Europe’s First Jurassic Lizard Trackways Discovered — What Was This Ancient Reptile Doing One Hundred Fifty-Two Million Years Ago?
For decades, paleontologists have searched for clear evidence of small reptile activity during the Late Jurassic period in Europe. Dinosaur footprints are abundant across the continent, yet traces left by smaller reptiles remain extremely rare. Now, a remarkable discovery from northern Spain has begun to fill that gap. Researchers have documented what appears to be Europe’s first confirmed Jurassic lizard trackways, preserved in coastal rock formations in the region of Asturias.
The research results were published online in late February in the scientific journal Ichnos. The study describes two fossilized trackways preserved on the underside of a sandstone layer dating to roughly one hundred fifty-two million years ago, during the Late Jurassic period. These remarkable footprints were discovered in cliffs east of Playa de España in the municipality of Villaviciosa. Today, the specimens are preserved in a museum collection and displayed in a gallery dedicated to the Jurassic heritage of Asturias.
But how did these tiny tracks survive for more than one hundred fifty million years? And what can they tell us about reptile life during the age of dinosaurs?
Jurassic Lizard Trackways in Asturias Reveal Rare Fossil Evidence
The newly described trackways are preserved as convex hyporeliefs, meaning the footprints appear raised on the underside of a rock layer rather than indented on the surface. This type of preservation often occurs when mud impressions are filled with sediment that later hardens into stone.
Both trackways display distinct anatomical features. The hand and foot impressions vary between four-toed and five-toed forms. Moreover, they are slightly asymmetrical, and the toes gradually increase in length from one side to the other. Because of these characteristics, scientists were able to attribute the tracks to a lizard and classify them within the ichnogenus Rhynchosauroides.
This classification is particularly intriguing. Fossils assigned to Rhynchosauroides were widespread during the Permian and Triassic periods. However, they become extremely rare in the Jurassic fossil record. As a result, the Asturian tracks represent the youngest known occurrence of this track type anywhere in the world.
Could this discovery indicate that certain reptile lineages survived longer than previously believed? Or might it suggest that paleontologists have simply overlooked similar traces elsewhere?
Footprints of Two Jurassic Lizards Preserved for One Hundred Fifty-Two Million Years
The first trackway, labeled T-one, consists of seven distinct impressions. Four represent handprints, while three correspond to footprints. Based on the spacing and size of the tracks, researchers estimate that the animal responsible measured approximately fifty centimeters in length.
The second trackway, labeled T-two, contains six impressions in total. These include three handprints and three footprints. This set likely belongs to a slightly smaller individual, measuring around thirty centimeters long.
Despite their small size, these reptiles left surprisingly clear marks in the ancient sediment. The preservation quality allowed scientists to study details of locomotion and posture with unusual precision.
Interestingly, the first trackway reveals another unexpected feature.
Tail Drag Mark in Jurassic Lizard Trackways Suggests Unique Movement
In trackway T-one, researchers identified a nearly continuous structure running along the path of the footprints. The structure appears wide, straight, and only slightly raised above the surrounding surface. After careful analysis, scientists interpreted this feature as a tail drag mark.
Tail drag traces are relatively rare in reptile trackways. Their presence can reveal valuable information about how an animal moved. For example, a dragging tail might indicate slow movement, a shift in posture, or a moment of imbalance.
However, another puzzling pattern appeared in the same trackway. The distance between the handprints and footprints varied significantly along the path. Instead of forming a regular walking pattern, the trackway displayed a highly irregular gait.
Why would a small Jurassic reptile move in such an uneven way?
Modern Lizard Experiments Help Explain Jurassic Trackway Patterns
To understand the unusual track pattern, researchers conducted a series of experiments using living reptiles. The team studied two modern species: the Ocellated Lizard and the Bearded Dragon.
The tests were designed to be entirely non-invasive. Captive specimens were observed in a research facility located in Jiangyin, a city in China’s Jiangsu province. By allowing the animals to move naturally across soft surfaces, scientists recorded the footprints they produced.
The results were illuminating.
When these lizards began moving from a stationary position, especially juvenile individuals, they often performed abrupt turns or sudden directional changes. During these moments, the animals produced trackways that closely resembled the irregular patterns seen in the Asturian fossils.
Therefore, the ancient trackmaker may have been doing something similar. Perhaps it was startled by a nearby predator. Perhaps it was chasing prey. Or perhaps it simply shifted direction while beginning to move.
Each footprint captures a moment of behavior frozen in deep time.
Late Jurassic Coastal Environments Helped Preserve Lizard Footprints
The environment in which these tracks formed also played a critical role in their preservation. During the Late Jurassic, the region that is now Asturias contained delta systems that emptied into a shallow inland sea.
At the time, the sea experienced little or no tidal influence. Furthermore, a natural barrier separated it from the open ocean, protecting the coastline from strong waves. As a result, muddy sediments accumulated in calm conditions.
When the lizards walked across this semi-consolidated mud, their footprints pressed into the soft surface. Shortly afterward, new layers of sediment covered the impressions. Over millions of years, these layers hardened into sandstone, locking the tracks into the rock record.
Without such quiet environmental conditions, the delicate prints would likely have vanished within hours.
Why Jurassic Lizard Trackways Are So Rare in the Fossil Record
One question naturally arises from this discovery: why are lizard footprints from the Jurassic so uncommon?
Several factors may contribute to their rarity. First, small reptiles exert far less pressure on the ground than large dinosaurs. Their tracks are therefore less likely to leave deep, lasting impressions. Second, fragile prints can easily be erased by wind, water, or other animals.
Finally, paleontologists may simply overlook them. Small trackways often blend into surrounding rock surfaces and require careful examination to detect.
The Asturian specimens therefore represent more than a regional discovery. They offer a rare window into the daily movements of small reptiles living alongside dinosaurs more than one hundred fifty million years ago.
A Tiny Walk Through Deep Time
The discovery of these trackways raises fascinating questions about Jurassic ecosystems. What other small reptiles lived along these ancient coastlines? How did they interact with the towering dinosaurs that dominated the landscape? And how many other trackways remain hidden within the cliffs of Europe?
Each footprint is a fleeting moment preserved across geological time. A lizard walked across soft mud beside a quiet inland sea. Seconds later, the tide of sediment buried its tracks. Millions of years passed. Continents shifted. Mountains rose.
Yet those tiny steps remain.
What other forgotten journeys might still be waiting beneath the stone?
Source: Europe’s First Jurassic Lizard Trackways Discovered — What Was This Ancient Reptile Doing One Hundred Fifty-Two Million Years Ago?
Europe’s First Jurassic Lizard Trackways Discovered — What Was This Ancient Reptile Doing One Hundred Fifty-Two Million Years Ago?
Sources
The scientific journal Ichnos
Research on Jurassic trackways from Asturias published in Ichnos
Paleontological studies of reptile ichnofossils and the ichnogenus Rhynchosauroides
- Comparative locomotion experiments with the Ocellated Lizard and Bearded Dragon