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Stable Isotopic Analyses of Laetoli Fossil Herbivores

  • John D. KingstonEmail author
Chapter
Part of the Vertebrate Paleobiology and Paleoanthropology Series book series (VERT)

Abstract

In order to further refine early hominin paleoecology at Laetoli, over 500 specimens of fossil enamel and ostrich eggshell fragments collected from the Laetolil Beds and the Upper Ndolanya Beds were analyzed isotopically. The goal was to develop a high-resolution spatio-temporal framework for identifying and characterizing foraging patterns of mammalian herbivore lineages and fossil ostriches that could be used to investigate aspects of plant physiognomy and climate through the Laetoli succession. In general, dietary patterns at Laetoli suggest heterogeneous ecosystems with both C3 and C4 dietary plants available that could support grassland, woodland, and forested communities. All large-bodied mammalian herbivores analyzed yielded dietary signatures indicating mixed grazing/browsing strategies or exclusive reliance on C3 browse, more consistent with wooded than grassland-savanna biomes. Although there were no obvious uniform dietary shifts within specific mammalian herbivore groups in the sequence, the transition from the Upper Laetolil Beds to the Upper Ndolanya Beds documents a significant increase in the representation of grazing bovids. Relative to extant taxa in related lineages, the isotopic ranges of a number of Laetoli fossil herbivores are anomalous, indicating significantly more generalized intermediate C3/C4 feeding behaviors, perhaps indicative of dietary niches and habitat types with no close modern analogs. Diets of ostriches as reflected in the isotopic composition of eggshell components indicate predominantly C3 diets but with discrete isotopic shifts within the sequence linked to taxonomic and possibly environmental change.

Keywords

Isotopes Enamel Ostrich eggshells Paleodiet • Paleoecology Pliocene Tanzania Hominin 

Notes

Acknowledgements

I thank Terry Harrison for the opportunity to ­participate in research conducted by the Eyasi Plateau Paleontological and Geological Project. The following project members contributed to the recovery of the fossil material analyzed here: P. Abwalo, P. Andrews, E. Baker, M. Bamford, R. Chami, S. Cooke, P. Ditchfield, M. Duru, C. Feibel, T.S. Harrison, T. Harrison, S. Hixson, K. Kovarovic, A. Kweka, M. Lilombero, M.L. Mbago, K. McNulty, C. Msuya, S. Odunga, C. Robinson, L. Rossouw, W.J. Sanders, L. Scott, D. Su, M. Tallman, and S. Worthington. I thank the Tanzania Commission for Science and Technology and the Unit of Antiquities in Dar es Salaam for permission to conduct research in Tanzania. Special thanks go to N. Kayombo (Director General), P. Msemwa (Director), Amandus Kweka and all of the curators and staff at the National Museum of Tanzania in Dar es Salaam and Arusha for their support and assistance. Fieldwork at Laetoli and isotopic analyses were supported by grants from National Geographic Society, the Leakey Foundation, and NSF (Grants BCS-9903434 and BCS-0309513). Matt Sponheimer and an anonymous reviewer provided comments and suggestions that improved the manuscript.

