Journal of Biogeography (J. Biogeogr.) (2009)

EDITORIAL

The first , the second living and fossil . The authors are quite therefore may well gain wide attention orangutan and the third aware that their hypothesis is in conflict in the scientific and popular press. The with the consensus hypothesis based on main facet of the paper that is worthy of molecular systematics, but argue that this is editorial comment is that their analysis so because ‘Molecular analyses are compro- challenges, or rather dismisses, a large Of all the topics in evolutionary , it is mised by phenetic procedures such as range of molecular (including modern hard to think of any that is of greater general alignment and are probably based on prim- genomics-based) analyses that support the interest than the topic of where humans itive retentions’ (more on this topic below). alternative phylogenetic hypothesis that arose and from what ancestors. Several The study becomes relevant for this humans are in fact more closely related decades into the recent renaissance in phy- journal when the phylogenetic conclusions to (as reflected in the title of logenetics generated by the advent of are interpreted in an historical biogeo- Diamond’s book; above). Grehan and molecular methods for determining evolu- graphical framework. The controversial Schwartz contend that the morphological tionary relationships, the prevailing view and infrequently used panbiogeographical data they have selected as the basis for among anthropologists is that the closest method of track analysis is their method of interpreting evolutionary relationships are living relatives of humans are the African choice. This method interprets disjunct more robust and reliable for this purpose great apes, with the chimpanzee and (separated) distributions of related taxa as than the majority of the genetic evidence forming the sister-lineage to humans, fol- having derived principally through the considered by other authors. Unfortu- lowed by the gorilla; these species are next break-up of the range of an ancestral form nately, as one of the reviewers of the joined on the phylogenetic tree by species by the development of environmental bar- manuscript pointed out, the identification with Southeast Asian distributions – the riers (a process termed vicariance), with of characters and the judgement of their orangutan, and then the and subsequent evolution of descendant forms significance, is a subjective procedure and siamangs. This phylogenetic hypothesis – in isolation. And so, by implementing their depends to a large extent on how the corroborated by multiple independent alternative phylogenetic results in a track individual worker interprets the characters. molecular analyses – is often conveyed to a analysis, Grehan and Schwartz postulate The manuscript did not exactly succeed in broader audience [e.g., ’s the equally controversial hypothesis that convincing the journal’s reviewers that the (1992) book The third chimpanzee: the the ancestors of humans arrived in Africa ‘second orangutan’ interpretation is to be evolution and future of the animal, independently of the other African great preferred over the more popular ‘third and Richard Dawkins’ (2004) book The apes. chimpanzee’ scenario, but was felt to be a ancestor’s tale] as having been so generally Historical biogeography is a discipline contribution worth putting out to the test accepted by the scientific community that it characterized by divergent schools of of further scientific scrutiny. is without serious challenge to its veracity. thought, and in this paper the authors The strength of the paper by And so, it may come as a surprise that the have chosen to rely on two approaches Grehan and Schwartz as a contribution Journal of Biogeography would choose to that each are increasingly utilized by to the debate over human origins is, in publish the paper by Grehan & Schwartz a minority of modern practitioners: our view, that the authors have pro- (2009), which challenges this view and morphological systematics, with explicit vided a clear account of their hypothesis, provides a detailed account of an alternative denial of the theoretical underpinnings of the assumptions that have gone into their evolutionary and biogeographical scenario. molecular systematics; and panbiogeo- analysis, the data they have so painstak- In this study, Grehan and Schwartz provide graphical track analysis. Within science, ingly compiled and used, and the relation- a radically different hypothesis of great being in a minority does not mean that ship of their findings to the existing phylogeny by positing that humans are most you are wrong of course. Regular readers of literature on the topic. While this per- closely related to the orangutan rather than this journal will be aware of these differ- spective might superficially appear to be to the chimpanzee and bonobo, a view that ences in perspective, method and inter- nonsensical to the majority of molecular Schwartz has advocated for a number of pretation, as we regularly publish papers anthropologists and systematists, we years (developed in detail in his book The presenting strongly contrasting perspec- believe that the progress of scientific red ape: orangutans and human origins; tives on evolutionary biogeography. discourse is served by providing the Schwartz, 2005). Grehan and Schwartz’s We have chosen to comment on the advocates of this minority view an conclusions in the Journal of Biogeography paper by Grehan and Schwartz not simply opportunity to present all of their evidence paper are based on four cladistic analyses of because it comes from this minority per- and assumptions – only then can the up to 64 morphological characters, each spective but because it comments on a scientific community respond in an analysis comprised of a different array of topic of such keen general interest and informed manner.

ª 2009 Blackwell Publishing Ltd www.blackwellpublishing.com/jbi 1 doi:10.1111/j.1365-2699.2009.02172.x Editorial

1 Brett R. Riddle *and Grehan, J.R. & Schwartz, J.H. (2009) Evo- REFERENCES Robert J. Whittaker2 lution of the second orangutan: phylo-

1 Dawkins, R. (2004) The ancestor’s tale: geny and biogeography of hominid School of Life Sciences, a pilgrimage to the dawn of evolution. origins. Journal of Biogeography, doi: University of Las Vegas, Houghton Mifflin, Boston, MA. 10.1111/j.1365-2699.2009.02141.x. 4505 Maryland Parkway, Diamond, J. (1992) The third chimpanzee: Schwartz, J.H. (2005) The red ape: orangutans Las Vegas, NV, USA the evolution and future of the human and human origins, revised and updated. 2 and School of Geography animal. HarperCollins, New York. Westview Press, Cambridge, MA. and the Environment, Oxford University, South Parks Road, Oxford, OX1 3QY, UK *E-mail: [email protected]

2 Journal of Biogeography ª 2009 Blackwell Publishing Ltd