For societies with writing systems, hereditary leadership is documented as one of the hallmarks of early political complexity and governance. In contrast, it is unknown whether hereditary succession played a role in the early formation of prehistoric complex societies that lacked writing. Here we use an archaeogenomic approach to identify an elite matriline that persisted between 800 and 1130 CE in Chaco Canyon, the centre of an expansive prehistoric complex society in the Southwestern United States. We show that nine individuals buried in an elite crypt at Pueblo Bonito, the largest structure in the canyon, have identical mitochondrial genomes. Analyses of nuclear genome data from six samples with the highest DNA preservation demonstrate mother–daughter and grandmother–grandson relationships, evidence for a multigenerational matrilineal descent group. Together, these results demonstrate the persistence of an elite matriline in Chaco for ∼330 years.

This paper addresses two topics central to the study of nonhierarchical, regional social networks, sometimes termed “tribal” social networks: (1) alternative models of the evolution of regional integration; and (2) the archaeological determination of characteristics of such regional networks. Problems in previous ethnological and archaeological studies are identified, and an alternative model is proposed. This is based on a more general theory of organizational processes in nonhierarchical social systems. Data from the prehistoric North American Southwest and Midwest are shown to support the more general model, which treats such networks as organizational responses to increasing environmental uncertainty occasioned by either cultural or physical ecological factors, or both.

Chaco Canyon in northwestern New Mexico has been the focus of much recent archaeological research on Pueblo groups who lived during the 9th through 12th centuries in the American Southwest. Here, we examine variation in mortuary patterns in the canyon, focusing in particular on one mortuary crypt, to address questions of social differentiation and the chronology of important sociopolitical processes. Based on new radiocarbon dates as well as reanalysis of the stratigraphy and spatial distribution of materials in the mortuary crypt, we conclude that significant social differentiation began in Chaco ca. 150-200 y earlier than suggested by previous research. We argue that social inequality was sanctified and legitimized by linking people to founders, ancestors, and cosmological forces.Chaco Canyon | archaeology | culture change | mortuary practice | cosmology

High-precision accelerator mass spectrometer (AMS) 14C dates of scarlet macaw (Ara macao) skeletal remains provide the first direct evidence from Chaco Canyon in northwestern New Mexico that these Neotropical birds were procured from Mesoamerica by Pueblo people as early as ∼A.D. 900–975. Chaco was a prominent prehistoric Pueblo center with a dense concentration of multistoried great houses constructed from the 9th through early 12th centuries. At the best known great house of Pueblo Bonito, unusual burial crypts and significant quantities of exotic and symbolically important materials, including scarlet macaws, turquoise, marine shell, and cacao, suggest societal complexity unprecedented elsewhere in the Puebloan world. Scarlet macaws are known markers of social and political status among the Pueblos. New AMS 14C-dated scarlet macaw remains from Pueblo Bonito demonstrate that these birds were acquired persistently from Mesoamerica between A.D. 900 and 1150. Most of the macaws date before the hypothesized apogeal Chacoan period (A.D. 1040–1110) to which they are commonly attributed. The 10th century acquisition of these birds is consistent with the hypothesis that more formalized status hierarchies developed with significant connections to Mesoamerica before the post-A.D. 1040 architectural florescence in Chaco Canyon.

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