Pliocene hominins from East Turkana were associated with mesic environments in a semiarid basin
Villaseñor, Amelia; Uno, Kevin T.; Kinyanjui, Rahab N.; Behrensmeyer, Anna K.; Bobe, René; Advokaat, Eldert L.; Bamford, Marion; Carvalho, Susana C.; Hammond, Ashley S.; Palcu, Dan V.; Sier, Mark J.; Ward, Carol V.; Braun, David R.
(2023) Journal of Human Evolution, volume 180, pp. 1 - 19
(Article)
Abstract
During the middle Pliocene (∼3.8–3.2 Ma), both Australopithecus afarensis and Kenyanthropus platyops are known from the Turkana Basin, but between 3.60 and 3.44 Ma, most hominin fossils are found on the west side of Lake Turkana. Here, we describe a new hominin locality (ET03-166/168, Area 129) from the east side
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of the lake, in the Lokochot Member of the Koobi Fora Formation (3.60–3.44 Ma). To reconstruct the paleoecology of the locality and its surroundings, we combine information from sedimentology, the relative abundance of associated mammalian fauna, phytoliths, and stable isotopes from plant wax biomarkers, pedogenic carbonates, and fossil tooth enamel. The combined evidence provides a detailed view of the local paleoenvironment occupied by these Pliocene hominins, where a biodiverse community of primates, including hominins, and other mammals inhabited humid, grassy woodlands in a fluvial floodplain setting. Between <3.596 and 3.44 Ma, increases in woody vegetation were, at times, associated with increases in arid-adapted grasses. This suggests that Pliocene vegetation included woody species that were resilient to periods of prolonged aridity, resembling vegetation structure in the Turkana Basin today, where arid-adapted woody plants are a significant component of the ecosystem. Pedogenic carbonates indicate more woody vegetation than other vegetation proxies, possibly due to differences in temporospatial scale and ecological biases in preservation that should be accounted for in future studies. These new hominin fossils and associated multiproxy paleoenvironmental indicators from a single locale through time suggest that early hominin species occupied a wide range of habitats, possibly including wetlands within semiarid landscapes. Local-scale paleoecological evidence from East Turkana supports regional evidence that middle Pliocene eastern Africa may have experienced large-scale, climate-driven periods of aridity. This information extends our understanding of hominin environments beyond the limits of simple wooded, grassy, or mosaic environmental descriptions.
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Keywords: Australopithecus afarensis, Kenyanthropus platyops, Koobi Fora, Middle Pliocene hominin paleoecology, Multiproxy, Stable isotope ecology, Taverne, Ecology, Evolution, Behavior and Systematics, Anthropology
ISSN: 0047-2484
Publisher: Academic Press Inc.
Note: Funding Information: We thank the many skilled Kenyan field workers and fossil collectors. This research would not be possible without them. We are grateful to the National Museums of Kenya, NACOSTI, the Koobi Fora Field School, and the many field school students who participated in data collection and processing. We acknowledge Naomi Levin and Christopher Campisano, whose careful geologic and paleoecological records were foundational to this paper. We are grateful to the three anonymous reviewers, the Associate Editor, and the JHE Editor, Andrea Taylor, whose questions and insights improved the manuscript. We also thank Lucas Delezene for carefully editing the manuscript many times. This research was funded by the Leakey Foundation , the National Science Foundation ( SBE-1534824 and SBE-1624398 ), and the Ford Foundation . D.V.P. also acknowledges the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support through grant 2018/20733-6 . Funding Information: We thank the many skilled Kenyan field workers and fossil collectors. This research would not be possible without them. We are grateful to the National Museums of Kenya, NACOSTI, the Koobi Fora Field School, and the many field school students who participated in data collection and processing. We acknowledge Naomi Levin and Christopher Campisano, whose careful geologic and paleoecological records were foundational to this paper. We are grateful to the three anonymous reviewers, the Associate Editor, and the JHE Editor, Andrea Taylor, whose questions and insights improved the manuscript. We also thank Lucas Delezene for carefully editing the manuscript many times. This research was funded by the Leakey Foundation, the National Science Foundation (SBE-1534824 and SBE-1624398), and the Ford Foundation. D.V.P. also acknowledges the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support through grant 2018/20733-6. Publisher Copyright: © 2023 Elsevier Ltd
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