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Paleoecological reconstruction of a lower Pleistocene large mammal community using biogeochemical (δ13C, δ15N, δ18O, Sr:Zn) and ecomorphological approaches
Published online by Cambridge University Press: 08 April 2016
Abstract
Ecomorphological and biogeochemical (trace element, and carbon, nitrogen, and oxygen isotope ratios) analyses have been used for determining the dietary niches and habitat preferences of large mammals from lower Pleistocene deposits at Venta Micena (Guadix-Baza Basin, Spain). The combination of these two approaches takes advantage of the strengths and overcome the weakness of both approaches. The range of δ13Ccollagen values for ungulate species indicates that C3 plants were dominant in the diet of these mammals. δ13Ccollagen values vary among ungulates: perissodactyls have the lowest values and bovids the highest ones, with cervids showing intermediate values. The hypsodonty index measured in lower molar teeth and the relative length of the lower premolar tooth row indicate that the horse, Equus altidens, was a grazing species, whereas the rhino, Stephanorhinus etruscus, was a mixed feeder in open habitats. The similar δ13Ccollagen values shown in both perissodactyls does not reflect differences in feeding behavior with other ungulates, but rather a lower isotope enrichment factor in these monogastric herbivores than in ruminants, owing to their lower metabolic efficiency. The cervids Eucladoceros giulii and Dama sp. show low hypsodonty values, indicating that they were mixed feeders or browsers from forested habitats, an ecomorphologically based conclusion corroborated in the former by its low δ15Ncollagen content (canopy effect). Bovid species (Bovini aff. Leptobos, Soergelia minor, and Hemitragus albus) presumably inhabited open environments, according to their comparatively high hypsodonty and δ15Ncollagen values. Carnivore species (Homotherium latidens, Megantereon whitei, Pachycrocuta brevirostris, Canis falconeri, and Canis etruscus) exhibit higher δ15Ncollagen values than ungulates. These results record the isotopic enrichment expected with an increase in trophic level and are also supported by low bone Sr.Zn ratios. The elevated δ15Ncollagen value for a sample of Mammuthus meridionalis, which came from an individual with unfused epiphyses, confirms that it was a suckling animal. The δ15Ncollagen value of the scimitar-cat H. latidens is well above that obtained for the young individual of Mammuthus, which indicates that juvenile elephants were an important part of its diet. The hippo, Hippopotamus antiquus, yielded unexpectedly high δ15Ncollagen values, which suggest feeding on aquatic, non-N2-fixing plants. The high δ18Ohydroxyl values of bovids Hemitragus and Soergelia and of cervid Dama indicate that these ungulates obtained most of their water requirements from the vegetation. The megaherbivores and Eucladoceros exhibit the lowest δ18Ohydroxyl values, which suggest increased water dependence for them. Paleosynecological analysis was based on the relative abundance of species of large mammals from different ecological categories, determined by feeding behavior and locomotion types. The comparison of the frequencies of such categories in Venta Micena with those found in modern African communities indicates that the composition of the paleocommunity closely resembles those of savannas with tall grass and shrubs. The net above-ground primary productivity estimated for the on-crop biomass of the mammalian species preserved in the fossil assemblage also yields a figure congruent with that expected for an open environment.
