The Taphonomy and Paleoenvironmental Implications of the Laetoli Micromammals

Chapter

Abstract

Recent fieldwork conducted between 1998 and 2005 significantly increased the sample of fossil rodent specimens from Laetoli, Tanzania, the type locality of Australopithecus afarensis and this allowed the identification of several new micromammal species. This chapter discusses the taphonomy and paleoenvironmental implications of the Laetoli rodents. The taphonomic analysis of the new material looks at element representation, breakage patterns and bone surface modification and finds evidence of predator activity and weathering. In terms of paleoenvironment, the Upper Laetolil Beds assemblage has a very low abundance of murine rodents, a predominantly arboreal taxon (Thallomys) alongside an arboreal sciurid (Paraxerus), and several fossorial and burrowing taxa, which we interpret to indicate the presence of acacia trees growing on loose, well-drained sediments in a semi-arid environment. The Upper Ndolanya Beds sample remains small, and the species preserved are the same as those found in the Upper Laetolil Beds, with the exception of Thryonomys. This provides tentative evidence for a more mesic local environment in Upper Ndolanya times relative to the Upper Laetolil Beds.

Keywords

Pliocene Rodents Paleoenvironments Weathering Breakage patterns Bone surface modification 

References

  1. Agresti, A. (2007). An introduction to categorical data analysis. Hoboken: Wiley.CrossRefGoogle Scholar
  2. Alemseged, Z., Bobe, R., & Geraads, D. (2007). Comparability of fossil data and its significance for the interpretation of hominin environments: A case study in the Lower Omo Valley, Ethiopia. In Hominin environments in the East African Pliocene: An assessment of the faunal evidence (pp. 159–181). Dordrecht: Springer.CrossRefGoogle Scholar
  3. Andrews, P. (1989). Palaeoecology of Laetoli. Journal of Human Evolution, 18, 173–181.CrossRefGoogle Scholar
  4. Andrews, P. (1990). Owls, caves, and fossils. London: Natural History Museum.Google Scholar
  5. Baker, B. W., & Shaffer, B. S. (1999). Assumptions about species: A case study of tortoise bones from SE Texas. Journal of Field Archaeology, 26, 69–74.CrossRefGoogle Scholar
  6. Behrensmeyer, A. (1978). Taphonomic and ecologic information from bone weathering. Paleobiology, 4, 150–162.Google Scholar
  7. Behrensmeyer, A. K., & Hook, R. W. (1992). Paleoenvironmental ­contexts and taphonomic modes. In A. K. Behrensmeyer, J. D. Damuth, W. A. DiMichele, R. Potts, H.-D. Sues, & S. L. Wing (Eds.), Evolutionary paleoecology of terrestrial plants and animals (pp. 15–136). Chicago: University of Chicago Press.Google Scholar
  8. Belsky, A. (1990). Tree/grass ratios in East African savannas: A comparison of existing models. Journal of Biogeography, 17, 483–489.CrossRefGoogle Scholar
  9. 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
  10. Brett, R. A. (1991). The population structure of naked mole-rat ­colonies. In P. W. Sherman, J. U. M. Jarvis, & R. D. Alexander (Eds.), The biology of the naked mole-rat (pp. 97–136). Princeton: Princeton University Press.Google Scholar
  11. Davies, C. (1987). Fossil Pedetidae (Rodentia) from Laetoli. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 171–189). Oxford: Clarendon.Google Scholar
  12. De Graaff, G. (1981). The rodents of Southern Africa. Durban: Butterworth.Google Scholar
  13. Denys, C. (1983). Les rongeurs du Pliocene de Laetoli (Tanzania): Evolution, paléoecologie et paléobiogeographie. Approche qualitative et quantitative. Ph.D. disseration, University Pierre et Marie Curie, Paris.Google Scholar
