Scientists detect traces of an ancient Mayan city in southern Mexico using laser-sensor technology

NEW ORLEANS — Archaeologists using laser-sensing technology have detected what may be an ancient Mayan city cloaked by jungle in southern Mexico, authorities said Wednesday.

The lost city, dubbed Valeriana by researchers after the name of a nearby lagoon, may have been as densely settled as the better-known pre-Hispanic metropolis of Calakmul, in the south part of the Yucatan peninsula.

What the study, published this week in the journal Antiquity, suggest is that much of the seemingly empty, jungle-clad space between known Maya sites may once have been very heavily populated.

''Previous research has shown that a large part of the present-day state of Campeche is a landscape that was transformed by its ancient inhabitants,'' said Adriana Velázquez Morlet of Mexico's National Institute of Anthropology and History, a co-author of the report. ''Now, this study shows that a little-known region was a urbanized landscape.''

Mexico's National Institute said about 6,479 structures have been detected in LiDAR images covering an area of about 47 square miles (122 square kilometers). The technique maps landscapes using thousands of lasers pulses sent from a plane, which can detect variations in topography that ware not evident to the naked eye.

Those images revealed structures that include what appear to be temple platforms, ceremonial ball courts, housing platforms, agricultural terraces and even what appears to be a dam. The Institute said the structures may date to between 250 and 900 A.D., but the settlement could have been started 100 years earlier.

A consortium of researchers made the discovery by using software to re-examine a 2013 LIDAR survey originally carried out to measures deforestation. While re-examining the data, Luke Auld-Thomas, then a graduate student at Tulane University, noticed strange formations in the survey of the jungle.

Auld-Thomas's advisor, Tulane professor Marcello Canuto, said the extensive data they've collected will ''allow us to tell better stories of the ancient Mayan people,'' marrying what scientists already know – political and religious histories – with new details about how ancient civilizations were run.

''We have always been able to talk about the ancient Maya especially in the lowland regions because of their hieroglyphic texts, because they left us such interesting record," he said. ''What we are now able to do is match that information with their settlement and the population and what they were fighting over, what they were ruling over, what they were trading.''

Susan D. Gillespie, an anthropology professor at the University of Florida who was not connected to the study, said that while LiDAR is a valuable tool, some of the features would have to be confirmed by researchers on the ground.

''They realize that small natural rock piles (chich in the local parlance) were likely misinterpreted as house mounds, being the same size and shape. Thus, they recognize that their feature counts are preliminary,'' Gillespie wrote.

''The final caveat, which I think must always kept in mind, is contemporaneity of use of mapped features,'' Gillespie said. ''LiDAR maps what's on the surface, but not when it was used. So, a large region might be dense with structures, but the size of an occupation at any one time cannot known with aerial survey data alone.''