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Literature Cited
Ambrose, S. H., and DeNiro, M. J. 1986a. Reconstruction of African human diet using bone collagen carbon and nitrogen isotope ratios. Nature 319:321–324.10.1038/319321a0Google Scholar
Ambrose, S. H., and DeNiro, M. J. 1986b. The isotopic ecology of East African mammals. Oecologia 69:395–406.Google Scholar
Andrews, P., Lord, J., and Nesbit-Evans, E. M. 1979. Patterns of ecological diversity in fossil and modern mammalian faunas. Biological Journal of the Linnean Society 11:177–205.Google Scholar
Anyonge, W. 1993. Body mass in large extant and extinct carnivores. Journal of Zoology 231:339–350.Google Scholar
Anyonge, W. 1996. Locomotor behaviour in Plio-Pleistocene sabretooth cats: a biomechanical analysis. Journal of Zoology 238:395–413.Google Scholar
Arribas, A., and Palmqvist, P. 1998. Taphonomy and paleoecology of an assemblage of large mammals: hyaenid activity in the lower Pleistocene site at Venta Micena (Orce, Guadix-Baza Basin, Granada, Spain). Geobios 31(Suppl.):3–47.Google Scholar
Anyonge, W. 1999. On the ecological connection between sabre-tooths and hominids: faunal dispersal events in the lower Pleistocene and a review of the evidence for the first human arrival in Europe. Journal of Archaeological Science 26:571–585.Google Scholar
Ayliffe, L. K., Lister, A. M., and Chivas, A. R. 1992. The preservation of glacial-interglacial climatic signatures in the oxygen isotopes of elephant skeletal phosphate. Palaeogeography, Palaeoclimatology, Palaeoecology 99:179–191.Google Scholar
Baiter, V., Person, A., Labourdette, N., Drucker, D., Renard, M., and Vandermeersch, B. 2001. Les Néandertaliens étaient-ils essentiellement carnivores? Résultats préliminaires sur les teneurs en Sr et Ba de la paléobiocenose mammalienne de Saint-Césaire. Comptes Rendus de l'Académie des Sciences, série II, 332:59–65.Google Scholar
Biknevicius, A. R., and Van Valkenburgh, B. 1996. Design for killing: craniodental adaptations of predators. Pp. 393–428in Gittleman, J. L., ed. Carnivore behavior, ecology, and evolution, Vol. 2. Cornell University Press, Ithaca, N.Y.Google Scholar
Biknevicius, A. R., Van Valkenburgh, B., and Walker, J. 1996. Incisor size and shape: implications for feeding behaviors in saber-toothed “cats.” Journal of Vertebrate Paleontology 16:510–521.Google Scholar
Bocherens, H., Koch, P. L., Mariotti, A., Geraads, D., and Jaeger, J. J. 1996. Isotopic biogeochemistry (13C, 18O) and mammalian enamel from African Pleistocene hominid sites. Palaios 11:306–318.Google Scholar
Bowen, H. J. M., and Dymond, J. A. 1955. Strontium and barium in plants and soils. Proceedings of the Royal Society of London B 144:355–368.Google Scholar
Braza, F., and Alvarez, F. 1987. Habitat use by red deer and fallow deer in Doñana National Park. Miscellània Zoològica 11:363–367.Google Scholar
Cerling, T. E., and Harris, J. M. 1999. Carbon isotope fractionation between diet and bioapatite in ungulate mammals and implications for ecological and paleoecological studies. Oecologia 120:337–363.Google Scholar
Cerling, T. E., and Sharp, Z. D. 1996. Stable carbon and oxygen isotope analysis of fossil tooth enamel using laser ablation. Palaeogeography, Palaeoclimatology, Palaeoecology 126:173–186.Google Scholar
Cerling, T. E., Harris, J. M., Ambrose, S. H., Leakey, M. G., and Solounias, N. 1997a. Dietary and environmental reconstruction with stable isotope analyses of herbivore tooth enamel from the Miocene locality of Fort Ternan, Kenya. Journal of Human Evolution 33:635–650.Google Scholar
