereto. So it is with our close kin, the Neandertals. We know more about the Neandertals thanwe do about any fossil primate – perhaps any fossil vertebrate – “species.” Not only do wehave an excellent handle on their total morphological pattern, we also have a solid picture oftheir behavior (to the extent possible from fossils and archaeology), their developmentalbiology, and increasingly even their genome. Neanderthals Revisited aims to provide a currentview of the questions being posed about Neandertals and an assessment of the plethora of databeing generated to address those questions. Unlike the other top quality recent edited volumefocusing on the “Neandertal question” (Conard 2006), Neanderthals Revisited dealsexclusively with the biological issues, and this focus allows a more in-depth and broaderconsideration of those issues. Perhaps its most significant feature is the breadth of ideas andinterpretations in the volume. Readers will gain an appreciation of the diversity of scientificperspectives on the Neandertals and their relationship to us rather than simply getting one sideof the story. The result is an excellent and extremely useful compendium of approaches andperspectives, including some very novel ones.Of the 17 original papers in the volume, two deal with the currently high-profile impact ofgenetic studies on understanding late Pleistocene human evolution, and these two illustratewell the diversity of perspectives on just what the genetic data can tell us. D. Serre and S.Pääbo review their findings based on ancient mitochondrial (mt) DNA and reiterate theirprevious conclusions that these data provide no evidence of introgression between Neandertalsand early modern humans. They do note that low levels of gene flow are not precluded bythese data, but the clear message is that these data show Neandertals to be substantiallydifferent from us. J. Hawks takes a very different view. He marshals evidence to demonstratethat mtDNA is not selectively neutral and argues that the modern-Neandertal difference mayresult from a recent “selective sweep” of human mtDNA. In stark contrast to Serre and Pääbo’sconfidence about the future contributions of genetic studies, Hawks (p. 221) posits that theimpact of selection makes “Neanderthal mtDNA variation phylogenetically uninformative.”J Mammal Evol (2008) 15:219–222DOI 10.1007/s10914-007-9064-4F. H. Smith (*)Department of Anthropology, Loyola University Chicago, 6525 North Sheridan Road, Chicago, IL 60626,USAe-mail: fsmith3@luc.eduThe majority of papers deals with the interpretation of Neandertal morphology, and adiversity of methodologies and interpretations emerge. K. Harvati and D. Weaver comparecranial vault, facial, and temporal bone data among modern human populations, compared togenetic and climatic variables. They determine facial variation to be more climate related andthat, while the other two morphological areas both correlated better with neutral geneticdistances, temporal bone form was the better indicator of “genetic” relationship. Theirassessment of Neandertal temporal bone patterns compared to the moderns lead them to theconclusion that Neandertals were a distinct lineage and thus, species. G. Bräuer and colleaguesreach a similar conclusion about Neandertal-modern relationships based on multivariate andunivariate metrical cranial analyses focused on the Mladeč early modern European sample.Interestingly, given the results of the previous Havarti/Weaver study, a significant part of thisanalysis focuses on the face. However, for both the face and the vault, Bräuer and colleaguesfind no evidence of Neandertal contribution. Several other papers focus on various aspects ofNeandertal morphology (Tattersall/Schwartz, Bruner/Manzi, Niewoehner, Bailey/Hublin,Pearson and colleagues, Rosas and colleagues, Ponce de León/Zollikofer) and generallyemphasize Neandertal distinctiveness. However, both Niewoehner (hand) and the Pearsongroup (upper limb) see the distinctions as primarily related to activity/behavioral differences.S. Bailey and J-J. Hublin focus on dental morphology to demonstrate that Neandertalsproduced the Châtelperronian at La Grotte du Renne (Arcy-sur-Cure) in France. Thisdemonstration takes on particular importance given the recent assertion by O. Bar-Yosef (inConard 2006) that the Neandertal-Châtelperronian association in France is suspect. Obviously,if Bar-Yosef is correct–and the Châtelperronian is produced by early modern people–currentperspectives on modern human cultural and biological origins in Europe would besubstantively altered.Morphology-based studies by J. Ahern and J.-L. Voisin conclude that Neandertals and earlymodern people were capable of some degree of interbreeding. Ahern focuses on non-metricfeatures and compares frequency differences in these traits between Neandertals and earlymodern humans with the differences between recent Amerindians and Euroamericans. He findsthat the differences are not statistically significantly greater in the Neandertal-early modernhuman comparison than in the Amerindian-Euroamerican comparisons. He concludes that thehypothesis that Neandertals and early moderns represent the same morphospecies cannot berefuted with these data, but he goes on to question the utility of the morphospecies concept inevolutionary studies. It should be noted that Ahern’s study focuses on morphological detailsrather than patterns of major morphological form. Voisin asserts that Neandertals underwent aspeciation by distance, meaning that in the Near East Neandertals and early moderns were stillcapable of interbreeding as were populations of