East African Hominids Research Articles

The Evolution of neogene terrestrial ecosystems in Europe

1. Introduction J. Agusti, L. Rook and P. Andrews Part I. Palaeogeography of the Circum-Mediterranean Region: 2. Mediterranean and Paratethys palaeogeography during Oligocene and Miocene Fred Rogl 3. Pliocene tephra correlations between East African hominid localities, the Gulf of Aden and the Arabian Sea Peter B. deMenocal and Francis H. Brown 4. Climatic perspectives for neogene environmental reconstructions Eileen M. O'Brien and Charles R. Peters Part II. Miocene Mammalian Successions: 5. A critical re-evaluation of the Miocene mammals units in western Europe: dispersal events and the problems of correlation J. Agusti, L. Cabrera and M. Garces 6. Large mammals from the Vallesian of Spain Jorge Morales, Manuel Nieto, Meike Kholer and Salvador Moya-Sola 7. Trends in rodent assemblages from the Aragonian (Early-Middle Miocene) of the Calatayud-Daroca basin, Aragon, Spain R. Daams, A. J. van der Meulen, P. Pelaez-Campomanes and M. A. Alvarez-Sierra 8. The Late Miocene small mammal succession from France, with emphasis on the Rhone Valley localities Pierre Mein 9. Late Miocene mammals from central Europe Jens Lorenz Franzen and Gerharrd Storch 10. An overview on the Italian Miocene land mammal faunas Lorenzo Rook, Laura Abbazzi and Burkhart Engesser 11. The Miocene large mammal succession in Greece Louis de Bonis and George D. Koufos 12. Chronology and mammal faunas of the Miocene Sinap formation, Turkey Juha Pekka Lunkka, Mikael Fortelius, John Kappelman and Sevket Sen 13. The Late Miocene small mammal succession in Ukraine Valentin A. Nesin and Vadim A. Topachevsky Part III. Palaeoenvironments: Non-Mammalian Evidence: 14. Marine invertebrate (chiefly foraminiferal) evidence for the palaeogeography of the Oligocene-Miocene of western Eurasia, and consequences for terrestrial vertebrate migration Robert Wynn Jones 15. Palaeoclimatic implications of the energy hypothesis from Neogene corals of the Mediterranean region Brian R. Rosen 16. Contribution to the knowledge of Neogene climatic changes in western and central Europe by means of non-marine molluscs Daniela Esu 17. Sedimentary facies analysis in palaeoclimatic reconstructions. Examples from the Upper Miocene-Pliocene successions of south-central Tuscany (Italy) Marco Benvenuti, Mauro Papini and Giovanni Testa 18. Neogene vegetation changes in western European and west circum-Mediterranean areas Jean-Pierre Suc, Severine Fauquette, Mostefa Bessegik, Adele Bertini, Zhuo Zheng, Georges Clauzon, Danica Suballyova, Fiomena Diniz, Pierre Quezel, Najat Feddi, Martine Clet, Ezzedine Bessais, Naima Bachiri Taoufiq, Henriette Meon and Nathalie Combourieu-Nebout Part IV. Palaeoenvironments: Mammalian Evidence: 19. Shrews (Mammalia, Insectivora, Soricidae) as palaeoclimatic indicators in the European Neogene Jelle W.F. Reumer 20. Mammal turnover and global climate change in the Late Micoene terrestrial record of the Valles- Penedes basin (NE Spain) Jorge Agusti , Lluis Cabrera, Miguel Garces and Manel Llenas 21. Palaeoenvironments of Late Miocene primate localites in Macedonia, Greece L. de Bonis, G. Bouvrain and G. D. Koufos 22. The paleoecology of the Pikermian biome and the savanna myth Nikos Solounias, J. Michael Plavcan, Jay Quade and Lawrence Witmer 23. Vicariance biogeography and paleoecology of Eurasian Miocine hominoid primates Peter Andrews and Raymond L. Bernor 24. Conclusion J. Agusti, L. Rook and P. Andrews.

Cranial morphometry of early hominids: facial region.

