Archaeology breakthrough: Second ‘hidden pyramid’ discovered inside iconic Mayan structure

Archaeologists have confirmed that the massive Kukulkan pyramid in eastern Mexico – one of the most iconic pyramids in the world – was built like a Russian nesting doll, with the discovery of two smaller pyramids hidden within its walls.

The first of the hidden pyramids was discovered back in the 1930s, built within the walls of the colossal Kukulkan tomb. Now an even smaller pyramid has been found inside that one – and the discoveries might not stop there. 

“To make matters more complicated, the third Russian doll moving in may actually be one of a set of several small dolls rattling around inside the same shell.

We just do not know,” anthropologist Geoffrey Braswell from the University of California, San Diego, who was not involved in the study, told The Associated Press. Built sometime between the 9th and 12th centuries, the Kukulkan pyramid is the centrepiece of the vast Chichen Itza complex in the Mexican state of Yucatán. 

Also known as El Castillo (meaning “the castle”), this colossal pyramid features 364 steps – one for every day of the year in the Maya calendar system – and stands 24 metres (79 feet) tall. A 6-metre-high (20-foot) temple sits on top of the pyramid and was dedicated to the featured serpent god, Kukulkan.

Back in 1931, archaeologists began investigating the insides of the pyramid, with suspicions that it could be hiding the remains of a much older version – something that was widely disbelieved at the time.

Over the course of the next five years, they discovered a room nicknamed the hall of offerings, containing a giant Chacmool statue, its nails, teeth, and eyes inlaid with mother of pearl.

They also found a room called the chamber of sacrifices, containing two carefully arranged rows of human bones, and an elaborate red jaguar statue, encrusted with 74 jade inlays for spots, and jade-studded eyes.

The researchers soon realised that there was a larger, much older pyramid hidden below and inside the Kukulkan pyramid, and it stands roughly 33 metres tall (108 feet).

Now, archaeologists have completed their latest investigation of that internal pyramid using a non-invasive imaging technique called tri-dimensional electric resistivity tomography, and report the discovery of a 10-metre-tall (33-foot) pyramid hidden inside the larger two.

At this stage, it’s not clear if this the same structure archaeologists detected back in the 1940s but couldn’t confirm – or something else entirely.

Oddly enough, it appears to have been built above a water-filled sinkhole called a cenote, which researchers detected under the Kukulkan pyramid just last year. 

It’s not clear if the Maya knew of the cenote themselves, but the fact that the pyramids were built directly on top of it, and that Kukulkan was a god of water (among other things), suggests that maybe they did.

“The structure that we have found, the new structure, is not completely in the centre of the Kukulkan pyramid. It is in the direction where the cenote is,” Rene Chavez Segura, from the National Autonomous University of Mexico, told CNN.

“This could either confirm or hypothesise that the Mayans when they built this structure that they knew of the existence of this cenote.”

According to Segura and his team, the smallest pyramid was likely built between 550 and 800 AD. The middle structure has between 800 and 1000 AD, while the outer one was finished between 1050 and 1300 AD.

The researchers are yet to publish their findings, so these dates and the pyramid’s structure will still need to be verified by independent teams, but it’s hoped that further investigations will continue, so we can figure out if there are even more pyramids hidden inside.

“If this could be investigated in the future, this structure would be significant, because it would speak to the first few periods of habitation of the site and would provide information about how the settlement developed,” Denisse Argote from Mexico’s National Institute of Anthropology and History told CNN.

Researchers Discover Fossils Of A Unique ‘Eagle Shark’ That Glided Through Seas About 93 Million Years Ago!

The eagle shark was probably not as fearsome as its name suggests. The ancient shark, described on March 19 in the journal Science, was most likely a slow-moving filter feeder that looked like a cross between a standard shark and a manta ray.

But the eagle shark lived about 95 million years ago, 30 million years before modern rays appeared in the ocean. The find has palaeontologists wondering if other ancient sharks took unusual shapes since many are known only by the teeth they left behind.

The eagle shark, or Aquilolomna milarcae, fossil has the opposite appearance: an entire skeleton, but no teeth were preserved that would have helped palaeontologists categorize it.

The researchers took signs from other aspects of its anatomy—like its broad head and wide, wing-like fins—to draw conclusions about the shark’s behaviour.

“As this shark probably fed on plankton, it didn’t need to go fast,” says Romain Vullo, first author of the new study and a palaeontologist at the Université de Rennes, to New Scientist’s Adam Vaughan. “Like modern manta rays, relatively slow swimming was enough to eat plankton.”

A quarry worker found the unusual shark fossil in the Vallecillo limestone quarry in 2012. The region in northeastern Mexico is a well-known repository of marine fossils like ammonites, fish and marine reptiles, according to a statement.

Local palaeontologist Margarito González González learned of the discovery and set to work carefully chipping away at the stone to reveal the fossil that was preserved within, Riley Black reports for National Geographic.

“My first thoughts on seeing the fossil were that this unique morphology is totally new and unknown among sharks,” says Vullo to National Geographic.

While its head and side fins are unusual, the eagle shark’s tail and tail fins resemble those of modern sharks. So the researchers suggest that the shark probably used its tail to propel itself forward and its long side fins for stabilization. Manta rays have a different strategy, flapping their wide side fins to propel themselves forward.

“One of the most striking features of Aquilolamna is that it has very long, slender pectoral [side] fins,” writes Vullo in an email to Laura Geggel at Live Science, “This makes the shark wider than long,” because it is just over six feet wide but only about 5.4 feet long.

