Early Pleistocene large mammals from Maka’amitalu, Hadar, lower Awash Valley, Ethiopia

• The Early Pleistocene was a critical time period in the evolution of eastern Africanmammal faunas, but fossil assemblages sampling this interval are poorly known fromEthiopia’s Afar Depression. Field work by the Hadar Research Project in theBusidima Formation exposures (~2.7–0.8 Ma) of Hadar in the lower Awash Valley,resulted in the recovery of an early Homo maxilla (A.L. 666-1) with associated stonetools and fauna from the Maka’amitalu basin in the 1990s. These assemblages aredated to ~2.35 Ma by the Bouroukie Tuff 3 (BKT-3). Continued work by the HadarResearch Project over the last two decades has greatly expanded the faunal collection.Here, we provide a comprehensive account of the Maka’amitalu large mammals(Artiodactyla, Carnivora, Perissodactyla, Primates, and Proboscidea) and discusstheir paleoecological and biochronological significance. The size of the Maka’amitalu assemblage is small compared to those from the Hadar Formation (3.45–2.95 Ma)and Ledi-Geraru (2.8–2.6 Ma) but includes at least 20 taxa. Bovids, suids, andTheropithecus are common in terms of both species richness and abundance, whereascarnivorans, equids, and megaherbivores are rare. While the taxonomic compositionof the Maka’amitalu fauna indicates significant species turnover from the HadarFormation and Ledi-Geraru deposits, turnover seems to have occurred at a constantrate through time as taxonomic dissimilarity between adjacent fossil assemblages isstrongly predicted by their age difference. A similar pattern characterizes functionalecological turnover, with only subtle changes in dietary proportions, body sizeproportions, and bovid abundances across the composite lower Awash sequence.Biochronological comparisons with other sites in eastern Africa suggest that the taxarecovered from the Maka’amitalu are broadly consistent with the reported age of theBKT-3 tuff. Considering the age of BKT-3 and biochronology, a range of 2.4–1.9 Mais most likely for the faunal assemblage.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Evolutionary Studies

Paleontology

Taxonomy

Zoology

Ecosystems and species history

Ekosystem och arthistoria

Publikations- och innehållstyp

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