  14. Denys, C. (1985a). Palaeoenvironmental and palaeobiogeographical significance of the fossil rodent assemblages of Laetoli (Pliocene, Tanzania). Palaeogeography, Palaeoclimatology, Palaeoecology, 52, 77–97.CrossRefGoogle Scholar
  15. Denys, C. (1985b). Laetoli: A Pliocene southern savanna fauna in the Eastern Rift Valley (Tanzania). Ecological and zoogeographical implications. In K. L. Schuchman (Ed.), Proceedings of the international symposium on African vertebrates (pp. 31–35). Bonn: Koenig.Google Scholar
  16. Denys, C. (1986). Le gisement Pliocène de Laetoli (Tanzanie, Afrique de l’Est): Analyse taphonomique des assemblages de microvertébrés. Palaeontographica Abteilung A-Palaozoologie-Stratigraphie, 194, 69–98.Google Scholar
  17. Denys, C. (1987). Fossil rodents (other than Pedetidae) from Laetoli. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 118–170). Oxford: Clarendon.Google Scholar
  18. Denys, C. (1999). Of mice and men. In T. Bromage & F. Schrenk (Eds.), African biogeography, climate change, and early hominid evolution (pp. 226–252). Oxford: Oxford University Press.Google Scholar
  19. Denys, C. (2011). Rodents. In T. Harrison (Ed.), Paleontology and ­geology of Laetoli: Human evolution in context (Fossil hominins and the associated fauna, vol. 2, pp. 15–53). Dordrecht: Springer.Google Scholar
  20. deWit, H. A., & Jeronimus, O. D. (1977). Soil map of the Serengeti plains. Wageningen: Wageningen Agricultural University.Google Scholar
  21. Earl, Z., & Nel, J. A. J. (1976). Climbing behaviour in three African rodent species. Zoologica Africana, 11, 183–192.Google Scholar
  22. Eck, G. G. (2007). The effects of collection strategy and effort on faunal recovery: A case study of the American and French collections from the Shungura Formation, Ethiopia. In R. Bobe, Z. Alemseged, & A. K. Behrensmeyer (Eds.), Hominin environments in the East African Pliocene: An assessment of the faunal evidence (pp. 183–215). Dordrecht: Springer.CrossRefGoogle Scholar
  23. Ellison, G. T. H. (1993). Group size, burrow structure and hoarding activity of pouched mice (Saccostomus campestris: Cricetidae) in Southern Africa. African Journal of Ecology, 31, 135–155.CrossRefGoogle Scholar
  24. Fernandez-Jalvo, Y., & Andrews, P. (1992). Small mammal taphonomy of Gran Dolina, Atapuerca (Burgos), Spain. Journal of Archaeological Science, 19, 407–428.CrossRefGoogle Scholar
  25. Fernandez-Jalvo, Y., Denys, C., Andrews, P., Williams, T., Dauphin, Y., & Humphrey, L. (1998). Taphonomy and palaeoecology of Olduvai Bed I (Pleistocene, Tanzania). Journal of Human Evolution, 34, 137–172.CrossRefGoogle Scholar
  26. Gentry, A. W. (1987). Pliocene Bovidae from Laetoli. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 378–408). Oxford: Clarendon.Google Scholar
  27. 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
  28. Hubert, B. (1978). Revision of the genus Saccostomus (Rodentia, Cricetomyinae), with new morphological and chromosomal data from specimens from the Lower Omo Valley, Ethiopia. Bulletin of the Carnegie Museum of Natural History, 6, 48–52.Google Scholar
  29. Jacobs, D. S., & Jarvis, J. U. M. (1996). No evidence for the work-conflict hypothesis in the eusocial naked mole-rat (Heterocephalus glaber). Behavioral Ecology and Sociobiology, 39, 401–409.CrossRefGoogle Scholar
  30. Jager, T., 1982. Soils of the Serengeti woodlands, Tanzania. Ph.D. dissertation, Agricultural University, Wageningen.Google Scholar
  31. Jarvis, J. U. M., & Bennett, N. C. (1991). Ecology and behavior of the family Bathyergidae. In P. W. Sherman, P. W. Jarvis, & R. D. Alexander (Eds.), The biology of the naked mole-rat (pp. 66–96). Princeton: Princeton University Press.Google Scholar
