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Abstract

Recent discussions of correlations between global climatic change and evolution of the African Plio-Pleistocene biota have revealed apparent discrepancies between the timing and significance of events recorded in different data sets. The most notable differences have occurred in relation to a major shift in the ratio of marine oxygen isotopes by 2.5 myr and claims for a causally related transition in the biota. Vegetational changes recorded in palaeosol stable isotope values suggest that the major increase in more open vegetation occurs later -1.7 myr. We investigate the problem with particular reference to events at 1.7 myr and the African extinctions of machairodont cats that take place in their aftermath, since extinctions of such eurytopic taxa are likely to mark significant changes in conditions. We compare the pattem of such extinctions with those of similar or identical taxa in Eurasia and the New World, and suggest that a major environmental change is clearly indicated in each case. It is likely that the African vegetational changes recorded -1.7 myr represent a terrestrial response to global climatic changes recorded in marine core records -1.9 myr. Key words: Climate, evolution, Plio-Pleistocene, machairodont cats, extinction,I', Afi'ica, Europe. RESUMENEstudios recientes sobre las correlaciones entre cambios clim<'iticos globales y la evolucion de la biota del Plio-Pleistoceno Africano han revelado aparentes discrepancias entre las fechas y la significacion de eventos registrados en distintas fuentes. Las diferencias mas notables se refieren a un importante cambio en la proporcion de isotopos de oxfgeno marinas hace 2,5 millones de afios, y a la posibilidad de una transicion biotica relacionada causalmente con dicho cambio. Cambios en la vegetacion detectados a traves de los valores de isotopos estables en los paleosuelos sugieren que el principal cambio hacia una vegetacion mas abierta ocurrio mas tarde, hace 1,7 millones de afios. Nosotros estudiamos el problema refiriendonos en particular a los eventos de hace 1,7 millones de afios, y a la extincion en Africa de los felidos con dientes de sable que se produce poco despues, puesto que las extinciones de taxones euritopicos como estos probablemente sefiala cambios significativos en las condiciones ambientales. Nosotros comparamos el patron de dichas extinciones con los de taxones semejantes 0 identicos, en Eurasia y America, y sugerimos que en cada caso hay claros indicios de importantes cambios ambientales. Es probable que los cambios en la vegetacion de Africa registrados hace 1,7 millones de afios representen una respuesta en el medio terrestre alas cambios clim<'iticos globales reflejados en el registro marino hace 1,9 millones de afios.

The reorganization of predator–prey networks over 20 million years explains extinction patterns of mammalian carnivores

“…Because low prey diversity may limit the persistence of predator populations (Sandom et al, 2013;Turner & Antón, 1998), we used linear models to test if the longevity of predator species was associated with its mean degree and relative degree. We expected that predators that underwent reductions in their degree, and hence lost potential prey, would show shorter longevities.…”

The Influence of Image Salience on the Artistic Renditions of Cave Lions in the Early Upper Paleolithic

“…Emergency bipedal flight behavior with rapid assessment of potential refuge has arguably provided the most consistent context for selection to act on successful predator avoidance. It is reasonable to suggest that Megantereon provided one of the longest time frames of felid predation on hominins (Lee-Thorp, Thackery, & van der Merwe, 2000) prior to its extinction during the Early Pleistocene (Treves & Palmqvist, 2007;Turner & Antón, 1998;Werdelin & Lewis, 2005).…”