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Significance Understanding the evolution, dispersals, behaviors, and ecologies of early AfricanHomo sapiensrequires accurate geochronological placement of fossils and artifacts. We introduce open-air occurrences of such remains in sediments of the Middle Awash study area in Ethiopia. We describe the stratigraphic and depositional contexts of our discoveries and demonstrate the effectiveness of recently developed uranium-series dating of ostrich eggshell at validating and bridging across more traditional radioisotopic methods (¹⁴C and⁴⁰Ar/³⁹Ar).Homo sapiensfossils and associated Middle Stone Age artifacts are placed at >158 and ∼96 ka. Later Stone Age occurrences are dated to ∼21 to 24 ka and ∼31 to 32 ka, firmly dating the upper portion of one of the longest records of human evolution. 

This article summarizes research conducted in the Sahuaripa and Bacanora valleys of Sonora, Mexico. Located in the Serrana culture area of the Sierra Madre Occidental, data from this region speaks to several prevalent debates regarding the precolonial era of Northwest Mexico. Radiocarbon dates support demographic reconstructions for sizeable populations post-1000 AD; a time when other regions of the Northwest/Southwest (NW/SW) experienced significant demographic changes. Material cultural patterns reflect substantial local and regional connections with neighboring Río Sonora groups and Huatabampo. Recovered polychrome ceramics demonstrate long-distance connections with Casas Grandes, and obsidian data reflect connections to the Sonora and other neighboring valleys. These data indicate the Sahuaripa Valley participated in a corridor of exchange, which potentially included interaction between Casas Grandes and West Mexico. These observations are relevant to macro-scale patterns of interaction in the late-precolonial NW/SW. Este trabajo resume las investigaciones realizadas en los valles de Sahuaripa y Bacanora de Sonora, México. Estos valles están localizados en el área cultural Serrana de la Sierra Madre Occidental. La información sirve para entender las interacciones culturales en la época prehispánica del noroeste de México. Los fechamientos indican que existían poblaciones considerables posteriores al año 1000 d. C. periodo histórico donde ocurrieron cambios demográficos significativos. Los materiales reflejan conexiones locales y regionales con los grupos de Río Sonora y Huatabampo. Las cerámicas policromadas demuestran vínculos culturales con Casas Grandes, y los datos de obsidiana reflejan su interacción con el valle de Sonora así como con otras regiones. Los datos indican que el valle de Sahuaripa sirvió como un corredor de intercambio, que incluía Casas Grandes y al occidente de México. Estas observaciones son relevantes para entender los patrones de interacción de mayor escala en el NW/SW.