Fossilized feces and vomit might not be the most glamorous topic, but scientists have unearthed some fascinating insights about how dinosaurs came to rule the Earth through these unconventional sources. A new study, involving researchers from Poland, Sweden, Norway, and Hungary, has analyzed over 500 samples of fossilized excrement, known as bromalites, shedding light on the food webs and ecological dynamics of the Mesozoic era.
Dinosaurs roamed the Earth for around 165 million years, so you'd think we'd have plenty of details on their rise to dominance. Yet, surprisingly, scientists knew relatively little about how they ascended. According to Martin Qvarnstrom, the lead author of the new study from Uppsala University, “we know very little about their rise,” explaining how previous research had primarily focused on their dramatic demise which followed the asteroid impact some 66 million years ago.
Fossil evidence suggests dinosaurs emerged around 230 million years ago, floating onto the evolutionary scene long before taking center stage. Their development seems rather slow; it wasn’t until approximately 30 million years later, at the onset of the Jurassic Period, when they really began to thrive and taken over numerous ecological niches.
This new research employs the creative use of bromalites, which not only includes feces but also vomit and undigested food remnants found within fossilized intestines. By examining these unique specimens, scientists were able to decode the diets of these ancient creatures. What's more intriguing is how the entire study links dietary habits to the evolution of the species themselves, around the changes through time.
Researchers utilized innovative techniques like synchrotron microtomography, which allowed them to create 3D images of the bromalites. Through this method, they found remains of insects, plants, fish, and even larger creatures within the excrement. For example, analyzing these samples showed signs of plant matter and the remains of smaller animals, offering clues about what these dinosaurs were consuming.
One remarkable discovery came from the investigation of the Silesaurus, considered one of the predecessors to the dinosaurs. While Silesaurus was quite small—about 15 kilograms—it demonstrated significant adaptability by thriving on varied diets including insects, fish, and plants. During periods of environmental shifts, like the Carnian Pluvial Episode—marked by excess rainfall and the blossoming of new plant species—larger herbivorous dinosaurs struggled, but Silesaurus flourished, pointing to the advantages of being opportunistic.
Over the course of the 30 million years studied, the average size of these bromalites increased significantly, coinciding with the growth of their rightful owners. The findings reflect how as dinosaurs and their ecosystems evolved, so did their feeding habits. By juxtaposing the results of the bromalites with existing fossil records, researchers pieced together the development and rise of dinosaurs more coherently.
Intriguingly, the study produces more than just fodder for the imagination; it also speaks to two prevailing theories about dinosaur dominance. Some scientists propose early dinosaurs capitalized on anatomical features—like standing upright and being fast—to outcompete rivals. Others suggest major environmental changes, such as volcanic activity or climatic shifts, cleared the stage for dinosaurs to flourish.
The team's conclusion leans toward a blend of these theories. They hypothesize the dinosaurs used their evolutionary advantages to navigate through these environmental upheavals, allowing them room to thrive at the top of the food chain. Lawrence Tanner, another researcher, noted the study's methodology was creative, yet recognized it faces limitations as it focuses only on Poland's geological basin, which during the Mesozoic was part of the Pangea supercontinent.
Qvarnstrom hopes the developed model can eventually be applied to study other regions, broadening the narrative on how dinosaurs conquered the planet. By connecting diet to evolutionary advantages and environmental changes, this groundbreaking work on laws written not just by bones but by feces and vomit brings new revelations about progression and the resilience of the dinosaurs.
