168 Million-Year-Old Dinosaur Fossil Discovered in Morocco Reveals Cerapodan Evolution Secrets
A 168 million-year-old dinosaur fossil discovered in Morocco is reshaping our understanding of cerapodan evolution.
In a groundbreaking discovery, a team of paleontologists from the Natural History Museum (U.K.), University of Birmingham (U.K.), and Sidi Mohamed Ben Abdellah University (Morocco) have uncovered the oldest known cerapodan ornithischian dinosaur fossil to date. Published in the journal Royal Society Open Science, this discovery provides new insights into the evolution of early herbivorous dinosaurs. The fossil, a fossilized femur, was unearthed in the Middle Atlas Mountains of Morocco and is estimated to be around 168 million years old, pushing back the previous record by nearly 2 million years. This remarkable find sheds light on a pivotal period in dinosaur evolution and the development of early plant-eating species.
The Significance of Cerapodan Dinosaurs
Cerapodans belong to the group of dinosaurs known as ornithischians, a term that refers to their bird-like hip structure. These dinosaurs were herbivorous and relatively small compared to other prehistoric species. Characterized by their ability to walk on two legs, much like modern birds, cerapodans were crucial to the diversification of plant-eating dinosaurs during the Middle Jurassic. While the Cretaceous period is famous for the widespread existence of cerapodans, the knowledge of their early existence was limited due to a scarcity of fossils from the Middle Jurassic.
The discovery of this fossilized femur is a significant addition to the understanding of early cerapodans and their ecological role. Prior to this, much of the information about them was drawn from fossilized trackways, which only provided limited insight into their physical characteristics. The fossil from Morocco offers a rare glimpse into the anatomy and early evolution of cerapodans, which were later able to adapt to different climates and environmental conditions worldwide.
The Discovery: A Key Fossil from the Middle Jurassic
The discovery took place in the El Mers III Formation, an area renowned for its Bathonian rock deposits. The fossilized femur was found in a layer of rock that had previously yielded the world’s oldest ankylosaur fossil. The femur is distinctly cerapodan in shape, with unique grooves on the back of the top of the femur and a characteristic head shape that sets it apart from other dinosaur species.
The team led by Prof Masato Sakai recognized the fossil as belonging to a cerapodan ornithischian due to these distinct anatomical features. After careful analysis, they dated the fossil to around 168 million years ago, making it the oldest cerapodan fossil ever discovered. This places the cerapodan’s evolutionary timeline much earlier than previously thought, suggesting that the diversification of herbivorous dinosaurs occurred much earlier than once believed.
The fossilized femur’s discovery offers crucial evidence that cerapodans began to diversify before the Cretaceous period, a time when their descendants became widely spread across the globe. This earlier diversification likely played a role in the ability of cerapodans to adapt to various environmental conditions, enabling them to thrive in different regions and during different periods.
Understanding Cerapodan Evolution
The Middle Jurassic period, spanning roughly from 174 to 163 million years ago, represents a time of profound ecological change and the gradual rise of new dinosaur species. The discovery of this femur adds an important piece to the puzzle of early cerapodan evolution. Previously, much of the evidence for cerapodans came from trackways, or footprints, preserved in ancient sediments. These trackways were useful in understanding the movement patterns of these dinosaurs but provided limited information about their physical traits, diet, and ecological niche.
The femur found in Morocco offers a body fossil that reveals much more about the cerapodans’ anatomical structure. The groove on the femur, a distinguishing feature of cerapodans, provides evidence of their evolutionary development. It supports the idea that these dinosaurs were small, plant-eating creatures that were adapted to move on two legs. Additionally, the fossil supports the hypothesis that cerapodans were well-established as a distinct group of dinosaurs long before the Cretaceous period.
With this discovery, researchers are now able to piece together a more detailed picture of the diversification and adaptation of these early herbivorous dinosaurs. The Bathonian period appears to have been a critical time in the development of cerapodans, allowing them to thrive and evolve into the more familiar species we associate with the later Jurassic and Cretaceous periods.