Jabuticabeira II: Sambaqui Coast

The Jabuticabeira II site is part of the larger sambaqui phenomenon—large shell-mound (sambaqui) settlements built along Brazil's Atlantic coast. Archaeological deposits at Jabuticabeira II contain dense layers of shell, fish bone, and occasional hearths and burials that record repeated, long-term use of rich littoral resources. Radiocarbon dates associated with the human remains analyzed here fall within 364–57 BCE, placing these individuals in the late Sambaqui phase approximately 2,200 years before present.

Archaeological data indicates these coastal communities emerged from millennia of maritime foraging and local adaptation to estuaries and bays. Shell mounds accumulated as both midden and monumentalized places—locations of daily processing, ritual activity, and interment. Spatial patterns in Meso- and macro-faunal remains, the architecture of midden layers, and mortuary treatments at Jabuticabeira II point to a community structured around marine resources and repeated seasonal practices.

Limited evidence suggests that sambaqui populations maintained long-term occupation of favored coastal promontories, but the origins of specific lineages and the degree of interaction with inland groups remain uncertain. The DNA results presented here are from only two individuals, so any narratives of population movement or social organization must be treated as provisional and hypothesis-generating rather than definitive.

Ancient DNA from two individuals excavated at Jabuticabeira II yields a clear maternal signal: both samples carry mitochondrial haplogroup C1c. Haplogroup C1c is one of several founding Native American maternal lineages distributed across the Americas, and its presence at a late Sambaqui site is consistent with regional continuity of Indigenous maternal lineages along the Atlantic coast. However, no Y-chromosome haplogroup information is reported for these individuals, so paternal lineage patterns are currently unresolved.

Because the sample count is only two, genetic inferences must remain cautious. Two concordant mtDNA results can indicate a localized maternal continuity or kin clustering within a burial context, but they are insufficient to demonstrate population-wide patterns. Archaeogeneticists therefore treat these findings as preliminary: they are valuable as direct time-anchored data points that can be compared to larger datasets as more samples become available.

When integrated with archaeological evidence, the mtDNA results help anchor hypotheses about mobility, kinship, and community structure. For example, repeated maternal haplogroups in a single mound might reflect matrilocal residence or family-based burial practices, but alternative explanations—sample bias, small burial population, or post-depositional mixing—cannot be excluded. Future sampling, isotopic mobility analyses, and comparison to inland and later coastal populations will be essential to move from tentative observation to robust population history.