The Implications of Disharmonious Assemblages for Pleistocene Extinctions*

Ernest L. Lundelius Jr


Department of Geological Sciences and Vertebrate Paleontology Laboratory, Texas Memorial Museum, University of Texas, Austin, Texas 78713, U.S.A.

The terms disharmonious or intermingled are applied to Pleistocene faunas that contain associations of species that are now allopatric. The apparently conflicting environmental implications of these faunas can be reconciled by postulating that the climate at the time these faunas existed was more equable than the present one. Associations of species of this kind are a ubiquitous feature of Pleistocene faunas in all parts of the world where adequate data are available. They imply a higher diversity of habitats which, in many instances, may be the result of the relatively greater control on the biota by locally more variable factors such as soils and topography. These associations have implications for the causes of the late Pleistocene extinctions in that their disappearance is coincident in time with the extinction event. The implication that these associations indicate a higher habitat diversity suggests that the extinction is linked to a reduction of habitat diversity at the end of the Pleistocene.