Cerling, T. E., Harris, J. M., MacFadden, B. J., Leakey, M. G., Quade, J., Eisenmann, V., and Ehleringer, J. R. 1997b. Global vegetation change through the Miocene/Pliocene boundary. Nature 389:153–158.Google Scholar
Cerling, T. E., Harris, J. M., and Leakey, M. G. 1999. Browsing and grazing in elephants: the isotope record of modern and fossil proboscideans. Oecologia 120:364–374.Google Scholar
Collatz, G. J., Berry, J. A., and Clark, J. S. 1998. Effects of climate and atmospheric CO2 partial pressure on the global distribution of C4 grasses: present, past, and future. Oecologia 114:441–454.Google Scholar
Crutzen, P. J., Aslemann, I., and Seiler, W. 1986. Methane production by domestic animals, wild ruminants, and other herbivorous fauna, and humans. Tellus 38B:271–284.Google Scholar
Damuth, J. 1987. Interspecific allometry of population density in mammals and other animals: the independence of body mass and population energy use. Biological Journal of the Linnean Society 331:193–246.Google Scholar
Damuth, J., and MacFadden, B. J., eds. 1990. Body size in mammalian paleobiology: estimation and biological implications. Cambridge University Press, Cambridge.Google Scholar
DeNiro, M. J., and Epstein, S. 1978. Influence of diet on the distribution of carbon isotopes in animals. Geochimica et Cosmochimica Acta 42:495–506.Google Scholar
Edwards, G., and Walker, D. A. 1983. C3, C4: mechanisms, and cellular and environmental regulation, of photosynthesis. Blackwell Scientific, Oxford.Google Scholar
Ehleringer, J. R., Ceding, T. E., and Helliker, B. R. 1997. C4 photosynthesis, atmospheric CO2, and climate. Oecologia 112:285–299.Google Scholar
Elias, R., Hirao, Y., and Patterson, C. 1982. The circumvention of the natural biopurification of calcium along nutrient pathways by atmospheric inputs of industrial lead. Geochimica et Cosmochimica Acta 46:2561–2580.Google Scholar
Fariña, R. A. 1996. Trophic relationships among Lujanian mammals. Evolutionary Theory 11:125–134.Google Scholar
Feranec, R. S., and MacFadden, B. J. 2000. Evolution of the grazing niche in Pleistocene mammals from Florida: evidence from stable isotopes. Palaeogeography, Palaeoclimatology, Palaeoecology 162:155–169.10.1016/S0031-0182(00)00110-3Google Scholar
Fernández-Mosquera, D., Vila-Taboada, M., and Grandal-d'Anglade, A. 2001. Stable isotopes (δ13C, δ15N) from the cave bear (Ursus spelaeus): a new approach to its palaeoenvironment and dormancy. Proceedings of the Royal Society of London B 268:1159–1164.Google Scholar
Fortelius, M. 1985. Ungulate cheek teeth: developmental, functional, and evolutionary interrelations. Acta Zoologica Fennica 180:1–76.Google Scholar
Franz-Odendaal, T. A., Lee-Thorp, J. A., and Chinsamy, A. 2002. New evidence for the lack of C4 grassland expansions during the early Pliocene at Langebaanweg, South Africa. Paleobiology 28:378–388.Google Scholar
Freeman, K. H., and Colarusso, L. A. 2001. Molecular and isotopic records of C4 grassland expansion in the late Miocene. Geochimica et Cosmochimica Acta 65:1439–1454.Google Scholar
Gonyea, W. J. 1976. Behavioral implications of saber-toothed felid morphology. Paleobiology 2:332–342.10.1017/S0094837300004966Google Scholar
Gordon, I. J., and Illius, A. W. 1988. Incisor arcade structure and diet selection in ruminants. Functional Ecology 2:15–22.10.2307/2389455Google Scholar
Gröcke, D. R. 1997a. Stable-isotope studies on the collagen and hydroxylapatite components of fossils: palaeoecological implications. Lethaia 30:65–78.Google Scholar