The fossil didn’t show signs of a dorsal fin—the notorious sign of an approaching shark that sticks up above the water—or of pelvic fins, which are on the underside of the shark. It’s not yet clear whether the eagle shark lacked these fins, or if they just didn’t fossilize, per Live Science.

The biggest mystery surrounding the eagle shark comes from the lack of teeth in the fossil. Palaeontologists rely on sharks’ teeth to identify them and figure out their evolutionary relationship to other ancient sharks.

The eagle shark might have had tiny, pointed teeth like the basking shark and the megamouth—two modern filter-feeding sharks—or taken a different strategy.

“It is truly unfortunate that no teeth were preserved in the specimen that could have allowed researchers to determine the exact taxonomic affinity of the new shark,” says DePaul University paleobiologist Kenshu Shimada to National Geographic.

For now, the research team used the shape of the fossil’s vertebrae and the skeleton of its tail fin to classify it like a shark in the order Lamniformes, which includes filter-feeding sharks, mako sharks and the great white.

Future fossilized finds and analysis of the eagle shark’s anatomy could help scientists understand the strange shapes of sharks in the distant past.

“There are a lot of unusual features described by these authors, and I have some reservations about some of their interpretations,” says Humboldt State University palaeontologist Allison Bronson, who wasn’t involved in the study, to National Geographic. “Ao I would be excited to see further investigations of this new, remarkable fossil.”

Controversial cave discoveries suggest humans reached the Americas much earlier than thought

Stone tools unearthed in a cave in Mexico indicate that humans could have lived in the area as early as about 33,000 years ago, researchers reported. That’s more than 10,000 years before humans are generally thought to have settled North America.

This controversial discovery enters a new piece of evidence into the fierce debate about when and how the Americas were first populated.

“A paper like this one is really stirring up the pot,” says co-author Eske Willerslev, an evolutionary biologist at the University of Cambridge. It “will no doubt get a lot of arguments going.”

For decades, archaeologists thought the Americas’ first residents were the Clovis people — big game hunters known for their well-crafted spearpoints who crossed a land bridge from Asia to Alaska about 13,000 years ago. Recent, well-accepted archaeological discoveries suggest that North America’s first settlers actually arrived a few thousand years before the rise of the Clovis culture, by about 16,000 years ago, says Vance Holliday, an archaeologist at the University of Arizona in Tucson not involved in the new work.

If the new finds really are human tools, Holliday says, this would be the oldest evidence for a human-inhabited site anywhere in the Americas.

At Chiquihuite Cave in central Mexico, archaeologists unearthed what appear to be over 1,900 stone tools.

Using radiocarbon dating to determine the ages of charcoal, bone and other detritus surrounding the artefacts, the researchers determined that more than 200 of the tools were embedded in a layer of the earth as old as 33,150 to 31,400 years. Other artefacts were found in a layer as fresh as about 13,000 years old.

The tools, excavated from 2016 to 2017, do not resemble Clovis technology or any other stone tools found in the Americas, the researchers say.

This haul “has a lot of small blades and small flakes that were used for cutting,” says archaeologist Ciprian Ardelean of the Autonomous University of Zacatecas in Mexico.

His team also dug up squarish stone fragments that he suspects were used to make composite tools of some sort, assembled from pieces of rock stuck into wooden or bone shafts.

“People are going to disagree about whether this qualifies as evidence” of human activity, says Loren Davis, an archaeologist at Oregon State University in Corvallis not involved in the work. “These are rocks that were broken, but … people don’t have a monopoly on the physics involved with breaking rocks,” Davis says that a closer examination of the artefacts in person or via 3-D models could convince him that they are indeed relics of human craftsmanship.

Ben Potter, an archaeologist in Fairbanks, Alaska, affiliated with the Arctic Studies Center at Liaocheng University in China, is similarly “intrigued but unconvinced” that Chiquihuite Cave was an ancient human abode. He notes the crude shape of many of the artefacts, as well as the absence of other evidence — such as butchered animal remains or human DNA — that would peg the site as a human residence.

Neither the tools’ shape nor the apparent lack of other human-made remains disqualifies Chiquihuite Cave as an ancient dwelling, Ardelean says. He argues that archaeologists’ expectations of what North American stone tools should look like are overly influenced by the perfection of Clovis points, which were neatly chipped from brittle stone such as jasper. The limestone used by the Chiquihuite Cave dwellers was more difficult to work with, he says, so it makes sense that these implements would be more rugged.

As for corroborating evidence of human activity, Ardelean expects human DNA to turn up only in specific areas of the cave, like where people ate or relieved themselves. He and his colleagues may not have excavated those spots yet, he says. The swath of ground investigated in this dig was also far from the mouth of the cave, where ancient people would more likely have cooked, eaten, thrown out garbage and performed other daily activities, he says.

Anthropologist Ruth Gruhn of the University of Alberta in Edmonton “wasn’t a bit surprised” at the authors’ claim of 30,000-year-old human handiwork in Mexico.

This cave joins a handful of sites in Brazil that have shown evidence of human occupation more than 20,000 years ago — although those reports remain controversial. To convince many archaeologists that humans really were in the Americas so early, “what you need is an accumulation of sites of that antiquity,” says Gruhn, whose commentary on the new study appears in Nature.

If there were humans in Mexico more than 30,000 years ago, that would affect what route they could have taken south from Alaska, says geologist Alia Lesnek of the University of New Hampshire in Durham. Archaeologists have thought that if humans arrived about 16,000 years ago, they may have plodded south along the Pacific Coast.

That’s because a narrow, inland ice-free corridor between two ice sheets covering Canada would not have had enough plants or animals to sustain human travellers. But more than 30,000 years ago, those ice sheets had not yet reached their full extent, Lesnek says, opening up the possibility of inland migration.