A recent paleontological find in Morocco's Middle Atlas Mountains has taken the scientific community by storm, unveiling the oldest known plant-eating cerapodan dinosaur and pushing back the record of this vital herbivorous lineage by over two million years.

Ancient Fossil Found in the Bathonian Era

An international team of researchers has reported the discovery of a fossilized femur in the El Mers III Formation, a significant Jurassic rock bed in Morocco, dating back approximately 168 million years to the Bathonian stage of the Middle Jurassic. This remarkable find marks a milestone as the oldest skeletal evidence of a cerapodan dinosaur ever documented.

Cerapodans were small, bipedal herbivores classified in the ornithischian group—often referred to as “bird-hipped” dinosaurs. They are closely related to notable genera like iguanodons and hadrosaurs and thrived especially during the Cretaceous Period. Until now, solid evidence of their existence in earlier geological periods was largely missing from the fossil record.

Anatomical Features Confirm Dinosaur Classification

While previous evidence of Middle Jurassic cerapodans was primarily based on fossilized footprints—furnishing merely indirect evidence—the newly discovered femur offers critical clarity. Although fragmentary, this fossil exhibits key characteristics of cerapodans:

- A unique groove on the posterior surface of the proximal end of the femur

- An offset femoral head that connects to a distinctly defined neck

- A narrowing between the head and the greater trochanter

These anatomical features not only solidify its identity as a cerapodan but also eliminate the possibility of misclassification within other neornithischian groups. The interdisciplinary research team, comprising experts from the Natural History Museum (UK), University of Birmingham, and Sidi Mohamed Ben Abdellah University in Morocco, published their findings in the esteemed journal Royal Society Open Science.

Morocco: A Dinosaur Fossil Treasure Trove

The find is particularly exciting as it comes from the same location that previously yielded the world's oldest ankylosaur, along with some of the earliest known stegosaurs—famous for their characteristic dorsal plates. As a result, the El Mers III Formation is emerging as a hotbed for Jurassic biodiversity, marking Morocco as a crucial player in understanding the diversification and evolutionary patterns of early dinosaurs, especially ornithischians.

A Shift in Evolutionary Timelines and Global Context

Before this significant discovery, the previous record-holder for the oldest cerapodan was a femur from the UK dated roughly two million years younger than the Moroccan specimen. This new timeline suggests that cerapodans diversified much earlier than previously accepted, providing a more substantial basis for evolutionary theories that were once founded on incomplete data.

Excitingly, this discovery synchronizes with another recent paleontological feat: in 2024, researchers in China unearthed Archaeocursor asiaticus, recognized as the oldest and most primitive ornithischian in Asia, dating back to 193 million years. Such finds significantly broaden our understanding of the geographical distribution of early ornithischians.

Opening New Chapters in Jurassic Research

This fossil discovery does not merely add another entry to the history of dinosaurs; it reshapes our comprehension of the evolutionary journey of some of the most successful plant-eating dinosaurs. As paleontologists continue to excavate Morocco's fossil-rich terrains, we can expect even more revelations about ancient species that played critical roles in the ecosystems of the Jurassic age.

Stay tuned, as the world of paleontology uncovers more historical marvels that could dramatically change our understanding of the past!