Gröcke, D. R. 1997b. Distribution of C3 and C4 plants in the late Pleistocene of South Australia recorded by isotope biogeochemistry of collagen in megafauna. Australian Journal of Botany 45:607–617.Google Scholar
Gröcke, D. R. 1998. Carbon-isotope analyses of fossil plants as a chemostratigraphic and palaeoenvironmental tool. Lethaia 31:1–13.Google Scholar
Gröcke, D. R., and Bocherens, H. 1996. Isotopic investigation of an Australian island environment. Comptes Rendus de l'Académie des Sciences de Paris, série II, 322:713–719.Google Scholar
Gröcke, D. R., Bocherens, H., and Mariotti, A. 1997. Annual rainfall and nitrogen-isotope correlation in macropod collagen: application as a palaeoprecipitation indicator. Earth and Planetary Science Letters 153:279–285.Google Scholar
Grupe, G., and Krüger, H. H. 1990. Feeding ecology of the stone and pine marten revealed by element analysis of their skeletons. The Science of the Total Environment 90:227–240.Google Scholar
Guerrero-Alba, S., and Palmqvist, P. 1997. Estudio morfométrico del caballo de Venta Micena (Orce, Granada) y su comparación con los équidos modernos y del Plio-Pleistoceno de Europa y África. Paleontologia i Evolució 30–31:93–148.Google Scholar
Harris, J. M., and Cerling, T. E. 2002. Dietary adaptations of extant and Neogene African suids. Journal of Zoology 256:45–54.Google Scholar
Janis, C. M. 1976. The evolutionary strategy of the Equidae and the origins of rumen and cecal digestion. Evolution 30:757–774.Google Scholar
Janis, C. M. 1988. An estimation of tooth volume and hypsodonty indices in ungulate mammals, and the correlation of these factors with dietary preference. In Russell, D. E., Santoro, J. P., and Sigogneau, D., eds. Teeth revisited. Mémoires du Muséum National d'Histoire Naturelle C 53:367–387.Google Scholar
Janis, C. M. 1995. Correlations between craniodental morphology and feeding behaviour in ungulates: reciprocal illumination between living and fossil taxa. Pp. 76–98in Thomason, J. J., ed. Functional morphology in vertebrate paleontology. Cambridge University Press, Cambridge.Google Scholar
Janis, C. M., and Ehrhardt, D. 1988. Correlation of the relative muzzle width and relative incisor width with dietary preferences in ungulates. Zoological Journal of the Linnean Society 92:267–284.Google Scholar
Janis, C. M., Gordon, I. J., and Illius, A. W. 1994. Modelling equid/ruminant competition in the fossil record. Historical Biology 8:15–29.Google Scholar
Klepinger, L. L. 1984. Nutritional assessment from bone. Annual Review in Anthropology 13:75–96.Google Scholar
Klepinger, L. L., and Mintel, R. W. 1986. Metabolic considerations in reconstructing past diet from stable carbon isotope ratios of bone collagen. Pp. 43–48in Olin, J. G. and Black-man, M. J., eds. Proceedings of the 24th International Archaeometry Symposium. Smithsonian Institution Press, Washington, D.C.Google Scholar
Koch, P. L. 1998. Isotopic reconstruction of past continental environments. Annual Review of Earth and Planetary Sciences 26:573–613.Google Scholar
Kohn, M. J., Schoeninger, M. J., and Valley, J. W. 1996. Herbivore tooth oxygen isotope compositions: effects of diet and physiology. Geochimica et Cosmochimica Acta 60:3889–3896.Google Scholar
Kshirasagar, S. G., Lloyd, E., and Vaughen, J. 1966. Discrimination between strontium and calcium in bone and the transfer from blood to bone in the rabbit. British Journal of Radiology 39:131–140.Google Scholar
