Cueva de los Muertos Chiquitos (Rio Zape)

The human remains from Cueva DeLos Muertos Chiquitos (Rio Zape) occupy a dramatic stretch of Late Holocene time, with archaeological contexts dated between roughly 100 and 1400 CE. Stratigraphic evidence and radiocarbon chronology indicate episodic use of the cave as a mortuary place over many centuries rather than a single occupation event. The site sits within the broader ecological transition zones of northern Mexico where mobility, resource patchiness, and cultural exchange shaped small communities.

Archaeological data indicates that the cave functioned primarily for internment and perhaps ritualized deposition. Associated artifacts and burial arrangements recovered in excavations suggest local traditions of funerary care that persisted across generations. Limited evidence suggests interaction with neighboring cultural spheres during the later part of the sequence; however, material parallels remain patchy and interpretation is cautious.

Genetic sampling of individuals from the cave now adds a biological dimension to origin questions. Ancient DNA provides lineage-level detail that complements the archaeological record, revealing which deep maternal and paternal branches were present in this locality across the Late Holocene. Because the current genetic dataset is small (9 individuals), conclusions about origins and population movements remain provisional and invite further sampling.

Nine ancient individuals from Cueva DeLos Muertos Chiquitos were successfully genotyped, a modest set that nonetheless reveals clear tendencies. Paternal markers: four males carry Y-chromosome haplogroup Q, a lineage widely associated with Indigenous peoples of the Americas. Maternal markers: mtDNA is dominated by haplogroup B (5 individuals), with smaller counts of A2c (2) and C (2). These maternal lineages are among the founding Native American mtDNA branches recognized across Mesoamerica and beyond.

The prominence of mtDNA B in this small sample suggests a notable maternal signal at Rio Zape, while the presence of A2c and C indicates maternal diversity consistent with regional Late Holocene variation. The occurrence of Y-haplogroup Q aligns with pan-American paternal continuity but cannot by itself resolve local demographic processes. Because the dataset contains fewer than ten genomes, statistical power is limited: patterns such as sex-biased migration, kinship structure, or regional continuity vs. replacement remain hypotheses rather than firm conclusions.

Genetic affinities inferred from allele-sharing and haplogroup composition tentatively place these individuals within the broader genetic landscape of northern Mexico and adjacent regions. Continued sampling, comparative datasets from contemporaneous sites (e.g., Casas Grandes/Paquimé area), and integration with stable isotope and radiocarbon data will be necessary to move from suggestive patterns to robust models of population change.