Neandertals and modern humans in the easternpart of Europe. However, the western European Neandertals had been isolated enough fromnon-Neandertal populations that they were likely not to have interbred with invading earlymodern populations. Similar morphological clines have been noted before for Neandertals,initially by F.C. Howell (1957) and then others, but Voisin’s model certainly represents a veryrobust, novel approach.The contribution by M. Ponce de León and C. Zollikofer stresses the importance ofontogenetic data to later hominin lineage divergence. They analyze craniofacial developmentfrom infant to adult in the two species of Pan compared to Neandertals and modern humans.They find that both lineage divergences (common chimpanzee/bonobo and Neandertal/modernhuman) are characterized by the latter form in each comparison exhibiting “abridged”spatiotemporal developmental patterns compared to the former, but the Neandertal/moderndivergence appears to result from differences in prenatal developmental patterning whereas the220 J Mammal Evol (2008) 15:219–222divergence in Pan is evident postnatally. In a second paper, Zollikofer and Ponce de Leónillustrate the usefulness of computer modeling in investigating the role of specific factors inchanging developmental patterns. A. Rosas and colleagues also invoke developmentalpatterning in the origin of Neandertals. They suggest a two-phased model in which changesin ontogenetic dynamics of the skull produce the Neandertal morph and establish theNeandertal lineage as a distinct species.In a unique approach to the role of climatic adaptation in Neandertal body form, S.Churchill revisits the idea that the large thoraces of Neandertals represent a cold adaptation.Using a bioenergetics approach and working with a half-size reconstruction of the La Ferrassie1 male Neandertal, he determines that Neandertals had more elevated basal metabolic ratesthan previously thought. Churchill concludes that the expanded chests likely functioned moreto fill the enhanced oxygen demand of the higher BMR than to provide strict adherence toBergmann’s rule. He also makes the point that higher energetic costs of thermoregulation inNeandertals may have reduced the energy directed to reproduction. This may provide a furtherrationale for explaining the relative rarity of Neandertals on the landscape. C. Stringer alsoexamines the role of climate–in this case climatic instability–on the fate of the Neandertals. Hesees such climatic factors playing a determining role in Neandertal extinction by providing astressor that Neandertal populations could not adequately respond to. Stringer also notes theimpact of more accurate dating on our picture of Neandertal-early modern interactions andsuggests that Neandertals and early modern humans might well be best characterized asallotaxa.Yet another novel and informative approach is provided by T. Holliday. He provides adiscussion of the time it takes for mammalian species to achieve reproductive isolation, basedon both molecular and paleontological data. As it turns out, the molecular and fossil evidencesuggests minimum time spans of 1.4 million and 2 million years, respectively. Using amaximum estimate of Neandertal-modern human lineage divergence at ∼700,000 years,Holliday concludes that they likely remained interfertile. There simply was not enough timesince divergence for complete reproductive isolation to develop. However, he does assert thatthese two groups should still be considered separate evolutionary species and suggests that thedearth of evidence for interbreeding is that we either do not recognize it or that differences inappearance or behavior would prevent recognition of the other group as potential mates. Frommy perspective, I see Holliday’s study dovetailing nicely with Voisin’s model. It seems logicalthat geographic separation of populations could enhance the time effect. Thus, it may well bethat interfertility would be less likely as one moves West, where Neandertals may have beenthe most isolated from non-Neandertal populations. But the bottom line is that both thesestudies, along with those of Ahern and Hawks, certainly challenge any attribution ofreproductive exclusivity to the Neandertals.As I hope this review reflects, Neanderthals Revisited provides very valuable contributionsto our understanding of Neandertal biology and systematics. The fact that they do not all agreeon the final conclusion of how Neandertals are related to us is an accurate reflection of the stateof “Neandertal studies.” The lay media’s claims that Neandertals have been proven to be ourcousins but not to have contributed to our ancestry are just not true. What is clear is that ifNeandertals did contribute, it does not appear to have been a major contribution. Still it is notevident that such a contribution was as insignificant as some suggest. Regardless of how oneviews the evidence, Neanderthals Revisited is a fine volume that moves our understanding ofthese complex issues forward. I consider it a must read for anyone interested in any aspect ofhominin evolution and believe it will stand for many years as the fundamental reference for therole of the Neandertals in our evolutionary history.J Mammal Evol (2008) 15:219–222 221ReferencesConard N (ed) (2006) When Neanderthals and modern humans met. Kerns, Tübingen, p 501Howell FC (1957) The evolutionary significance of variation and varieties of “Neanderthal” man. Q Rev Biol32:330–347222 J Mammal Evol (2008) 15:219–222

Fossil Hominins: Neandertals : [book review]

Abstract

Similar works

Full text

Available Versions

RERO DOC Digital Library