Modeling the Biogeography of Fossil Baboons

Abstract

We use a model of modern baboon socio-ecology to explore the behavioral ecology and biogeography of the extinct Plio-Pleistocene baboons (genera Parapapio, Gorgopithecus, Dinopithecus, and Papio). The model is based on the way climate affects the baboons' time budgets, and focuses on intersite variability in behavior rather than on species-typical patterns of behavior, as most previous approaches have done. We use climate estimates for individual fossil sites based on matching modern habitats using faunal profiles and estimates of individual species' body masses given in the literature. The model allows us to examine the minimum and maximum sizes of groups that individual species would have been able to support at particular localities, and hence the biogeography of a species on a continental scale. In doing so, the model allows us to examine which variables are most responsible for limiting a species' ecological and biogeographic flexibility, and through this to explore a species' capacity for coping with climate change. Feeding time is identified as the main constraint. In general, largebodied species would have had more difficulty surviving in as wide a range of habitats as smaller-bodied species, and this may explain the limited geographical distribution of large-bodied baboons such as Gorgopithecus and Dinopithecus.

Baboon phylogeny as inferred from complete mitochondrial genomes

“…The refined divergence dates among baboon mitochondrial lineages do not contradict the earlier hypothesis that the timing of divergence events among Papio lineages can be placed in a wider context related to changes in the African paleoclimate during the Pleistocene with recurrent expansions and retreats of the savanna biome as suitable habitat for baboons (Hamilton and Taylor,1991; deMenocal,1995, 2004; Maley,1996; Zinner et al,2009, 2011a, Bettridge and Dunbar,2012). Because of periodical climate changes and the isolation and reconnection of savanna habitats, populations of baboons changed in size and spatial distribution, perhaps cyclically.…”

“…In our reconstruction, P. ursinus South diverged first followed by the main southnorth split, but similarly possible are an initial southnorth split or a trifurcation within a relative short time period (mtDNA1: 2.21-1.99 Ma; mtDNA2: 1.96-1.76 Ma) among the lineages leading to P. ursinus South, the clade consisting of P. ursinus North, P. cynocephalus South and P. kindae, and the northern clade. The refined divergence dates among baboon mitochondrial lineages do not contradict the earlier hypothesis that the timing of divergence events among Papio lineages can be placed in a wider context related to changes in the African paleoclimate during the Pleistocene with recurrent expansions and retreats of the savanna biome as suitable habitat for baboons (Hamilton and Taylor, 1991;deMenocal, 1995deMenocal, , 2004Maley, 1996;Zinner et al, 2009, 2011a, Bettridge and Dunbar, 2012. Because of periodical climate changes and the isolation and reconnection of savanna habitats, populations of baboons changed in size and spatial distribution, perhaps cyclically.…”

New craniodental fossils of papionin monkeys from Cooper's D, South Africa

“…Like T. o. oswaldi , these large papionins go extinct by the middle Pleistocene. Bettridge and Dunbar () suggest that Gorgopithecus and Dinopithecus occupied a small geographical range due to their large body size, which requires a relatively narrow climate tolerance and longer feeding times. If this is the case, they would be more likely to go extinct during periods of climate variability.…”

Paleodistribution modeling in archaeology and paleoanthropology

“…An interesting example of a mechanistic distribution model directly relevant to paleoanthropology is one based on modern baboon socioecology and used to predict the distribution of extinct baboon species of different body sizes (Bettridge and Dunbar, 2012). This model addressed the effects of temperature and other aspects of climate on species ecophysiology, as have mechanistic SDMs (Buckley et al, 2010a), and then linked this to time budgets.…”