References

  1. Andrews, P. J. (1989). Palaeoecology of Laetoli. Journal of Human Evolution, 18, 173–181.CrossRefGoogle Scholar
  2. Andrews, P. (2006). Taphonomic effects of faunal impoverishment and faunal mixing. Palaeogeography, Palaeoclimatology, Palaeoecology, 241, 572–589.CrossRefGoogle Scholar
  3. Andrews, P., & Bamford, M. (2008). Past and present vegetation ecology of Laetoli, Tanzania. Journal of Human Evolution, 54, 78–98.CrossRefGoogle Scholar
  4. Andrews, P., Bamford, M. K., Njau, E. F., & Leliyo, F. (2011). The ecology and biogeography of the Endulen-Laetoli area in northern Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 167–200). Dordrecht: Springer.Google Scholar
  5. Bamford, M. K. (2011). Fossil wood. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 217–233). Dordrecht: Springer.Google Scholar
  6. Behrensmeyer, A. K., & Hook, R. W. (1992). Paleoenvironmental contexts and taphonomic modes. In A. K. Beherensmeyer, J. D. Damuth, W. A. DiMichele, R. Potts, J. Sues, & S. L. Wing (Eds.), Terrestrial ecosystems through time: Evolutionary paleoecology of terrestrial plants and animals (pp. 15–136). Chicago: University of Chicago Press.Google Scholar
  7. Bishop, L. C., Hill, A., & Kingston, J. D. (1999). Paleoecology of Suidae from the Tugen Hills, Baringo, Kenya. In P. Andrews & P. Banham (Eds.), Late Cenozoic environments and hominid evolution: A tribute to Bill Bishop (pp. 99–112). London: Geological Society of London.Google Scholar
  8. Bonnefille, R., & Riollet, G. (1987). Palynological spectra from the Upper Laetolil Beds. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 52–61). Oxford: Clarendon.Google Scholar
  9. Boom, A., Marchant, R. A., Hooghiemstra, H., & Damste, J. S. S. (2002). CO2 and temperature-controlled altitudinal shifts of C4- and C3-dominated grasslands allows reconstruction of ρCO2. Palaeogeography, Palaeoclimatology, Palaeoecology, 177, 29–45.CrossRefGoogle Scholar
  10. Carroll, R. L. (1988). Vertebrate paleontology and evolution. San Francisco: Freeman.Google Scholar
  11. Caswell, H., Reed, R., Stephenson, S. N., & Werner, P. A. (1973). Photosynthetic pathways and selective herbivory: A hypothesis. The American Naturalist, 107, 465–480.CrossRefGoogle Scholar
  12. Cerling, T. E., Harris, J. M., MacFadden, B. J., Leakey, M. G., Quade, J., Eisenmann, V., & Ehleringer, J. R. (1997). Global vegetation change through the Miocene/Pliocene boundary. Nature, 389, 153–158.CrossRefGoogle Scholar
  13. Cerling, T. E., Harris, J. M., & Leakey, M. G. (1999). Browsing and grazing in elephants: The isotope record of modern and fossil proboscideans. Oecologia, 120, 360–374.Google Scholar
  14. Cerling, T. E., Harris, J. M., & Passey, B. H. (2003). Diets of East African Bovidae based on stable isotope analysis. Journal of Mammalogy, 84, 45–470.CrossRefGoogle Scholar
  15. Cerling, T. E., Hart, J. A., & Hart, T. B. (2004). Stable isotope ecology in the Ituri Forest. Oecologia, 138, 5–12.CrossRefGoogle Scholar
  16. Chapman, G. P. (1996). The biology of grasses. Wallingford: CAB International.Google Scholar
  17. Clarke, S. J., Miller, G. H., Fogel, M. L., Chivas, A. R., & Murray-Wallace, C. V. (2006). The amino acid and stable isotope biogeochemistry of elephant bird (Aepyornis) eggshells from southern Madagascar. Quaternary Science Reviews, 25, 2343–2356.CrossRefGoogle Scholar
  18. Codron, D., Luty, J., Lee-Thorp, J. A., Sponheimer, M., de Ruiter, D., & Codron, J. (2005). Utilization of savanna-based resources by Plio-Pleistocene baboons. South African Journal of Science, 101, 245–248.Google Scholar
  19. Codron, S., Lee-Thorp, J. A., Sponheimer, M., de Ruiter, D., & Codron, J. (2006). Inter- and Intrahabitat dietary variability of chacma baboons (Papio ursinus) in South African savannas based on fecal δ13C, δ15N, and %N. American Journal of Physical Anthropology, 129, 204–214.CrossRefGoogle Scholar
