THE TAPHONOMY AND PALEOECOLOGY OF PLIO-PLEISTOCENE VERTEBRATE ASSEMBLAGES EAST OF LAKE RUDOLF, KENYA ANNA K. BEHRENSMEYER' CONTENTS Abstract 474 Introduction 474 The Taphonomy of Macro-Vertebrate Assemblages — 476 Factors Relating to Mode of Death 476 Factors Relating to Weathering and Decomposition -479 Transport and Burial 480 Diagenetic Factors 482 Conclusions 482 Characteristics of Recent Bones as Sedi-mentary Particles -483 Properties of Bones as Sedimentary Particles 485 Measurements of Bone Size and Density 485 Relative Dispersal Potential of Bones -_ 488 The Hydraulic Equivalence of Bones and Quartz Grains 490 Experiments in Bone-settling Velocities 492 The Hydraulic Equivalents of Fossil Bones 493 Current Velocities and Bone Transport 495 Additional Factors Affecting Bone Transport in Natural Situations 497 Bottom Morphology and Current Profile 498 Fluid Densitv 498 Burial Potential 498 Conclusions: Bones as Sedimentary Particles 499 Sedimentary Environments of the Koobi Fora Formation, East Rudolf 500 Geologic Setting 500 Regional Stratigraphy 503 RecLMit Limnology 505 Stratigraphy of tlie Koobi Fora Formation 507 Sedimentary Environments of the Fossil Vertebrate Localities 509 Designation of Sampling Localities 509 Method of Geologic Analysis 509 ^ Department of Paleontology, University of California, Berkeley, California 94720 Sedimentary Environments of the Sample Localities 514 Discussion and Conclusions 525 Sorting in Bone Assemblages of the Koobi Fora Formation 526 Sampling of Bone Assemblages 526 Choosing the Sample Areas 527 Sample Size 528 Method of Representing Fossil Abundance 528 Characteristics of the Bone Assemblages 529 Identification of Bones 530 Significance of the Frequency Data 531 Comparisons of Overall Bone Concentrations — 531 Relative Abundance of Skeletal Parts 532 Correlations Based on Bone Abundance 532 Factor Analysis of the Bone Assemblages 534 Comparisons with Voorhies Groups 536 Single Skeleton Comparisons 536 Discussion of Evidence for Transport Sorting 537 Additional Aspects of the Bone Assemblages 538 The Reptilian Assemblages 540 Conclusions Concerning the Bone Assemblages 540 Faunal Assemblages of the Koobi Fora Formation 541 Method of Identification 541 Abundance of Vertebrate Classes 542 Reptiles 543 Mammals — -545 Discussion of the Most Abundant Mammalian Groups 547 Abundances of Selected Mammalian Groups -549 Suids -, 549 Equids _ -551 Bovids -551 Hippos -552 Conclusions Regarding the Faunal Assemblages 553 Bull. Mus. Comp. Zool., 146(10): 473-578, February, 1975 473
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