Unveiling the Dinosaur’s Menu: A Fossilized Time Capsule Reveals the Sauropod’s Diet 100 Million Years Ago

A groundbreaking study published in the Cell Press journal Current Biology has shed light on the diet of one of the most fascinating creatures to have ever walked the Earth – the sauropod dinosaur. The research, led by Stephen Poropat of Curtin University, reveals that these gentle giants were herbivores and had a unique digestive system that relied heavily on gut microbes for digestion.

The study’s findings are based on an extraordinary discovery made in 2017 at the Australian Age of Dinosaurs Museum of Natural History. During an excavation of a sauropod skeleton from the mid-Cretaceous period, researchers stumbled upon a well-preserved cololite – a fossilized rock layer containing the dinosaur’s gut contents.

The analysis of the plant fossils within the cololite has confirmed several long-standing hypotheses about the sauropod diet. The research team found that these dinosaurs likely engaged in minimal oral processing of their food and instead relied on fermentation and their gut microbiota for digestion.

The variety of plants present in the cololite suggests that sauropods were indiscriminate bulk feeders, eating a range of foliage from conifers to leaves from flowering plants. This is supported by the presence of chemical biomarkers from both angiosperms and gymnosperms, indicating that at least some sauropods were not selective feeders.

The researchers’ findings have significant implications for our understanding of these massive herbivores and their role in ancient ecosystems. The study suggests that sauropods had successfully adapted to eat flowering plants within 40 million years of the first evidence of their presence in the fossil record.

In addition, the research team found evidence of small shoots, bracts, and seed pods in the cololite, implying that subadult Diamantinasaurus targeted new growth portions of conifers and seed ferns. This strategy of indiscriminate bulk feeding seems to have served sauropods well for 130 million years and might have enabled their success and longevity as a clade.

While this research has shed new light on the diet of sauropod dinosaurs, there are still limitations to consider. The study’s primary limitation is that the sauropod gut contents described constitute a single data point, which may not be representative of typical or adult sauropods’ diets.

This research was supported by funding from the Australian Research Council and has significant implications for our understanding of these fascinating creatures and their role in ancient ecosystems.

The fate of the West Antarctic Ice Sheet (WAIS) hangs precariously in the balance, with scientists warning that the next few years will be crucial in determining its future. A recent study published in Communications Earth & Environment has shed light on the alarming consequences of WAIS collapse, which could trigger a devastating four meters of global sea level rise over hundreds of years.

The researchers from the Potsdam Institute for Climate Impact Research (PIK), NORCE, and Northumbria University in the UK conducted extensive model simulations spanning 800,000 years to understand how the vast Antarctic Ice Sheet has responded to Earth’s climate fluctuations. Their findings revealed two stable states: one with WAIS intact, which is our current state, and another where the ice sheet has collapsed.

The primary driver of this collapse is rising ocean temperatures around Antarctica, which are mostly supplied by the ocean rather than the atmosphere. Once WAIS tips into the collapsed state, it would take several thousands of years for temperatures to drop back to pre-industrial conditions, reversing the damage.

“We have two stable states: one with WAIS intact and another where it has collapsed,” said lead author David Chandler from NORCE. “Once tipping has been triggered, it’s self-sustaining and seems very unlikely to be stopped before contributing to about four meters of sea-level rise. And this would be practically irreversible.”

The consequences of WAIS collapse would be catastrophic, with four meters of sea level rise projected to displace millions of people worldwide and wreak havoc on coastal communities.

However, there is still hope for a better outcome. Immediate actions to reduce emissions could avoid a catastrophic outcome, giving us a narrow window to act before it’s too late.

“It takes tens of thousands of years for an ice sheet to grow, but just decades to destabilise it by burning fossil fuels,” said co-author Julius Garbe from PIK. “Now we only have a narrow window to act.”

The discovery of a nearly complete fossil of what looked like a lizard or salamander in Scotland in 1984 has turned out to be a significant find. The creature, called Westlothiana lizziae, is one of the earliest examples of a four-legged animal that had evolved from living underwater to dwelling on earth. It and other stem tetrapods like it are common ancestors of the amphibians, birds, reptiles, and mammals that exist today, including humans.

Despite its significance, researchers had never determined an accurate age of the fossil. However, thanks to new research out of The University of Texas at Austin, scientists now know that the Westlothiana lizziae, along with similar salamander-like creatures from the same spot in Scotland, are potentially 14 million years older than previously thought.

The new age – dating back to 346 million years ago – adds to the significance of the find because it places the specimens in a mysterious hole in the fossil record called Romer’s Gap. This time period, from 360 to 345 million years ago, is where water-dwelling fish took an evolutionary leap, growing lungs and four legs to become land animals.

The research, published recently in the journal PLOS One, was led by Hector Garza, who just graduated with his doctoral degree from the Department of Earth and Planetary Sciences at the UT Jackson School of Geosciences. Garza used a geochemical technique called radiometric dating to determine the age of the fossils. This technique involves using zircon crystals to date rocks, but not all rock types are amenable to this type of analysis.

The site in Scotland where the fossils were discovered was near ancient volcanoes whose lava flows had long hardened into basalt rock, where zircons do not typically form. Fellow scientists warned Garza that chemically dating the rocks might be fruitless. However, he got lucky and was able to extract zircons from the rock surrounding six of the fossils.

Garza X-rayed 11 of the rock samples at the Jackson School and conducted uranium-lead laser dating on the zircons at the University of Houston to determine their oldest possible age. Before Garza’s gamble, scientists had figured the fossils were as old as similar fossils from around the world – about 331 million years old.

The more accurate, older maximum age of 346 million years is significant because it places the specimens in Romer’s Gap. This time period is crucial to understanding the timing of the emergence of vertebrates on land and why this transition occurs when it does.

“I can’t overstate the importance of the iconic East Kirkland tetrapods,” said Julia Clarke, professor at the Jackson School and co-author of this paper. “Better constraining the age of these fossils is key to understanding the timing of the emergence of vertebrates on to land. Timing in turn is key to assessing why this transition occurs when it does and what factors in the environment may be linked to this event.”

The site in Scotland where the fossils were found, the East Kirkton Quarry, is a veritable treasure trove of early tetrapod records. Seven stem tetrapod fossils, including the Westlothiana lizziae, have been found there. Hundreds of millions of years ago when these early four-legged creatures roamed, this site was a tropical forest with nearby active volcanoes, a toxic lake, and a diverse plant and animal community.

The National Museum of Scotland provided Garza with bits of rock that surrounded the fossils to use for the sampling. Other study co-authors are Associate Professor Elizabeth Catlos and Michael Brookfield, both of the Department of Earth and Planetary Sciences at the Jackson School, and Thomas Lapen, professor and chair of the Department of Earth and Atmospheric Sciences at the University of Houston.