Lee-Thorp, J., and Van der Merwe, N. J. 1987. Carbon isotope analysis of fossil bone apatite. South African Journal of Science 83:712–715.Google Scholar
Lee-Thorp, J., Sealy, J. C., and Van der Merwe, N. J. 1989. Stable carbon isotope differences between bone collagen and bone apatite, and their relationship to diet. Journal of Archaeological Science 16:585–599.Google Scholar
Lewis, M. E. 1997. Carnivoran paleoguilds of Africa: implications for hominid food procurement strategies. Journal of Human Evolution 32:257–288.Google Scholar
MacFadden, B. J. 2000. Cenozoic mammalian herbivores from the Americas: reconstructing ancient diets and terrestrial communities. Annual Review of Ecology and Systematics 31:33–59.Google Scholar
MacFadden, B. J., and Cerling, T. E. 1996. Mammalian herbivore communities, ancient feeding ecology, and carbon isotopes: a 10-million-year sequence from the Neogene of Florida. Journal of Vertebrate Paleontology 16:103–115.Google Scholar
MacFadden, B. J., and Shockey, B. J. 1997. Ancient feeding ecology and niche differentiation of Pleistocene mammalian herbivores from Tarija, Bolivia: morphological and isotopic evidence. Paleobiology 23:77–100.Google Scholar
Marean, C. W., and Ehrhardt, C. L. 1995. Paleoanthropological and paleoecological implications of the taphonomy of a sabretooth's den. Journal of Human Evolution 29:515–547.Google Scholar
Martin, L. D., Babiarz, J. P., Naples, V. L., and Hearst, J. 2000. Three ways to be a saber-toothed cat. Naturwissenschaften 87:41–44.Google Scholar
Martínez-Navarro, B., and Palmqvist, P. 1996. Presence of the African saber-toothed felid Megantereon whitei (Broom 1937) (Mammalia, Carnivora, Machairodontidae) in Apollonia-1 (Mvgdonia basin, Macedonia, Greece). Journal of Archaeological Science 23:869–872.Google Scholar
Matheus, P. E. 1995. Diet and co-ecology of Pleistocene short-faced bears and brown bears in eastern Beringia. Quaternary Research 44:447–453.Google Scholar
McNab, B. K. 1980. Energetics and the limits to a temperate distribution in armadillos. Journal of Mammalogy 61:606–627.Google Scholar
McNaughton, S. J., Oesterheld, M., Frank, D. A., and Williams, K. J. 1989. Ecosystem-level patterns of primary productivity and herbivory in terrestrial habitats. Nature 341:142–144.Google Scholar
Mendoza, M., Janis, C. M., and Palmqvist, P. 2002. Characterizing complex craniodental patterns related to feeding behaviour in ungulates: a multivariate approach. Journal of Zoology 258:223–246.Google Scholar
Metges, C., Kempe, K., and Schmidt, H. L. 1990. Dependence of the carbon isotope contents of breath carbon dioxide, milk, serum and rumen fermentation products on the value of food in dairy cows. Brown Journal of Nutrition 63:187–196.Google Scholar
Minagawa, M., and Wada, E. 1984. Stepwise enrichment of 15N along food chains: further evidence and the relation between δ15N and animal age. Geochimica et Cosmochimica Acta 48:1135–1140.Google Scholar
Nedin, C. 1991. The dietary niche of the extinct Australian marsupial lion: Thylacoleo carnifex Owen. Lethaia 24:115–118.Google Scholar
Nelson, D. E., Angerbjörn, A., Lidén, K., and Turk, I. 1998. Stable isotopes and the metabolism of the European cave bear. Oecologia 116:177–181.Google Scholar
Novak, R. M. 1999. Walker's mammals of the world. Johns Hopkins University Press, Baltimore.Google Scholar
Ostrom, P. H., Zonneveld, J.-P., and Robbins, L. L. 1994. Organic geochemistry of hard parts: assessment of isotopic variability and indigeneity. Palaeogeography, Palaeoclimatology, Palaeoecology 107:201–212.Google Scholar