  20. Collatz, G. J., Berry, J. A., & Clark, J. S. (1998). Effects on climate and atmospheric CO2 partial pressure on the global distribution of C4 grassland: Past, present, and future. Oecologia, 114, 441–454.CrossRefGoogle Scholar
  21. Cooke, H. B. S. (1985). Plio-Pleistocene Suidae in relation to African hominid deposits. In Y. Coppens (Ed.), L’Environments des hominides au Plio-Pleistocene (pp. 101–117). Paris: Masson.Google Scholar
  22. Cooke, H. B. S., & Wilkinson, Q. F. (1978). Suidae and Tayassuidae. In V. J. Maglio & H. B. S. Cooke (Eds.), Evolution of African mammals (pp. 435–482). Cambridge: Harvard University Press.Google Scholar
  23. Deino, A. L. (2011). 40Ar/39Ar dating of Laetoli, Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 77–97). Dordrecht: Springer.Google Scholar
  24. Demment, M. W., & van Soest, P. J. (1985). A nutritional explanation for body-size patterns of ruminant and nonruminant herbivores. The American Naturalist, 125, 641–672.CrossRefGoogle Scholar
  25. Denys, C. (1987). Rodentia and Lagomorpha. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 118–170). Oxford: Clarendon.Google Scholar
  26. El-Zaatari, S., Grine, F. E., Teaford, M. F., & Smith, H. R. (2005). Molar microwear and dietary reconstruction of fossil Cercopithecoidea from the Plio-Pleistocene deposits of South Africa. Journal of Human Evolution, 49, 180–205.CrossRefGoogle Scholar
  27. Ferhi, A., & Letolle, R. (1977). Transpiration and evaporation as the principal factors in oxygen isotope variations of organic matter in land plants. Physiologie Végétale, 15, 363–370.Google Scholar
  28. Folinsbee, R. E., Fritz, P., Krouse, H. R., & Robblee, A. R. (1970). Carbon-13 and oxygen-18 in dinosaur, crocodile, and bird eggshells indicate environmental conditions. Nature, 168, 1353–1356.Google Scholar
  29. Fortelius, M., & Solounias, N. (2000). Functional characterization of ungulate molars using the Abrasion-Attrition wear gradient: A new method for reconstructing paleodiets. American Museum of Natural History Novitates, 3302, 1–36.CrossRefGoogle Scholar
  30. Gagnon, M., & Chew, A. E. (2000). Dietary preferences in extant African Bovidae. Journal of Mammalogy, 81, 490–511.CrossRefGoogle Scholar
  31. Gentry, A. W. (2011). Bovidae. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Fossil hominins and the associated fauna, vol. 2, pp. 363–465). Dordrecht: Springer.Google Scholar
  32. Gonfiantini, G. R., Gratziu, S., & Tongiorgi, E. (1965). Oxygen isotope composition of water in leaves. In Isotopes and radiation in soil-plant nutrition studies (pp. 405–410). Vienna: International Atomic Energy Agency.Google Scholar
  33. Grocke, D. R., Bocherens, H., & Mariotti, A. (1997). Annual rainfall and nitrogen-isotope correlation in macropod collagen: Application as a paleoprecipitation indicator. Earth and Planetary Science Letters, 153, 279–285.CrossRefGoogle Scholar
  34. Harris, J. M. (1983). Family Rhinocerotidae. In J. M. Harris (Ed.), Koobi Fora research project – The fossil ungulates: Proboscidea, Perissodactyla, and Suidae (pp. 130–155). Oxford: Clarendon.Google Scholar
  35. Harris, J. M. (1987). Fossil Suidae from Laetoli. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 349–358). Oxford: Clarendon.Google Scholar
  36. Harrison, T. (2011). Laetoli revisited: Renewed palaeontological and geological investigations at localities on the Eyasi Plateau in northern Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 1–15). Dordrecht: Springer.Google Scholar
  37. Harrison, T., & Msuya, C. P. (2005). Fossil struthionid eggshells from Laetoli, Tanzania: Taxonomic and biostratigraphic significance. Journal of African Earth Sciences, 41, 303–315.CrossRefGoogle Scholar
  38. Hay, R. L. (1987). Geology of the Laetoli area. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 23–47). Oxford: Clarendon.Google Scholar
  39. Heaton, T. H. E. (1987). The 15 N/14 N ratio of plants in South Africa and Namibia: Relationship to climate and coastal/saline environment. Oecologia, 74, 236–246.CrossRefGoogle Scholar
