Plate Nº 31 · recorded October 10, 2026
Biology & EvolutionReported finding
UV Light Reveals Camouflage Pattern on 125-Million-Year-Old Crocodile
UV imaging of a 125-million-year-old crocodile fossil from Spain has uncovered preserved scales, possible sensory organs, and tail bands that may be the oldest known crocodylomorph coloration.
By Priya Raman3 min read627 words
In brief
- Fossil is 125 million years old, from the Lower Cretaceous
- Specimen is 50 centimeters long and cataloged as MGB-512
- Published September 15, 2026 in the Zoological Journal of the Linnean Society
- Pedrera de Meià has yielded more than 8,000 fossil specimens to date
- Over 100 specimens are on display at the Montsec de Meià Interpretation Center in Vilanova de Meià
Ultraviolet imaging of a 125-million-year-old crocodile fossil from northeastern Spain has revealed alternating light and dark bands on its tail that may represent the oldest known preserved coloration in a crocodylomorph.
The 50-centimeter specimen, cataloged as MGB-512, belongs to Montsecosuchus depereti, a small crocodylomorph from the Early Cretaceous. Researchers from the Institut Català de Paleontologia Miquel Crusafont published their analysis on September 15, 2026, in the Zoological Journal of the Linnean Society.
How did UV light reveal hidden anatomy?
The Pedrera de Meià site in Lleida, Catalonia, yielded the fossil more than a century ago. Paleontologists Oscar Castillo and Jesús Serrano noticed hidden structures when they examined it under ultraviolet light while building a database of Montsec lithographic limestone fossils.
UV light causes fossilized tissues and surrounding rock to fluoresce differently, exposing details invisible under normal lighting.
"UV light allows us to see details that would otherwise remain completely hidden in the rock," said first author Oscar Castillo-Visa.
What did the soft tissues show?
The team documented:
- Epidermal scales of varied shape and size across the body
- Absence of the tall caudal fin found in modern crocodiles
- Possible sensory organs inside small scales around the neck, limbs, trunk edges, and tail
- Cartilaginous structures in the chest suggesting an efficient respiratory system
In living crocodiles, similar sensory organs detect touch, water pressure changes, temperature, and chemical signals. Their restricted distribution in Montsecosuchus may indicate that such organs first evolved in localized body areas before spreading across the skin in later crocodylomorph lineages.
"These traits indicate that, despite being a primitive animal, it was already very well adapted to a semi-aquatic lifestyle," Castillo-Visa said.
What do the tail bands suggest?
The most striking finding came from the caudal region. Some scales there show alternating light and dark bands running across the tail. The team interprets these as possible remnants of the animal's original coloration.
The pattern may have functioned as disruptive camouflage, breaking up the crocodile's outline against its surroundings. If confirmed, Montsecosuchus would become the oldest known crocodylomorph with preserved color evidence.
Scientists cannot yet determine the actual colors. The preserved bands show contrast, not hue.
"At the moment we cannot say for sure what color the crocodile's tail was, but it would be expected that it was not so different from current species, which also show different coloration patterns," explained co-author Albert G. Sellés.
Why does this fossil site matter?
Pedrera de Meià is a Konservat-Lagerstätte, a term for fossil deposits with extraordinary preservation. Fine sediments in a karstic pool near the Early Cretaceous coast locked in delicate soft structures that normally decay long before fossilization can occur.
More than 8,000 fossil specimens have come from the site, including:
- Fish, amphibians, and reptiles
- Insects such as spiders, flies, wasps, and beetles
- Crustaceans and insect larvae
- Plant material, including Montsechia, the earliest known flowering plant
The site sits within the UNESCO Orígens Global Geopark. The Montsec de Meià Interpretation Center in Vilanova de Meià displays more than 100 exceptionally preserved specimens to the public.
What are the study's limits?
The researchers flag the coloration interpretation as preliminary. Fluorescence patterns can shift with mineral composition, decay, and preservation conditions. The bands may not directly mirror the original color scheme.
The fossil's 50-centimeter length also means the soft-tissue evidence comes from a small or possibly juvenile individual. The findings may not apply to larger crocodylomorphs of the same period.
The Spanish Ministry of Science, Innovation and Universities, the NextGenerationEU/PRTR program, the Generalitat de Catalunya, and the CERCA program funded the work. Co-authors include Àngel Galobart, director of the Conca-Dellà Museum, and Phil Bell of the University of New England.
via pedrerademeia.geoparcorigens.cat (Original)
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Senior reporter covering industry trends and analytics at SciBeat.
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