MEXICO CITY.- The discovery of ancient megafauna fossils in the community of San Sebastián Villanueva, in the municipality of Acatzingo, Puebla, has opened a remarkable new window onto Mexico’s prehistoric past. Mexico’s National Institute of Anthropology and History (INAH) has confirmed that the remains belong to several large animals that lived during the Late Pleistocene, including a glyptodont, a dire wolf, a prehistoric horse, and a ground sloth. The fossils are now being safeguarded by the Paleontology Section of the INAH Puebla Center, where they will undergo detailed study beginning in 2026.

The remains were uncovered along a dirt road known as Paso La Mora, after local residents alerted authorities to the find. Archaeologists and paleontologists carried out a careful recovery operation between October 21 and 24, 2025, working closely with the local community, the auxiliary presidency of San Sebastián Villanueva, and the cultural authorities of the Acatzingo municipality.

According to Iván Alarcón Durán, head of the Paleontology Section at the INAH Puebla Center and leader of the rescue effort, the fossils will now undergo a meticulous process of cleaning and stabilization. “When fossil remains are still embedded in sediment, they can remain stable for thousands of years,” Alarcón explained. “Once they are exposed, deterioration begins very quickly, so stabilization is essential to ensure their long-term preservation.”

Among the most striking discoveries are fragments of a glyptodont, an extinct relative of modern armadillos. Researchers recovered two pieces of the animal’s armored shell, along with several loose osteoderms. Glyptodonts were massive creatures, some as large as a compact car, weighing up to a ton and measuring around two and a half meters from head to tail. One of the shell fragments displays the distinctive rosette pattern typical of this group, confirming the identification.

The find is particularly significant because it closely relates to a glyptodont discovered in 2017 in nearby Santiago Tenango, just 15 kilometers away. That earlier specimen, identified as Glyptrotherium cylindricum, is the most complete ever found in Puebla and now forms the centerpiece of a local site museum.

Equally notable is the identification of a dire wolf (Aenocyon dirus), based on a fragment of the right upper jaw containing two molars. Dire wolves were formidable carnivores native to the Americas, but their remains are relatively rare. “Carnivores existed in smaller numbers, which makes their fossils harder to find,” Alarcón noted, underscoring the importance of the discovery.

The team also recovered a single molar from a prehistoric horse, likely belonging to Equus mexicanus, as well as a bone fragment believed to come from the leg of a ground sloth. While some ground sloths grew as large as mammoths, the individual represented here would have been closer in size to a modern polar bear.

Beyond their scientific value, the fossils have sparked strong interest among local residents, who hope to see the material eventually returned to the community. Inspired by the example of Santiago Tenango, San Sebastián Villanueva has already begun exploring the possibility of creating its own site museum. As Alarcón emphasized, the stabilization process will take months, but it will allow these fragile remains to be preserved for decades—ensuring that this chapter of Puebla’s deep history can be shared with future generations.