World's oldest ceropode has been found: A 165-million-year-old femur
The discovery of a fossilized femur belonging to a cerapodan dinosaur has caused a stir, mainly because of its great age. The discovery team credits the fossilized partial left femur for rewriting the timeline of cerapodan evolution.
Many dinosaur fans have heard of Tyrannosaurus, Velociraptor, and the famed Triceratops. Few people, however, know about the Cerapoda, a group of plant-eating dinosaurs that once included creatures as varied as duck-billed hadrosaurs and horned ceratopsians. The new fossil find from Morocco may change that.
Dr. Susannah Maidment, a paleontologist with the Natural History Museum, London, and the University of Birmingham, contributed to the analysis and presented an in-depth look at the significance of this dinosaur fossil.
Uncovering a hidden dinosaur chapter
Scientists have known cerapodans existed during the Late Jurassic Period and beyond, but older specimens were scarce.
This new partial femur is about 165 million years old, making it the earliest body fossil of a cerapodan ever documented.
Paleontologists spotted unique features on the femur that matched traits seen only in cerapodans. They identified its distinct femoral head and trochanter arrangement, which suggests this dinosaur belongs in the same lineage as hadrosaurs and ceratopsians.
“Cerapoda is a diverse clade of ornithischian dinosaurs with a global distribution,” said Dr. Maidment.
Why it matters
Some of the footprints left in Middle Jurassic rocks belong to cerapodans, indicating that they existed at that time.
Yet the dinosaur fossils have mostly remained elusive. Now, a well-dated femur supports the idea that these dinosaurs had branched out sooner than once believed.
This single bone is important for another reason. It could fill in gaps about early cerapodan adaptations such as stance, limb structure, and herbivorous feeding strategies, which shaped the success of later forms.
Confirming the fossil femur’s age
Scientists examined the rock layers from the region. They used established geological markers to link the deposit to the Middle Jurassic, specifically around 165 million years ago.
They then compared that data with previous knowledge of dinosaur-bearing rock layers, worldwide, to confirm the femur’s antiquity.
Paleontologists also matched the bone’s shape to known cerapodan traits. They ruled out earlier, or more primitive, ornithischians by analyzing the femoral head and trochanteric region.
Their results support this dinosaur’s place among the cerapodans.
Hoping for more dinosaur fossil finds
Experts suggest this find may be just the start. As field teams continue to search underexplored strata in Morocco, more remnants of dinosaurs from the same era may emerge.
Hopes run high that better-preserved fossils will be discovered. Then scientists can figure out how these dinosaurs evolved from lean, bipedal ancestors into large-bodied herbivores with remarkable jaw structures.
Connecting the dots
Ornithischian dinosaurs, which include cerapodans, are recognized for having a hip structure distinct from other dinosaur groups. Their broad distribution hints at early adaptability in numerous environments worldwide.
But many segments of cerapodan history remain poorly understood.
Each fossil from the Middle Jurassic helps scientists piece together their branching family tree, and bridges the gap between smaller, older ornithischians and the famous giants that came later.
Fresh insights on dinosaur diversity
The Moroccan femur gives a rare glimpse into dinosaurs that laid groundwork for entire herds of plant-eaters in the Cretaceous.
Researchers see these early cerapodans as nimble browsers that paved the way for the robust quadrupeds of later ages.
The new evidence also suggests multiple herbivorous lineages diversified simultaneously. That might explain why cerapodans, alongside other plant-eating groups, grew so common in certain ancient ecosystems.
Beyond the fossil femur
Paleontologists note how a single fossil can answer questions about dinosaur dispersal. North Africa likely served as a corridor for many species, showing how some lineages reached global prominence by the Late Jurassic.
Though naming a new species from one fragment is impossible, the fossil stands as a teaser. Further excavations could reveal a fossilized skeleton with jaws, spine, or limb bones that clarify how these dinosaurs thrived in shifting environments.
Bridging evolutionary gaps
This earliest-known cerapodan challenges assumptions about the tempo of dinosaur evolution. Until recently, the group’s best-dated fossils were usually found in younger rocks.
The gap between the earliest cerapodans and their later, more famous relatives had proved a mystery.
A femur alone does not tell the whole story. Yet it indicates that cerapodan dinosaurs were expanding long before the Late Jurassic, and it pushes their known origins far deeper back in time.
Dinosaur behavior and biology
Cerapodans likely shared early traits like bipedal posture. Some later subgroups became quadrupeds, and evolved specialized jaws for processing tough vegetation.
How they shifted their limb posture and feeding methods remains one of paleontology’s key puzzles.
Continued study of limb bones could reveal transitional features. It might even show how rapidly cerapodans increased in size compared with their ancestors.
Bigger picture of Jurassic ecosystems
Each new fossil offers a snapshot of environments that existed roughly 165 million years ago. This cerapodan bone indicates that certain ecological niches were already available to specialized plant-eaters at that time.
Paleontologists see the Middle Jurassic as a stage of experimentation among dinosaur lineages. The Moroccan femur provides evidence that these animals were more widespread and varied than previously thought.
The study is published in Royal Society Open Science.
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