Limão Sambaqui: Coastal Memory

Sambaqui do Limão sits within the long-lived sambaqui tradition of Brazil's Atlantic littoral — monumental shell middens that accumulated over generations. Archaeological data indicates that by the Late Holocene coastal communities were constructing dense deposits of shell, bone, charcoal and hearths along sheltered bays and estuaries. The radiocarbon-constrained window for the human individual represented here (1442–1616 CE) places the burial within a dynamic era when long-standing coastal lifeways persisted alongside mounting Indigenous social complexity and the initial decades of European contact on the Brazilian coast.

The site’s stratigraphy preserves repeated episodes of shell deposition, hearthing, and organic refuse typical of sambaquis, which archaeologists interpret as both refuse landscapes and stages for ritual and burial practices. Limited evidence from nearby sambaquis suggests these mounds could serve as landmarked places of memory, seasonal aggregation, and local exchange. While sambaquis across the southeast coast vary in size and age, Sambaqui do Limão offers a late date that helps anchor the tail end of pre-contact coastal occupation in this locality.

Because the genetic evidence comes from a single sampled individual, interpretations about population origins, migration, or continuity must remain cautious. Archaeology provides the cultural and environmental context; the lone mitochondrial lineage offers one thread in a much larger human tapestry that still awaits fuller sampling.

Ancient DNA from Sambaqui do Limão is extremely limited: a single individual yields mitochondrial haplogroup B2. Haplogroup B2 is a well-known Native American maternal lineage that traces back to founding populations of the Americas and persists in many present-day Indigenous groups across South and Central America. The presence of B2 at this southeast Brazilian sambaqui aligns the Limão individual with broader pan-American maternal ancestries rather than indicating a unique, isolated lineage.

However, several important caveats shape interpretation. First, the sample count is one — far below thresholds needed to describe population structure, sex-biased migration, or admixture. Second, Y-chromosome lineages were not reported for this individual, so male-line history at the site remains unknown. Third, the date window (1442–1616 CE) overlaps early post-contact centuries; without genome-wide data it is not possible to robustly detect subtle European, African, or inter-Indigenous admixture at the individual level.

Archaeology supplies cultural context while aDNA provides biological signals: together they suggest continuity of Native American maternal lines into the late-pre-contact and contact-era coastal landscape. But given the single sample, conclusions are preliminary. Future sampling from multiple burials, combined genome-wide analyses, and careful contamination controls are essential to test continuity, mobility, and interaction hypotheses.