Traces of coloration and a complex respiratory system were found in an ancient crocodile 125 million years old

Paleontologists for the first time described the soft tissues of the ancient crocodylomorph Montsecosuchus depereti, finding traces of its original coloring and signs of a developed respiratory system. The study was published in the Zoological Journal of the Linnean Society and was carried out by specialists from the Miquel Crusafont Institute of Paleontology (Catalonia, Spain).

The fossil, about 125 million years old, was found more than a century ago in the Pedrera de Mea quarry in the province of Lleida - it is kept in the Natural Sciences Museum of Barcelona. The length of the animal was about 50 cm. Although the species has been known since the beginning of the 20th century, it was only now possible to study its soft tissues in detail, using ultraviolet light, under which the fossilized tissues become visible against the background of the surrounding rock.

Paleontologists Oscar Castillo and Jesus Serrano discovered these structures by accident while working on a fossil database from the Montsec lithographic limestones. Under UV light, the researchers saw the epidermal scales - it turned out that their shape and size varied greatly in different parts of the body, and the ancient species did not have the high caudal fin characteristic of modern crocodiles.

Some scales, especially on the neck, limbs and sides of the body and tail, contained inclusions that may indicate sensory organs - in modern crocodiles such receptors respond to touch, changes in water pressure, as well as thermal and chemical stimuli. The fact that in Montsecosuchus they are located only in individual small scales on the periphery of the body may indicate that these structures first appeared in local zones and only later spread throughout the body in later species.

The study also revealed cartilaginous structures in the thorax, suggesting that early in the evolution of crocodylomorphs some of them had complex chest anatomy and an efficient respiratory system, similar in some features to modern crocodiles.

The most unexpected discovery was traces of coloration on the tail - light and dark transverse stripes, which the researchers interpret as a fragment of the original color pattern of the animal. According to scientists, such a pattern could serve as a camouflage, breaking up the silhouette of the body. The authors emphasize that it is not yet possible to say exactly what color the tail was, but they admit that it was not very different from the color of modern species of crocodiles. If the interpretation is confirmed, Montsecosuchus depereti will be the oldest known crocodylomorph with preserved traces of coloration.