Exceptionally preserved skin of Montsecosuchus depereti, an extinct crocodylomorph no larger than a house cat that prowled the tropical wetlands of Early Cretaceous Spain, has allowed paleontologists to reconstruct details of its scales, sensory organs and even possible banded markings along its tail.
The holotype specimen of Montsecosuchus depereti. Image credit: Castillo-Visa et al., doi: 10.1093/zoolinnean/zlag076.
The fossilized skeleton of Montsecosuchus depereti was unearthed in 1902 by the engineer and geologist Lluís Marià Vidal at a quarry in the Noguera region of Catalonia, Spain.
For over a century, the 50-cm-long specimen sat in the collections of the Museum of Natural Sciences of Barcelona.
“Crocodylomorpha — crocodilians and their extinct relatives — have an extensive fossil record that extends from the Late Triassic to the present day,” said Dr. Oscar Castillo-Visa from the Institut Català de Paleontologia Miquel Crusafont at the Universitat Autònoma de Barcelona and colleagues.
“Nevertheless, fossilized soft tissues (e.g. skin and cartilage) are virtually unknown for most clades, with the exception of the marine thalattosuchians.”
Using ultraviolet (UV) light, the paleontologists identified and described a variety of cartilaginous and epidermal tissues in Montsecosuchus depereti, making it one of the most complete and oldest preserved skin specimens among all crocodylomorphs.
“UV light allows us to see details that would otherwise remain completely hidden in the rock,” Dr. Castillo-Visa explained.
The holotype specimen of Montsecosuchus depereti under UV light. Image credit: Castillo-Visa et al., doi: 10.1093/zoolinnean/zlag076.
The researchers found that epidermal scales formed discontinuous patches across Montsecosuchus depereti’s arms, thorax, legs, and tail, with the best-preserved skin appearing on the forelimb and thoracic regions.
They also identified what may be integumentary sensory organs — small, specialized scales on the body’s periphery — suggesting that such organs first evolved in a restricted form before spreading more widely across the bodies of later crocodilians.
These tiny pits, found in abundance on the faces and bodies of modern species, are exquisitely sensitive to pressure and vibration, helping crocodilians detect prey in murky water. Their origin, it seems, was more modest than previously assumed.
“In today’s crocodiles, these organs function as receptors for touch and variations in water pressure, and can also respond to thermal and chemical stimuli,” the scientists said.
Preserved cartilaginous tissues in the thoracic region suggest that Montsecosuchus depereti had adaptations for increased respiratory efficiency.
These bony or cartilaginous projections, found today in birds, help stiffen the rib cage and improve the mechanics of breathing.
Their presence in this ancient species hints at a more active, aerobically capable animal than the sluggish stereotype of modern crocodiles might suggest.
“These traits indicate that, despite being a primitive animal, it was already very well adapted to a semi-aquatic lifestyle,” Dr. Castillo-Visa said.
Montsecosuchus depereti lacked two features characteristic of modern crocodilians: a deep caudal ‘fin’ and strongly keeled scales on the limbs.
In other words, the animal would have had a somewhat smoother silhouette than the Nile crocodile.
The authors also found something more visually striking: evidence of banded coloration along the tail.
That pattern — alternating dark and light bands — is common among living crocodilians and many other reptiles, used for camouflage or species recognition.
Seeing it echoed in a creature from the age of dinosaurs is a small but vivid reminder that evolution is, at times, extraordinarily conservative.
“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,” said Dr. Albert Sellés, a researcher with the Institut Català de Paleontologia Miquel Crusafont at the Universitat Autònoma de Barcelona and the Museu de La Conca Dellà.
The team’s findings were published in the Zoological Journal of the Linnean Society.
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Oscar Castillo-Visa et al. 2026. Soft tissue preservation in the Barremian Montsecosuchus depereti (Neosuchia: Atoposauridae). Zoological Journal of the Linnean Society 207 (2): zlag076; doi: 10.1093/zoolinnean/zlag076