  40. Hernesniemi, E., Giaourtsakis, I., Evans, A., & Fortelius, M. (2011). Rhinocerotidae. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Fossil hominins and the associated fauna, vol. 2, pp. 275–293). Dordrecht: Springer.Google Scholar
  41. Hobson, K. A. (1995). Reconstruction avian diets using stable-carbon and nitrogen isotope analysis of egg components: Patterns of isotopic fractionation and turnover. The Condor, 97, 752–762.CrossRefGoogle Scholar
  42. Jacques, L., Ogle, N., Moussa, I., Kalin, R., Vignaud, P., Brunet, M., & Bocherens, H. (2008). Implications of diagenesis for the isotopic analysis of Upper Miocene large mammalian herbivore tooth enamel from Chad. Palaeogeography, Palaeoclimatology, Palaeoecology , 266 200–210.CrossRefGoogle Scholar
  43. Johnson, B. J. (1995) The stable isotope biogeochemistry of ostrich eggshell and its application to late Quaternary paleoenvironmental reconstructions in South Africa. Ph.D. dissertation. University of Colorado, Boulder.Google Scholar
  44. Johnson, B. J., Miller, G. H., Fogel, M. L., & Beaumont, P. B. (1997). The determination of late Quaternary paleoenvironments at Equus Cave, South Africa, using stable isotopes and amino acid racemization in ostrich eggshell. Palaeogeography, Palaeoclimatology, Palaeoecology, 136, 121–137.CrossRefGoogle Scholar
  45. Johnson, B. J., Fogel, M. L., & Miller, G. H. (1998). Stable isotopes in modern ostrich eggshell: A calibration for paleoenvironmental applications in semi-arid regions of southern Africa. Geochimica et Cosmochimica Acta, 62, 2451–2461.CrossRefGoogle Scholar
  46. Johnson, B. J., Miller, G. H., Fogel, M. L., Magee, J. W., Gagan, M. K., & Chivas, A. R. (1999). 65,000 Years of vegetation change in central Australia and the Australian summer monsoon. Science, 284, 1150–1152.CrossRefGoogle Scholar
  47. Kaiser, T. M. (2011). Feeding ecology and niche partitioning of the Laetoli ungulate faunas. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 329–354). Dordrecht: Springer.Google Scholar
  48. Kingston, J. D. (1999). Environmental determinants in early hominid evolution: Issues and evidence from the Tugen Hills, Kenya. In P. Andrews & P. Banham (Eds.), Late Cenozoic environments and hominid evolution: A tribute to Bill Bishop (pp. 69–84). London: Geological Society.Google Scholar
  49. Kingston, J. D., & Harrison, T. (2007). Isotopic dietary reconstructions of Pliocene herbivores at Laetoli: Implications for early hominin paleoecology. Palaeogeography, Palaeoclimatology, Palaeoecology, 243, 272–306.CrossRefGoogle Scholar
  50. Kohn, M. J., & Cerling, T. E. (2002). Stable isotope compositions of biological apatite. Reviews in Mineralogy and Geochemistry, 48, 455–488.CrossRefGoogle Scholar
  51. Kohn, M. J., Schoeninger, M. J., & Valley, J. W. (1996). Herbivore tooth oxygen isotope compositions: Effects of diet and physiology. Geochimica et Cosmochimica Acta, 60, 3889–3896.CrossRefGoogle Scholar
  52. Kohn, M., Schoeninger, M., & Barker, W. (1999). Altered states: Effects of diagenesis on fossil tooth chemistry. Geochimica et Cosmochimica Acta, 63, 2737–2747.CrossRefGoogle Scholar
  53. Kovarovic, K., & Andrews, P. (2007). A bovid postcranial ecomorphological survey of the Laetoli palaeoenvironment. Journal of Human Evolution, 52, 663–680.CrossRefGoogle Scholar
  54. Kovarovic, K., & Andrews, P. (2011). Environmental change within the Laetoli fossiliferous sequence: Vegetation catenas and bovid ecomorphology. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 367–380). Dordrecht: Springer.Google Scholar
  55. Kovarovic, K., Andrews, P., & Aiello, L. (2002). The palaeoecology of the Upper Ndolanya Beds at Laetoli, Tanzania. Journal of Human Evolution, 43, 395–418.CrossRefGoogle Scholar
  56. Kullmer, O. (1999). Evolution of African Plio-Pleistocene suids (Artiodactyla: Suidae) based on tooth pattern analysis. Kaupia, 9, 1–34.Google Scholar
