Archaeologists uncover ancient skeletons they believe could be up to 1500 years old

The bones were uncovered during dig in the Mexican town of Pozo de Ibarra

Archaeologists in Mexico have discovered a cache of ancient bones they believe were part of a "complex funerary system" while preparing a sight for a construction project.

Experts found the skeletons in the town of Pozo de Ibarra while preparing a site for a sewage-related construction project, according to the National Institute of Anthropology and History.

At least seven intact skulls were discovered at the site. The skulls reportedly bore signs of "cranial modification," which the INAH said may have been done for aesthetic reasons.

The bones were arranged in a way that suggested an intentional structure to the grave site, according to the INAH.

"It is a funerary system composed of a primary burial, that is, the skeleton maintains the anatomical relationship, accompanied by a concentration of human bone remains deposited without anatomical relationship, which have a particular arrangement," the INAH said in a statement.

Certain bones, including femurs, tibias, rays, and ulnae — all of which are typically longer bones — were placed in a specific spot. Skulls were also intentionally placed together, with some stacked on top of others. They were placed in a different portion of the grave site.

A pile of skulls found during an archaeological dig in the Mexican town of Pozo de Ibarra (INAH)

Experts have not confirmed the age of the bones yet, but believe they could be up to 1,500 years old.

"The discovery is possibly related to the Amapa cultural phase (500-800/850 AD) because ceramic vessels and anthropomorphic figurines from that period were also recovered," the INAH said in the release.

The group praised the discovery both for its broader archaeological implications and for the quality of the site.

"This archaeological find is exceptional, since there are no precedents for this type of burial in other nearby sites, and it enriches the understanding of funerary practices in the region," the INAH said. "In addition, it encourages collaboration between the different INAH bodies for the protection, research, conservation and dissemination of heritage."