OCOSINGO, MEXICO (EFE).- Mexican archaeologists working at the Mayan acropolis of Tonina in the jungles of the southern state of Chiapas discovered a more-than-1,000-year-old sarcophagus they say could help clear up the mystery of the fall of the Maya civilization.

Juan Yadeun, who heads the archaeological dig located in the municipality of Ocosingo, said that the sarcophagus measures 2 meters (yards) long by 70 centimeters (27.5 inches) wide and 60 centimeters (about 2 feet) deep, and it is comparable in its importance to the "Red Queen" in Palenque, Chiapas, discovered in 1994.

The archaeologist said that the object dates from the years 840-900, the epoch when the last known Maya inscription was made.

"In A.D. 840 there was a very important transformation in the Maya cities. They stopped producing sculptural representations and inscriptions, which has been interpreted as a massive abandonment of the settlements," Yadeun said.

He said that the sarcophagus "will contribute new elements on the collapse of the ancient Maya civilization, (like) knowing with precision who were the causes of the decline, if it was local people influenced by groups from the Altiplano, coming directly from this part of Mesoamerica or from what today is (the southeastern state of) Tabasco."

Inside the sarcophagus was found a jar and a skull with traces of deformities and broken in several spots, as well as limb bones arranged in the form of a cross, apparently of "a personage of the top hierarchy, probably a woman or a child."

Within the crypt was also found a spherical jar with a lid containing bones that were boiled and fragmented, placed there some 500 years ago by Tzeltal Indians who settled in the area, restored some of the buildings for their own use and opened the local tombs to remove the objects within and place new items, including offerings, inside.

Yadeun said that among the different theoretical explanations is one that says the Maya civilization disappeared after the arrival of Toltec peoples from the central high plateau.

"This involved groups of a corporative character, large armies, that perhaps came from the Puebla-Tlaxcala area (in central Mexico), the Gulf Coast and Oaxaca (in the south), linked to Tula at the same time," he said.

Yadeun said that the ninth century brought a very important transformation in the Maya cities, a situation that suggests that "in those times in Ancient Mexico a revolution was brewing, with the fall of the dynasties and the coming to power of groups of warriors."

Between 688 and 708, Tonina, along with its ruler Chaak Bak Nal, was "the military was the largest military empire in Maya history until the arrival of the Aztecs."

This site, closed to the public since its discovery four years ago, also contains a mural that has been restored and contains the history of the pyramid that forms part of a complex measuring 320 meters along each side and 63 meters high, a structure considered to be one of the largest pyramids in the world. EFE