Palmqvist, P., and Arribas, A. 2001. Taphonomic decoding of the paleobiological information locked in a lower Pleistocene assemblage of large mammals. Paleobiology 27:512–530.Google Scholar
Palmqvist, P., Martínez-Navarro, B., and Arribas, A. 1996. Prey selection by terrestrial carnivores in a lower Pleistocene paleocommunity. Paleobiology 22:514–534.Google Scholar
Palmqvist, P., Arribas, A., and Martínez-Navarro, B. 1999. Ecomorphological analysis of large canids from the lower Pleistocene of southeastern Spain. Lethaia 32:75–88.Google Scholar
Palmqvist, P., Mendoza, M., Arribas, A., and Gröcke, D. R. 2002. Estimating the body mass of Pleistocene canids: discussion of some methodological problems and a new “taxon free” approach. Lethaia 35:358–360.Google Scholar
Pérez-Barbería, F. J., and Gordon, I. J. 2001. Relationships between oral morphology and feeding style in the Ungulata: a phylogenetically controlled evaluation. Proceedings of the Royal Society of London B 268:1021–1030.Google Scholar
Peters, R. H. 1983. The ecological implications of body size. Cambridge University Press, Cambridge.Google Scholar
Rawn-Schatzinger, V. 1992. The scimitar cat Homotherium serum Cope: osteology, functional morphology, and predatory behaviour. Illinois State Museum Reports of Investigations 47:1–80.Google Scholar
Reed, K. E. 1998. Using large mammal communities to examine ecological and taxonomic structure and predict vegetation in extant and extinct assemblages. Paleobiology 24:384–408.Google Scholar
Richards, M. P., Pettitt, P. B., Trinkaus, E., Smith, F. H., Paunovic, M., and Karavanic, I. 2000. Neanderthal diet at Vindija and Neanderthal predation: the evidence from stable isotopes. Proceedings of the National Academy of Sciences USA 97:7663–7666.Google Scholar
Robinson, D. 2001. δ15N as an integrator of the nitrogen cycle. Trends in Ecology and Evolution 16:153–162.Google Scholar
Rodière, E., Bocherens, H., Angibault, J. M., and Mariotti, A. 1996. Paticularités isotopiques de l'azote chez le chevreuil (Capreolus capreolus L.): implications pour les reconstitutions paléoenvironnementales. Comptes Rendus de l'Académie des Sciences, série II, 323:179–185.Google Scholar
Sagredo, R. 1987. Flora de Almería: plantas vasculares de la provincia. Instituto de Estudios Almerienses, Diputación Provincial de Almería, Spain.Google Scholar
Schoeninger, M. J. 1979. Diet and status at Chalcatzingo: some empirical and technical aspects of strontium analysis. American Journal of Physical Anthropology 51:295–309.Google Scholar
Schwarcz, H. P., Dupras, T. L., and Fairgrieve, S. I. 1999. 15N enrichment in the Sahara: in search of a global relationship. Journal of Archaeological Science 26:629–636.Google Scholar
Sealy, J. C., Van der Merwe, N. J., Lee Thorp, J. A., and Lanham, J. L. 1987. Nitrogen isotopic ecology in southern Africa: implications for environmental and dietary tracing. Geochimica et Cosmochimica Acta 51:2707–2717.Google Scholar
Sillen, A. 1986. Biogenic and diagenetic Sr/Ca in Plio-Pleistocene fossils of the Omo Shungura Formation. Paleobiology 12:311–323.Google Scholar
Sillen, A. 1992. Strontium-calcium ratios (Sr/Ca) of Australopithecus robustus and associated fauna from Swartkrans. Journal of Human Evolution 23:495–516.Google Scholar
Sillen, A., and Kavanagh, M. 1982. Strontium and paleodietary research. Yearbook of Physical Anthropology 25:67–90.Google Scholar
Sillen, A., and Lee-Thorp, J. A. 1994. Trace-element and isotopic aspects of predator-prey relationships in terrestrial foodwebs. Palaeogeography, Palaeoclimatology, Palaeoecology 107:243–255.Google Scholar
