GUATEMALA CITY — Researchers using a high-tech aerial mapping technique have found tens of thousands of previously undetected Mayan houses, palaces, fortifications, and pyramids in the dense jungle of Guatemala’s Peten region, suggesting that millions more people lived there than previously thought.
The discoveries, which also included highways and huge agricultural fields and irrigation canals, were announced last week by an alliance of US, European, and Guatemalan archeologists working with Guatemala’s Mayan Heritage and Nature Foundation.
The study estimates that 10 million people might have lived within the Maya Lowlands, meaning that kind of massive food production might have been needed.
‘‘That is two to three times more [inhabitants] than people were saying there were,’’ said Marcello A. Canuto, a professor of anthropology at Tulane University.
Researchers used a mapping technique called LiDAR, which stands for Light Detection And Ranging. It bounces pulsed laser light off the ground, revealing contours hidden by dense foliage.
The images revealed that the Mayans altered the landscape in a much broader way than previously thought; in some areas, 95 percent of available land was cultivated.
‘‘Their agriculture is much more intensive and therefore sustainable than we thought, and they were cultivating every inch of the land,’’ said Francisco Estrada-Belli, a research assistant professor at Tulane University, noting the ancient Mayas partly drained swampy areas for the purpose.
And the extensive defensive fences, ditch-and-rampart systems, and irrigation canals suggest a highly organized workforce.
‘‘There’s state involvement here because we see large canals being dug that are redirecting natural water flows,’’ said Thomas Garrison, assistant professor of anthropology at Ithaca College in New York.
In a separate development, the Egyptian Antiquities Ministry said Saturday that archeologists have discovered a 4,400-year-old tomb near the country’s famed pyramids at the Giza plateau just outside Cairo.
The tomb was found in a wider area of Giza’s western necropolis, which is known to be home to tombs from the Old Kingdom. It probably belonged to a priestess known as Hetpet, who archeologists believe was close to ancient Egyptian royals of the Fifth Dynasty.
The tomb, unveiled to the media Saturday, is made of mud brick and includes wall paintings in good condition depicting Hetpet observing different hunting and fishing scenes.
It was the latest of several recent archeological discoveries in Egypt that authorities hope will help revive the country’s staggering tourism sector. The area of the latest discovery is close to a new museum under construction that will house some of Egypt’s most unique and precious artifacts, including many belonging to King Tutankhamun.
Researchers hope to find more treasures from ancient Egypt buried under the vast desert, partly because of modern technology.
The 810 square miles of mapping done in Guatemala vastly expands the area that was intensively occupied by the Maya, whose culture flourished between approximately 1,000 BC and 900 AD. Their descendants still live in the region.
The mapping detected about 60,000 individual structures, including four major Mayan ceremonial centers with plazas and pyramids.
More than 800 square miles of the Maya Biosphere Reserve in Guatemala’s Petén region have been mapped, according to National Geographic, which will air a television special about the project Tuesday.
Garrison said this year he went to the field with the LiDAR data to look for one of the roads revealed. ‘‘I found it, but if I had not had the LiDAR and known that that’s what it was, I would have walked right over it because of how dense the jungle is.’’
Garrison noted that unlike some other ancient cultures, whose fields, roads, and outbuildings have been destroyed by subsequent generations of farming, the jungle grew over abandoned Maya fields and structures, both hiding and preserving them.
‘‘In this the jungle, which has hindered us in our discovery efforts for so long, has actually worked as this great preservative tool of the impact the culture had across the landscape,’’ noted Garrison, who worked on the project and specializes in the city of El Zotz, near Tikal.
LiDAR revealed a previously undetected structure between the two sites that Garrison says ‘‘can’t be called anything other than a Maya fortress.’’
‘‘It’s this hill-top citadel that has these ditch and rampart systems . . . when I went there, one of these things is 9 meters tall,’’ he noted.
In a way, the structures were hiding in plain sight.
‘‘As soon as we saw this we all felt a little sheepish,’’ Canuto said of the LiDAR images, ‘‘because these were things that we had been walking over all the time.’’