  32. Laden, G., & Wrangham, R. (2005). The rise of the hominids as an adaptive shift in fallback foods: Plant underground storage organs (USOs) and australopith origins. Journal of Human Evolution, 29, 482–498.CrossRefGoogle Scholar
  33. Leakey, M. D. (1987). Introduction. In M. D. Leakey & J. M. Harris (Eds.), Laetoli: A Pliocene site in northern Tanzania (pp. 1–22). Oxford: Clarendon.Google Scholar
  34. Linzey, A. V., & Kesner, M. H. (1997). Small mammals of a woodland-savannah ecosystem in Zimbabwe. I. Density and habitat occupancy patterns. Journal of Zoology, London, 243, 137–152.CrossRefGoogle Scholar
  35. Peters, C. R., Blumenschine, R. J., Hay, R. L., Livingstone, D. A., Marean, C. W., Harrison, T., Armour-Chelu, M., Andrews, P., Bernor, R. L., Bonnefiller, R., & Werdelin, L. (2008). Paleoecology of the Serengeti-Mara ecosystem. In A. R. E. Sinclair, C. Packer, S. A. R. Mduma, & J. M. Fryxell (Eds.), Serengeti III: Human impacts on ecosystem dynamics (pp. 47–94). Chicago: University of Chicago Press.CrossRefGoogle Scholar
  36. Reed, K. E. (1997). Early hominid evolution and ecological change through the African Plio-Pleistocene. Journal of Human Evolution, 32, 289–322.CrossRefGoogle Scholar
  37. Reed, D. N. (2005). Taphonomic implications of roosting behavior and trophic habits in two species of African Owl. Journal of Archaeological Science, 32, 1669–1676.CrossRefGoogle Scholar
  38. Reed, D. N. (2007). Serengeti micromammals and their implications for Olduvai paleoenvironments. In R. Bobe, Z. Alemseged, & A. K. Behrenesmeyer (Eds.), Hominin environments in the East African Pliocene: An assessment of the faunal evidence (pp. 217–255). Dordrecht: Springer.CrossRefGoogle Scholar
  39. Reed, D. N. (2011). Serengeti micromammal communities and the paleoecology of Laetoli, Tanzania. In T. Harrison (Ed.), Paleontology and geology of Laetoli: Human evolution in context (Geology, geochronology, paleoecology, and paleoenvironment, vol. 1, pp. 253–263). Dordrecht: Springer.Google Scholar
  40. Reed, D. N., Anderson, T. M., Dempewolf, J., Metzger, K., & Serneels, S. (2009). The spatial distribution of vegetation types in the Serengeti ecosystem: The influence of rainfall and topographic relief on vegetation patch characteristics. Journal of Biogeography, 36, 770–782.CrossRefGoogle Scholar
  41. Sénégas, F. (2004). A new species of Petromus (Rodentia, Hystricognatha, Petromuridae) from the Early Pliocene of South Africa and its paleoenvironmental implications. Journal of Vertebrate Paleontology, 24, 757–763.CrossRefGoogle Scholar
  42. Soligo, C., & Andrews, P. (2005). Taphonomic bias, taxonomic bias and historical non-equivalence of faunal structure in early hominin localities. Journal of Human Evolution, 49, 206–229.CrossRefGoogle Scholar
  43. Stahl, P. (1996). The recovery and interpretation of microvertebrate bone assemblages from archaeological contexts. Journal of Archaeological Method and Theory, 3, 31–75.CrossRefGoogle Scholar
  44. Su, D., & 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. Behrenesmeyer (Eds.), Hominin environments in the East African Pliocene: An assessment of the faunal evidence (pp. 279–313). Dordrecht: Springer.CrossRefGoogle Scholar
  45. 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
  46. White, T. D. (1998). The comparative biology of “Robust” Australopithecus: Clues from context. In F. E. Grine (Ed.), Evolutionary history of the “Robust” australopithecines (pp. 449–483). New York: Gruyter.Google Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Department of AnthropologyUniversity of Texas at AustinAustinUSA
  2. 2.Department of Systematics and Evolution – CP51UMR7205 CNRS: Origine structure & évolution de la Biodiversité, MNHNParisFrance

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