Biogeochemical and Ecomorphological Inferences On Prey Selection and Resource Partitioning Among Mammalian Carnivores In An Early Pleistocene Community

Abstract

Biogeochemical (␦ 13 C, ␦ 15 N, and ␦ 18 O values) and ecomorphological analyses of the early Pleistocene fauna of Venta Micena (Orce, Guadix-Baza basin, SE Spain) provide interesting clues on the physiology, dietary regimes, habitat preferences, and ecological interactions of large mammals. Such inferences are useful in deciphering aspects of paleocommunity structure and predator-prey relationships. Specifically, the hypsodonty index combined with ␦ 13 C values allows classifying the ungulates among grazers from open habitat (Equus altidens, Bison sp., Praeovibos sp., Hemitragus albus, Hippopotamus antiquus, and Mammuthus meridionalis), mixed feeders (Soergelia minor and Pseudodama sp.), and browsers from canopy areas (Stephanorhinus sp. and Praemegaceros cf. verticornis). Given that ␦ 13 C values indicate that all these herbivores fed exclusively on C 3 plants, significant differences in isotopic values between perissodactyls (monogastric, hindgut fermenters) and ruminants (foregut fermenters) reflect differences in digestive efficiency. Values of ␦ 18 O indicate the dietary water source of ungulates, revealing that Pseudodama sp., Hemitragus albus, and Soergelia minor obtained a significant fraction of their metabolic water from vegetation. Carnivores show higher ␦ 15 N values than herbivores, which records the isotopic enrichment expected with an increase in trophic level. Hippopotamus antiquus and Praeovibos sp. have unexpectedly high ␦ 15 N values, suggesting that they predominantly consumed aquatic plants and lichens, respectively. Inferences on predator-prey relationships, derived from the use of linear mixing models, indicate resource partitioning among sympatric predators; saber-tooth Megantereon whitei and jaguar Panthera cf. gombaszoegensis were ambushers in closed habitat while saber-tooth Homotherium latidens and wild dog Lycaon lycaonoides were coursing predators in open plains. The giant hyena Pachycrocuta brevirostris scavenged the prey of these hypercarnivores. PALAIOS PALMQVIST ET AL.TABLE 2-Relative contributions (mean percentages of consumption and their standard deviations) of each of the nine ungulate prey species that are well represented in the Venta Micena assemblage to the diet of each of the four hypercarnivores, calculated in 5% increments with the software IsoSource (Phillips and Gregg, 2003; IsoSource, 2006). Prey-predatorHomotherium latidens Megantereon whitei Panthera cf. gombaszoegensis Lycaon lycaonoides Mammuthus meridionalis 12.9 Ϯ 12.3 0.7 Ϯ 1.8 1.8 Ϯ 3.0 8.5 Ϯ 8.9 Hippopotamus antiquus 7.9 Ϯ 5.9 0.5 Ϯ 1.5 0.0 Ϯ 0.0 2.6 Ϯ 3.6

Resource partitioning among top predators in a Miocene food web

“…d 13 C values of the mammals are used to estimate gradients from open to closed habitats within the original Miocene ecosystem. Compared with analyses of mammalian herbivores, stable isotope analyses of modern and Pleistocene carnivores are infrequent (although increasing; [20][21][22][23][24][25][26][27][28][29]). Cerro de los Batallones localities offer a view into carnivore guilds that is rarely available and, to the best of our knowledge, this study constitutes the first stable isotope analysis of mammalian predator-prey relationships for a Miocene fauna.…”

Discriminant function analyses in archaeology: are classification rates too good to be true?

“…The application of DFA is also a well-established practice with regard to faunal material where it is increasingly used to predict taxonomic affiliation, habitat preference, dietary group, body size or sex (e.g. Elton, 2001;Mendoza and Palmqvist, 2006;Kovarovic and Andrews, 2007;Palmqvist et al, 2008;Plummer et al, 2008;Germonpré et al, 2009;Sapir-Hen et al, 2009;Klein et al, 2010). The method is naturally comparative where data regarding modern fauna, for which the taxonomy and behaviour are known, provide the basis for making predictions about unknown or unclassified individuals, which are the fossil or archaeological specimens.…”

Were large carnivorans and great climatic shifts limiting factors for hominin dispersals? Evidence of the activity of Pachycrocuta brevirostris during the Mid-Pleistocene Revolution in the Vallparadís Section (Vallès-Penedès Basin, Iberian Peninsula)

“…3) is indicative of warm and humid conditions, as the extinct H. antiquus (closely related to the extant Hippopotamus amphibius) is unlikely to have tolerated very cold temperatures (leading to the seasonal freezing of the rivers they inhabited; Madurell-Malapeira et al, 2010;García-Aguilar et al, 2014. Moreover, this hippo species was more dependent of the aquatic environments than H. amphibious, as suggested by its huge size (3200 kg average mass) and shortened metapodials, as well as by biogeochemical analysis of bone collagen isotopes in Venta Micena, which show that H. antiquus fed on aquatic macrophytes instead of grazing on terrestrial grasses, as do the living hippos (Palmqvist et al, 2003(Palmqvist et al, , 2008a(Palmqvist et al, , 2008bGarcía-Aguilar et al, 2014. This suggests that H. antiquus could not have inhabited watercourses that froze in winter or desiccated in summer.…”