  57. Leakey, M. D. (1987). Introduction. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 1–21). Oxford: Clarendon.Google Scholar
  58. Leakey, M. D., & Harris, J. M. (Eds.). (1987). Laetoli: A Pliocene site in northern Tanzania. Oxford: Clarendon.Google Scholar
  59. Lee-Thorp, J. A., Sealy, J. C., & van der Merwe, N. J. (1989a). Stable carbon isotope ratio differences between bone collagen and bone apatite, and their relationship to diet. Journal of Archaeological Science, 16, 585–599.CrossRefGoogle Scholar
  60. Lee-Thorp, J. A., van der Merwe, N. J., & Brain, C. K. (1989b). Isotopic evidence for dietary differences between two extinct baboon species from Swartkrans. Journal of Human Evolution, 18, 183–190.CrossRefGoogle Scholar
  61. Lee-Thorp, J. A., van der Merwe, N. J., & Brain, C. K. (1994). Diet of Australopithecus robustus at Swartkrans from stable carbon isotopic analysis. Journal of Human Evolution, 27, 361–372.CrossRefGoogle Scholar
  62. Levin, N. E., Cerling, T. E., Passey, B. H., Harris, J. M., & Ehleringer, J. R. (2006). A stable isotope aridity index for terrestrial environments. Proceedings of the National Academy of Sciences of the United States of America, 103, 11201–11205.CrossRefGoogle Scholar
  63. Levin, N. E., Simpson, S. W., Quade, J., Cerling, T. E., & Frost, S. R. (2008). Herbivore enamel carbon isotopic composition and the environmental context of Ardipithecus at Gona, Ethiopia. Geological Society of America Special Paper, 446, 215–234.Google Scholar
  64. Martin, C., Bentaleb, I., Kaandorp, R., Iacumin, P., & Chatri, K. (2008). Intra-tooth study of modern rhinoceros enamel δ18O: Is the difference between phosphate and carbonate δ18O a sound diagenetic test? Palaeogeography, Palaeoclimatology, Palaeoecology, 266, 183–189.CrossRefGoogle Scholar
  65. McNaughton, S. J., & Georgiadis, N. J. (1986). Ecology of African grazing and browsing mammals. Annual Review of Ecology and Systematics, 17, 39–66.CrossRefGoogle Scholar
  66. Mikhailov, K. E. (1992). The microstructure of avian and dinosaurian eggshell: Phylogenetic implications. In: K. E. Campbell, (Ed.), Papers in avian paleontology honoring Pierce Brodkorb, Science Series (pp. 361–373). Los Angeles: Natural History Museum of Los Angeles County.Google Scholar
  67. Murphy, B. P., & Bowman, D. M. J. S. (2006). Kangaroo metabolism does not cause the relationship between bone collagen δ15N and water availability. Functional Ecology, 20, 1062–1069.CrossRefGoogle Scholar
  68. Reed, K. E. (1997). Early hominid evolution and ecological change through the African Plio-Pleistocene. Journal of Human Evolution, 32, 289–322.CrossRefGoogle Scholar
  69. Robinson, C. (2011). Giraffidae. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Fossil hominins and the associated Fauna, vol. 2, pp. 339–362). Dordrecht: Springer.Google Scholar
  70. Rossouw, L., & Scott, L. (2011). Phytoliths and pollen, the microscopic plant remains in Pliocene volcanic sediments around Laetoli, Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 201–215). Dordrecht: Springer.Google Scholar
  71. Sage, R. F. (2004). The evolution of C4 photosynthesis. The New Phytologist, 161, 341–370.CrossRefGoogle Scholar
  72. Sauer, E. G. F. (1968). Calculations of struthious egg sizes from measurements of shell fragments and their correlation with phylogenetic aspects. Cimbebasia Series A, 1, 27–55.Google Scholar
  73. Sealy, J. C., van der Merwe, N. J., Thorp, J. A. L., & Lanham, J. L. (1987). Nitrogen isotopic ecology in southern Africa: Implications for environmental and dietary tracing. Geochimica et Cosmochimica Acta, 51, 2707–2717.CrossRefGoogle Scholar
  74. Segalen, L., Renard, M., Pickford, M., Senut, B., Cojan, I., Callonnec, L. L., & Rognon, P. (2002). Environmental and climatic evolution of the Namib Desert since the Middle Miocene: The contribution of carbon isotope ratios in ratite eggshells. Comptes Rendus Geoscience, 334, 917–924.CrossRefGoogle Scholar
