Fossilized feces tells the story of the rise of dinosaurs

The contents of feces and vomit from 200 million years ago are helping to show how dinosaurs conquered the world at the beginning of the Jurassic period.

Whole insects embedded in various shapes and sizes of well-preserved plants, bones, fish parts, and even ancient animal feces show that dinosaurs varied in comparison to other groups of animals. This suggests that dinosaurs were able to survive in the ecosystem thanks to their wide-ranging diet. This led to their further growth and eventually led to the establishment of a “land dynasty.” Martin Kvarnström At Uppsala University, Sweden.

Fossil evidence shows that the first dinosaurs had prominent hip joints that placed their legs underneath their bodies like mammals, rather than sprawling sideways like lizards. More than 230 million years ago During the Triassic. For tens of millions of years, these early dinosaurs blended into a landscape filled with many other types of reptiles. But by about 200 million years ago, dinosaurs had essentially taken over the Earth, around the time most other reptiles disappeared during the end-Triassic extinction.

What led to this dominance remains somewhat of a mystery. Kvarnström and his colleagues suspected that important clues might be hidden in the bromalites (fossilized feces and vomit) of dinosaurs and other animals. So they Polish Geological Institutecollected by a prior research group from eight locations in Poland between 1996 and 2017.

The research team estimated the age of each bromalite based on the layer of sediment in which it was found, and determined its size, which ranges from a few millimeters to a “fairly large fecal mass,” and the animals that may have produced it. A suitable shape was used. The researchers then 3D scanned the fossil to examine its contents. “We noticed that it was clogged with food debris,” Kvarnström says.

Combining the known fossil record with past climate information, researchers determined that the emergence of dinosaurs occurred in several different stages. First, the omnivorous ancestors of early dinosaurs began to outnumber non-dinosaurs. They then evolved into the first carnivorous and plant-eating dinosaurs.

At that point, increased volcanic eruptions and movement of tectonic plates caused flooding and waterway development. The resulting humidity and related changes in climate likely led to a wider range of plants and the evolution of larger and more diverse herbivorous dinosaurs. On the other hand, non-dinosaur animals – dicynodonts that eat plants weighing up to 1 ton. Risouwisia, Their feces contained mainly coniferous debris and they were less able to adapt to changes in vegetation.

As herbivorous dinosaurs grew larger, so did their predators. By the beginning of the Jurassic period, about 30 million years after the first dinosaurs appeared, the transition to a dinosaur-dominated world was complete, Kvarnström says.

“This study shows how climate primarily affects dominant plants, which creates opportunities for new herbivores at certain points in time,” he says. michael benton from the University of Bristol, UK, was not involved in the study.

Although it’s difficult to be sure that the researchers matched the scat to the right animal, the discovery nonetheless suggests that the dinosaur species had already expanded significantly in South America before major climate change. This confirms earlier research, he says. “But it took the end-Triassic mass extinction for the final stage of the takeover to begin.”

for emma dunn The study, conducted at Germany’s Friedrich-Alexander University, helps answer long-standing questions about the emergence of dinosaurs. “It’s not every day that a fossil poop is published in such an influential journal,” said Dunn, who was not involved in the study. “This is obviously interesting, but it’s also very useful for understanding prehistoric environments. So if you think of the evolution of early dinosaurs like a jigsaw puzzle with pieces missing, there are new It’s just a lot of pieces thrown in.”