Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Hunter, J. P. Articles by Janis, C. M. Search for Related Content GeoRef GeoRef Citation

"Garden of Eden" or "Fool's Paradise"? Phylogeny, dispersal, and the southern continent hypothesis of placental mammal origins

¹ John P. Hunter. Department of Evolution, Ecology, and Organismal Biology, Ohio State University at Newark, 1179 University Drive, Newark, Ohio 43055. hunter.360@osu.edu
² Christine M. Janis. Department of Ecology and Evolutionary Biology, Box G-B207, Brown University, Providence, Rhode Island 02912. Christine_Janis@brown.edu

Accepted 30 November 2005

The first 20% of the full text of this article appears below.

Where did the modern lineages of placental mammals originate? Recent molecular data seemingly have overturned not only schemata of placental relationships based on morphological data, but also hypotheses about the time and place of origin of the modern lineages. The original hypothesis of Northern Hemisphere origin, based on the fossil record, has been replaced by a "Garden of Eden" hypothesis of origins on a southern continent, based on molecular phylogenies. But, do the molecular data really support this new view of placental mammal origins?

Recent molecular phylogenies have converged on the finding of two basal placental clades (Springer et al. 1997; Stanhope et al. 1998; Madsen et al. 2001; Murphy et al. 2001), Afrotheria and Xenarthra, each endemic to separate southern continents, and a third clade, Boreoeutheria, of apparent northern continent affinity (Murphy et al. 2001). This finding, in association with molecular divergence estimates starting in the mid Cretaceous (see Springer et al. 2003 for a recent synthesis), has been used to support a mid Cretaceous origin of placentals in Gondwana (Eizirik et al. 2001; Murphy et al. 2001). These divergence time estimates imply a radiation of the ordinal lineages starting 105 million years ago (Springer et al. 2003), millions of years prior to the appearance of undoubted crown placentals in the early Cenozoic (Foote et al. 1999; Novacek 1999; Meng et al. 2003; Wible et al. 2004; Asher et al. 2005).

A biogeographic scenario proposed to account for Gondwanan origins calls for vicariance, associated with mid-Cretaceous separation of Africa from South America, followed by later dispersal into the northern continents in the Late Cretaceous. This biogeographic scenario has been criticized on varied paleontological grounds (Ji et al. 2002; Archibald . . . [Full Text of this Article]

This article has been cited by other articles:

				W. J. Murphy, T. H. Pringle, T. A. Crider, M. S. Springer, and W. Miller Using genomic data to unravel the root of the placental mammal phylogeny Genome Res., April 1, 2007; 17(4): 413 - 421. [Abstract] [Full Text] [PDF]