Archaeologists from Mexico’s National Institute of Anthropology and History (INAH) said Tuesday they have documented an ancient ceremonial complex carved into a hill in Guerrero state that includes mysterious indigenous carvings and large-scale architecture researchers believe are tied to sun and water rituals.
The site, known locally as Piedra Letra and located on a hill near the community of Huehuetónoc in the municipality of Tlacoachistlahuaca on the Costa Chica, was recorded by INAH specialists Cuauhtémoc Reyes Álvarez and Miguel Pérez Negrete during a surface inspection prompted by a municipal inventory exercise, the agency said in a statement.
INAH researchers inspected 11 pre-Hispanic locations across six communities, including Huehuetónoc, Limón Guadalupe, Jicayán de Tovar, Santiago Yoloxóchitl, San Cristóbal, and Guadalupe Mano de León. They identified a ceremonial center on the summit of a hill that includes a broad platform, two main bases, and other structural remains associated with a rocky outcrop carved with petroglyphs.
The mysterious indigenous carvings found in the monuments date back to the Early Postclassic age in Mexico
The rock art spans periods the archaeologists date to the Epiclásico–Early Postclassic (about AD 650–1150) and the Late Postclassic (about AD 1150–1521), covering roughly eight centuries of activity, INAH said.
“The motifs suggest Piedra Letra functioned as a place of ritual related to water and the sun,” the agency said. The petroglyphs include spirals, circular counting beads thought to mark time, water-drop motifs, a model of a ballcourt, a human figure wearing a circular pectoral and feathered headdress, and the profile of a jaguar whose body is marked with dot-like spots. A carved sun with a face was identified as a later motif, stylistically tied to the Late Postclassic period.
At nearby San Cristóbal, INAH recorded mounds and polished granite stelae rising as high as 2 meters (approximately 6 ft. 7 in.), and stones engraved with spirals and concentric circles. At Guadalupe Mano de León, investigators documented a platform with the remains of walls and a carved stone axe, evidence the agency called “monumental architecture” previously unrecorded in the municipality.
The Costa Chica region is remarkably under-researched by archaeologists
Reyes Álvarez said the Costa Chica region has been studied by researchers since the 1960s, but lacks a comprehensive archaeological record. “This reconnaissance is the first step toward research, protection, and conservation,” he said in the statement. This specific research grew out of a “Culture and Identity” session tied to a municipal Plan of Justice and Development for the Amuzgo people, in which Mayor Emmanuel Cuevas Rodríguez alerted INAH to the vestiges. The agency said Tlacoachistlahuaca’s landscape has long been a cultural crossroads where Amuzgo and Mixtec groups, and the now-extinct Ayacatecan people, interacted.
Pérez Negrete said documenting Piedra Letra and the newly recorded sites will help address questions about the origin and identity of the Amuzgo people, often told through varying oral histories, by supplying “hard data from archaeology.” INAH officials said the petroglyphs and other decorative elements will be compiled into an iconographic catalog to enrich the town’s cultural identity and support conservation planning. The agency did not immediately name plans for excavation or public display, but emphasized the need for protection of the rock carvings and the structures that remain on the ridge.
The findings add to a growing recognition of the Costa Chica’s archaeological importance and point to ritual practices, rain petitions, agricultural rites, and solar calendar observances that shaped life in the region long before the arrival of Europeans.
