Archaeologists working in Guatemala at the Xultun ruins of the Mayan civilization have reported striking finds, including the oldest-known Mayan astronomical tables.
The site, in Guatemala, includes the first known instance of Mayan art painted on the walls of a dwelling.
A report in Science says it dates from the early 9th Century, pre-dating other Mayan calendars by centuries.
Such calendars rose to prominence recently amid claims they predicted the end of the world in 2012.
The Mayan civilization occupied Central America from about 2000 BC until its decline and assimilation following the colonization by the Spanish from the 15th Century onwards. It still holds fascination, with many early Mayan sites still hidden or uncatalogued.
The ruins at Xultun were first discovered in 1912 and mapping efforts in the 1920s and 1970s laid out much of the site’s structure.
Archaeologists have catalogued the site’s features, including a 35m-tall pyramid, but thousands of structures on the 30 sq km site remain unexplored.
In 2005, William Saturno, then at the University of New Hampshire, discovered the oldest-known Mayan murals at a site just a few kilometres away called San Bartolo.
in 2010, one of Dr Saturno’s students was following the tracks of more recent looters at Xultun when he discovered the vegetation-covered structure that has now been excavated.
When Mayans renovated an old structure, they typically collapsed its roof and built on top of the rubble. But for some reason, the new Xultun find had been filled in through its doorway, with the roof left intact.
Dr Saturno, who is now based at Boston University, explained that despite it being under just a metre of soil today, that served to preserve the site after more than a millennium of rainy seasons, insect traffic and encroaching plant and tree roots.
“We found that three of the room’s four walls were well preserved and that the ceilings were also in good shape in terms of the paintings on them, so we got an awful lot more than we bargained for,” he said.