  75. Sinclair, A. R. E. (1978). Factors affecting the food supply and breeding season of resident birds and movements of Palaearctic migrants in a tropical African savannah. Ibis, 120, 480–497.CrossRefGoogle Scholar
  76. Sponheimer, M., & Lee-Thorp, J. A. (2006). Enamel diagenesis at South African australopith sites: Implications for paleoecological reconstruction with trace element. Geochimica et Cosmochimica Acta, 70, 1644–1654.CrossRefGoogle Scholar
  77. Sponheimer, M., Reed, K., & Lee-Thorp, J. A. (2001). Isotopic plaeoecology of Makapansgat limeworks Perissodactyla. South African Journal of Science, 97, 327–329.Google Scholar
  78. Sponheimer, M., Lee-Thorp, J. A., DeRuiter, D. J., Smith, J. M., van der Merwe, N. J., Reed, K., Grant, C. C., Ayliffe, L. K., Robinson, T. F., Heidelberg, C., & Marcus, W. (2003). Diets of southern African Bovidae: Stable isotope evidence. Journal of Mammalogy, 84, 471–479.CrossRefGoogle Scholar
  79. Su, D. F. (2011). Large mammal evidence for the paleoenvironment of the Upper Laetolil and Upper Ndolanya Beds of Laetoli, Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology and paleoenvironment, vol. 1, pp. 381–392). Dordrecht: Springer.Google Scholar
  80. Su, D. F., & Harrison, T. (2007). The paleoecology of the Upper Laetolil Beds at Laetoli: A reconsideration of the large mammal evidence. In R. Bobe, Z. Alemseged, & A. K. Behrensmeyer (Eds.), Hominin environments in the East African Pliocene: An assessment of the faunal evidence (pp. 279–313). Dordrecht: Springer.CrossRefGoogle Scholar
  81. Su, D., & Harrison, T. (2008). Ecological implications of the relative rarity of fossil hominins at Laetoli. Journal of Human Evolution, 55, 672–681.CrossRefGoogle Scholar
  82. Tattersfield, P. (2011). Gastropoda. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Fossil hominins and the associated fauna, vol. 2, pp. 567–587). Dordrecht: Springer.Google Scholar
  83. Thornthwaite, C. W. (1948). An approach toward a rational classification of climate. Geographical Review, 38, 55–94.CrossRefGoogle Scholar
  84. Tieszen, L. L., Hein, D., Qvortrup, S. A., Troughtonn, J. H., & Imbama, S. K. (1979). Use of d13C values to determine vegetation selectivity in East African herbivores. Oecologia, 37, 351–359.CrossRefGoogle Scholar
  85. Tullett, S. G., & Board, R. G. (1977). Determinants of avian eggshell porosity. Journal of Zoology, 183, 203–211.CrossRefGoogle Scholar
  86. van der Merwe, N. J., Thackeray, J. F., Lee-Thorp, J. A., & Luyt, J. (2003). The carbon isotope ecology and diet of Australopithecus africanus at Sterkfontein, South Africa. Journal of Human Evolution, 44, 581–597.CrossRefGoogle Scholar
  87. Verdcourt, B. (1987). Mollusca from the Laetolil and Upper Ndolanya Beds. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 438–450). Oxford: Clarendon.Google Scholar
  88. Von Shirnding, Y., van der Merwe, N. J., & Vogel C. J. (1982). Influence of diet and age on carbon isotope ratios in ostrich eggshell. Archaeometry, 24, 3–20.CrossRefGoogle Scholar
  89. Walker, A. C. (1987). Fossil Galaginae from Laetoli. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 88–90). Oxford: Clarendon.Google Scholar
  90. White, T. D., Ambrose, S. H., Suwa, G., Su, D. F., DeGusta, D., Bernor, R. L., Boisserie, J. -R. Brunet, M., Delson, E., Frost, S. Garcia, N., Giaourtsakis, I. X., Haile-Selassie, Y., Howell, F. C., Wehmann, T., Likius, A., Pehlevan, C., Saegusa, H., Semprebon, G., Teaford, M., & Vrba, E. (2009). Macrovertebrate paleontology and the Pliocene habitat of Ardipithecus ramidus. Science, 326, 87–93.Google Scholar
  91. Zazzo, A., Bocherens, H., Brunet, M., Beauvilain, A., Billiou, D., Mackaye, H. T., Vignauch, P., & 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.CrossRefGoogle Scholar

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Authors and Affiliations

  1. 1.Department of AnthropologyEmory UniversityAtlantaUSA

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