We report here on early hominid facial diversity, as part of a more extensive morphometric survey of cranial variability in Pliocene and early Pleistocene Hominidae. Univariate and multivariate techniques are used to summarise variation in facial proportions in South and East African hominids, and later Quaternary groups are included as comparators in order to scale the variation displayed. The results indicate that "robust" australopithecines have longer, broader faces than the "gracile" form, but that all australopithecine species show comparable degrees of facial projection. "Robust" crania are characterised by anteriorly situated, deep malar processes that slope forwards and downwards. Smaller hominid specimens, formally or informally assigned to Homo (H. habilis, KNM-ER 1813, etc.), have individual facial dimensions that usually fall within the range of Australopithecus africanus, but which in combination reveal a significantly different morphological pattern; SK 847 shows similarly hominine facial proportions, which differ significantly from those of A. robustus specimens from Swartkrans. KNM-ER 1470 possesses a facial pattern that is basically hominine, but which in some respects mimics that of "robust" australopithecines. Early specimens referred to H. erectus possess facial proportions that contrast markedly with those of other Villafranchian hominids and which suggest differing masticatory forces, possibly reflecting a shift in dietary niche. Overall the results indicate two broad patterns of facial proportions in Hominidae: one is characteristic of Pliocene/basal Pleistocene forms with opposite polarities represented by A. boisei and H. habilis; the other pattern, which typifies hominids from the later Lower Pleistocene onwards, is first found in specimens widely regarded as early representatives of H. erectus, but which differ in which certain respects from the face of later members of that species.

Variations in enamel thickness and structure in East African hominids.

Tooth fragments are an appreciable but neglected proportion of fossil hominid specimens. The present study on 47 naturally fractured enamel surfaces of premolar and molar teeth of Plio-Pleistocene East African hominids measured enamel thickness, slope of incremental lines (striae of Retzius), and the morphology of Hunter Schreger bands (HSBs). Specimens allocated to three categories--"robust" australopithecines (EAFROB), "early Homo" (EAFHOM), and "unknown"--were photographed in ethanol with polarised light. Enamel thickness was measured on the occlusal (OT), cuspal (CT), and lateral (LT) aspects. The angle of intersection of striae of Retzius (D) with the enamel-dentine junction (EDJ) was recorded, together with the degree of curvature and width of Hunter-Schreger bands (HSB). Absolute measurements of enamel thickness were scaled by using two allometry correction factors. Absolute thicknesses of all enamel measurements were significantly greater in the EAFROB (OT 3.1 mm; CT 3.3 mm; LT 2.4 mm) compared with EAFHOM (OT 1.4 mm; CT 1.6 mm; LT 1.6 mm) categories. Correction for size reduces the mean difference between the two taxa, but CT and OT thickness remain significantly different (P less than 0.05). HSBs in EAFROB were relatively straight and narrower (means = 52.8 micron) than in EAFHOM, which are more curved and wider (means = 62.0 micron), suggesting greater enamel prism decussation in early Homo. The slope of striae was less in EAFROB permanent molars (means = 23 degrees) compared with EAFHOM (means = 31 degrees), indicating faster rates of coverage during crown formation in "robust" australopithecines. We conclude that the study of fractured enamel surfaces can contribute to our understanding of the systematic relationships and patterns of enamel growth of early hominids.

A statistical approach to temporal biostratigraphy

Various statistics (similarity coefficients) can be constructed for faunal assemblages which vary more or less regularly as these assemblages change. Methods are described for placing assemblages on an evolutionary scale, the units of which are equal amounts of evolutionary transformation in the species makeup of assemblages. The greatest single factor involved in the scaling appears to be time; the effects of zoogeography are also discussed. Characteristics of different similarity coefficients differ, and some of these characteristics are discussed. Applying our method to faunal assemblages from East African hominid sites, reasonable correlations can be established between Olduvai Gorge, Tanzania, the Shungura Formation, Ethiopia, and the Koobi Fora Formation, Kenya.

New endocranial values for the East African early hominids.

THIS is a preliminary report on research carried out during 1971 and 1972 on the endocranial values of some East African hominids from Olduvai Gorge, Tanzania, and East Lake Rudolf, Kenya. The cranial remains suitable for the reconstruction of volumetrically accurate endocranial casts are as follows: from Olduvai Gorge, hominids OH 7, 9, 12, 13 and 24; from East Lake Rudolf, KNM-ER 732 and 406. Each set of hominid remains required its own reconstructive procedures; a full description of each is unnecessary here but will be published elsewhere. In this communication I report only the results and make some preliminary observations as to their significance. Table 1 shows the cranial capacities found for each hominid. Not all of these results should be equally regarded; some results are only approximations but others are stated with more confidence.

The Olduvai Discoveries

Dr Napier and Dr Weiner quote from my preliminary reports and add, ‘All these opinions must be regarded as quite provisional for only detailed anatomical and statistical investigation will permit the assessment of the precise position of these new East African hominids within the evolutionary sequence’. Having said this, they then proceed to devote several pages to trying to assess the position of these new discoveries, when neither of them has made any detailed anatomical or statistical investigation of any of the skull and jaw material referred to, while the first author (at the time of writing) was only at an early stage of his study of the limb bones of the pre-Zinjanthropus juvenile.