Laguna Chica Foragers, c. 6800 BP

The Laguna Chica horizon sits in the coastal and lowland Pampas of central Argentina, a landscape reshaped by post‑glacial climates in the Early to Middle Holocene (roughly 7000–4500 BCE). Archaeological data indicates episodic camp occupations and resource use along lacustrine margins and grassland ecotones. Limited radiocarbon and stratigraphic evidence links the site to broader Pampas settlement trends that include mobile forager groups exploiting wetland and terrestrial resources.

Genetically, the tiny ancient dataset from Laguna Chica preserves elements typical of early South American populations: maternal lineages A2, B2b and C1b and a single paternal lineage in haplogroup Q. These haplogroups are broadly distributed across ancient and modern Indigenous populations of the Americas, consistent with deep shared ancestry across the continent. However, with only three genomes recovered, any reconstruction of population movements, local continuity, or demographic change must remain provisional. Limited evidence suggests continuity with other Holocene Pampean sites, but more samples are needed to resolve whether Laguna Chica represents a long‑term local population or repeated seasonal use by diverse groups.

Archaeological indications from the Pampas generally suggest flexible forager lifeways during the Early Holocene, and Laguna Chica likely fits within that pattern. Excavated contexts, where present, typically show hearth features, small artifact scatters and faunal remains that point to short‑term camps, seasonal resource scheduling, and intimate knowledge of wetland and grassland resources. Material culture in comparable regional sites includes simple lithic tools for butchery and plant processing; however, direct associations at Laguna Chica are limited and must be described cautiously.

Social groups were probably small and mobile, organized around family units with extensive knowledge of local ecological cycles. Artistic or ritual expression is not well documented at this site level; where present in the Pampas, such expressions are often subtle and preserved in ephemeral forms. Archaeological data indicates adaptability to changing environments—an important survival trait during Holocene climatic variability. Because excavated sample sizes from Laguna Chica remain low, interpretations of social complexity, territory, and seasonal rounds are necessarily tentative and should be revised as more fieldwork and dating are completed.

Three ancient genomes from Laguna Chica provide a rare, if limited, genetic window into Early Holocene Pampas populations. Observed mitochondrial haplogroups—A2, B2b and C1b—are among the principal founding maternal lineages recorded across the Americas, and their presence here supports broad maternal continuity with other ancient and modern Indigenous groups. The single observed Y‑chromosome lineage belongs to haplogroup Q, the dominant paternal lineage in many Indigenous American populations.

Genetic signals from Laguna Chica are consistent with ancestral ties across South America, but the tiny sample count (<10) severely constrains population‑level inference. With three samples, population structure, sex‑biased processes, and admixture events cannot be robustly tested. Nevertheless, the data do contribute to continental datasets showing that early Holocene Pampas inhabitants carried the same major founding lineages seen elsewhere, aligning archaeological patterns of mobility and regional interaction with genetic continuity. Future sampling—more individuals and direct AMS dates—will be required to test hypotheses about local continuity, gene flow along the Pampas corridor, or links to Andean and Patagonian groups.

Laguna Chica’s genetic signatures resonate with living Indigenous communities and with other ancient genomes across South America, reinforcing a deep shared ancestry stretching back to the early Holocene. Archaeological continuity in the Pampas suggests long‑term regional adaptations that later populations would inherit and transform.

Because the dataset is small, any direct lineage claims to present‑day groups must be made cautiously: limited ancient samples can document the presence of ancestral haplogroups but cannot on their own establish continuity of specific communities. Still, these finds underscore the Pampas’ role as a dynamic corridor of human occupation and interaction. As targeted excavation and additional aDNA sampling proceed, Laguna Chica may help illuminate how early Holocene lifeways contributed to the mosaic of South American genetic and cultural diversity observed today.