Smith, B. N., and Epstein, S. 1971. Two categories of 13C/12C ratios for higher plants. Plant Physiology 47:380–384.Google Scholar
Solounias, N., and Moelleken, S. M. C. 1993. Tooth microwear and premaxillary shape of an archaic antelope. Lethaia 26:261–268.Google Scholar
Spencer, L. M. 1995. Morphological correlates of dietary resource partitioning in the African Bovidae. Journal of Mammalogy 76:448–471.Google Scholar
Sponheimer, M., and Lee-Thorp, J. A. 1999a. The alteration of enamel carbonate environments during fossilization. Journal of Archaeological Science 26:143–150.Google Scholar
Sponheimer, M., and Lee-Thorp, J. A. 1999b. Isotopic evidence for the diet of an early hominid, Australopithecus africanus. Science 283:368–370.Google Scholar
Sponheimer, M., and Lee-Thorp, J. A. 2001. The oxygen isotope composition of mammalian enamel carbonate from Morea Estate, South Africa. Oecologia 126:153–157.Google Scholar
Sponheimer, M., Reed, K. E., and Lee-Thorp, J. A. 1999. Combining isotopic and ecomorphological data to refine bovid paleodietary reconstruction: a case study from the Makapansgat Limeworks hominin locality. Journal of Human Evolution 36:705–718.Google Scholar
Toots, H., and Voorhies, M. R. 1965. Strontium in fossil bones and the reconstruction of food chains. Science 149:854–855.Google Scholar
Torres, J. M., Borja, C., and García-Olivares, E. 2002. Immunoglobulin G in 1.6-million-year-old fossil bones from Venta Micena (Granada, Spain). Journal of Archaeological Science 29:167–175.Google Scholar
Turner, A., and Anton, M. 1996. The giant hyena, Pachycrocuta brevirostris (Mammalia, Carnivora, Hyaenidae). Geobios 29:455–468.Google Scholar
Van der Merwe, N. J. 1982. Carbon isotopes, photosynthesis, and archaeology. American Scientist 70:596–606.Google Scholar
Van Valkenburgh, B. 1985. Locomotor diversity within past and present guilds of large predatory mammals. Paleobiology 11:406–428.Google Scholar
Van Valkenburgh, B. 1987. Skeletal indicators of locomotor behavior in living and extinct carnivores. Journal of Vertebrate Paleontology 7:162–182.Google Scholar
Van Valkenburgh, B. 1988. Trophic diversity in past and present guilds of large predatory mammals. Paleobiology 14:155–173.Google Scholar
Van Valkenburgh, B. 1989. Carnivore dental adaptations and diet: a study of trophic diversity within guilds. Pp. 410–435in Gittleman, J. L., ed. Carnivore behavior, ecology, and evolution. Cornell University Press, Ithaca, N.Y.Google Scholar
Williams, S. H., and Kay, R. F. 2001. A comparative test for adaptive explanations for hypsodonty in ungulates and rodents. Journal of Mammalian Evolution 8:207–229.Google Scholar
Witt, C. B., and Ayliffe, L. K. 2001. Carbon isotope variability in the bone collagen of red kangaroos (Macropus rufus) is age dependent: implications for palaeodietary studies. Journal of Archaeological Science 28:247–252.Google Scholar
Wyckoff, R. W. 1972. The biochemistry of animal fossils. Scientechnica, Ltd., Bristol, England.Google Scholar
Wyckoff, R. W., and Doberenz, A. R. 1967. The strontium content of fossil teeth and bones. Geochimica et Cosmochimica Acta 32:109–115.Google Scholar
Zazzo, A., Bocherens, H., Brunet, M., Beauvilain, A., Billiou, D., Mackaye, H. T., Vignaud, P., and Mariotti, A. 2000. Herbivore paleodiet and paleoenvironmental changes in Chad during the Pliocene using stable isotope ratios of tooth enamel carbonate. Paleobiology 26:294–309.Google Scholar