Neo-Assyrian Empire fall

What felled the great Assyrian Empire? A Yale professor weighs in

The Neo-Assyrian Empire, centered in northern Iraq and extending from Iran to Egypt -- the largest empire of its time -- collapsed after more than two centuries of dominance at the fall of its capital, Nineveh, in 612 B.C.E.

Despite a plethora of cuneiform textual documentation and archaeological excavations and field surveys, archaeologists and historians have been unable to explain the abruptness and finality of the historic empire's collapse.

Numerous theories about the collapse have been put forward since the city and its destruction levels were first excavated by archaeologists 180 years ago. But the mystery of how two small armies -- the Babylonians in the south and the Medes in the east -- were able to converge on Nineveh and completely destroy what was then the largest city in the world, without any reoccupation, has remained unsolved.

A team of researchers -- led by Ashish Sinha, California State University, Dominguez Hills, and using archival and archaeological data contributed by Harvey Weiss, professor of Near Eastern archaeology and environmental studies at Yale -- was able for the first time to determine the underlying cause for the collapse. By examining new precipitation records of the area, the team discovered an abrupt 60-year megadrought that so weakened the Assyrian state that Nineveh was overrun in three months and abandoned forever. The research was published in Science Advances on Nov. 13.

Assyria was an agrarian society dependent on seasonal precipitation for cereal agriculture. To its south, the Babylonians relied on irrigation agriculture, so their resources, government, and society were not affected by the drought, explains Weiss.

The team analyzed stalagmites -- a type of speleothem that grows up from a cave floor and is formed by the deposit of minerals from water -- retrieved from Kuna Ba cave in northeast Iraq. The speleothems can provide a history of climate through the oxygen and uranium isotope ratios of infiltrating water that are preserved in its layers. Oxygen in rainwater comes in two main varieties: heavy and light. The ratio of heavy to light types of oxygen isotopes are extremely sensitive to variations in precipitation and temperature. Over time, uranium trapped in speleothems turns into thorium, allowing scientists to date the speleothem deposits.

Weiss and the research team synchronized these findings with archaeological and cuneiform records and were able to document the first paleoclimate data for the megadrought that affected the Assyrian heartland at the time of the empire's collapse, when its less drought-affected neighbors invaded. The team's research also revealed that this megadrought followed a high-rainfall period that facilitated the Assyrian empire's earlier growth and expansion.

"Now we have a historical and environmental dynamic between north and south and between rain-fed agriculture and irrigation-fed agriculture through which we can understand the historical process of how the Babylonians were able to defeat the Assyrians," said Weiss, adding that the total collapse of Assyria is still described by historians as the "mother of all catastrophes."

Through the archaeology and history of the region, Weiss was able to piece together how the megadrought data were synchronous with Assyria's cessation of long-distance military campaigns and the construction of irrigation canals that were similar to its southern neighbors but restricted in their agricultural extent. Other texts noted that the Assyrians were worrying about their alliances with distant places, while also fearing internal intrigue, notes Weiss.

"This fits into a historical pattern that is not only structured through time and space, but a time and space that is filled with environmental change," says Weiss. "These societies experienced climatic changes that were of such magnitude they could not simply adapt to them," he adds.

With these new speleothem records, says Weiss, paleoclimatologists and archaeologists are now able to identify environmental changes in the global historical record that were unknown and inaccessible even 25 years ago. "History is no longer two-dimensional; the historical stage is now three-dimensional," said Weiss.

Neo-Assyrian Empire fall
Deportees after the Assyrian siege of Lachish, Judea (701 B.C.E.). Detail from bas-relief removed from Sennacherib's 'Palace Without Rival,' Nineveh, Iraq, and now in The British Museum. Photo credits: The British Museum

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Weiss' previous research defined the 2200 B.C.E. global megadrought that generated societal collapse from the Mediterranean to China.

In addition to Weiss, researchers from California State University-Dominguez Hills, Xi'an Jiaotong University, University of Minnesota, University of Colorado-Boulder, University of Illinois-Chicago, University of Ankara, and University of Southern California contributed to the study.

The press release for the study Role of climate in the rise and fall of the Neo-Assyrian Empire comes from the Yale University.

The study Role of climate in the rise and fall of the Neo-Assyrian Empire, by Ashish Sinha, Gayatri KathayatHarvey WeissHanying Li, Hai ChengJustin ReuterAdam W. Schneider, Max Berkelhammer, Selim F. Adalı, Lowell D. Stott and R. Lawrence Edwards, was published in Science Advances on Nov. 13rd.

 


Meet Callichimaera perplexa, the platypus of crabs

Meet Callichimaera perplexa, the platypus of crabs

Callichimaera perplexa Cretaceous
The diversity of body forms among crabs, including the enigmatic Callichimaera perplexa (center). Credit: Photos, Arthur Anker & Javier Luque; figure, Javier Luque, Yale University

New Haven, Conn. - The crab family just got a bunch of new cousins -- including a 95-million-year-old chimera species that will force scientists to rethink the definition of a crab.

An international team of researchers led by Yale paleontologist Javier Luque announced the discovery of hundreds of exceptionally well-preserved specimens from Colombia and the United States that date back to the mid-Cretaceous period of 90-95 million years ago. The cache includes hundreds of tiny comma shrimp fossils, several true shrimp, and an entirely new branch of the evolutionary tree for crabs.

The most intriguing discovery, according to the researchers, is Callichimaera perplexa, the earliest example of a swimming arthropod with paddle-like legs since the extinction of sea scorpions more than 250 million years ago. The name derives from a chimera, a mythological creature that has body features from more than one animal. Callichimaera's full name translates into "perplexing beautiful chimera."

Luque noted that Callichimaera's "unusual and cute" appearance, including its small size -- about the size of a quarter -- large compound eyes with no sockets, bent claws, leg-like mouth parts, exposed tail, and long body are features typical of pelagic crab larvae. This suggests that several of the larval traits seen in this "perplexing chimera" might have been retained and amplified in miniaturized adults via changes in the timing and rates of development. This is a process called "heterochrony," which may lead to the evolution of novel body plans.

"Callichimaera perplexa is so unique and strange that it can be considered the platypus of the crab world," said Luque. "It hints at how novel forms evolve and become so disparate through time. Usually we think of crabs as big animals with broad carapaces, strong claws, small eyes in long eyestalks, and a small tail tucked under the body. Well, Callichimaera defies all of these 'crabby' features and forces a re-think of our definition of what makes a crab a crab."

A study about the discovery appears in the April 24 online edition of the journal Science Advances.

"It is very exciting that today we keep finding completely new branches in the tree of life from a distant past, especially from regions like the tropics, which despite being hotspots of diversity today, are places we know the least about in terms of their past diversity," Luque said.

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Luque's team included researchers from the University of Alberta, Kent State University, the University of Montreal, the Smithsonian Tropical Research Institute in Panama, the Canadian Parks and Wilderness Society, the National Autonomous University of Mexico, the University of Nevada, and the College of Communication and Design in Boca Raton, Fla.

Artistic reconstruction of Callichimaera perplexa, the strangest crab that has ever lived. Credit: Elissa Martin, Yale Peabody Museum of Natural History

Press release from Yale University