A strange dinosaur, judging by its tracks

Detailed analysis of the footprints left by the dinosaur revealed an unusual trait with which this person was born.

A team led by researchers from the Autonomous University of Madrid (UAM) in Spain analyzed the footprints of a carnivorous dinosaur with toes equipped with sharp nails. The relic was found at the lower Cretaceous site of Las Hoyas, in Cuenca, Spain. It’s an unusually wide track in which the left footprint shows that one of the dinosaur’s feet has a deformity.

The number of dinosaur tracks that formed from diseased feet known to date for a time period of about 125 million years (between the early Jurassic and late Cretaceous) does not reach fifteen in total.

The new analysis, conducted over consecutive years since 2010, ended after recording a large number of pathways until it was confirmed that it was a pathway produced by an animal with a disease.

The organism that produced the footprints, a carnivorous theropod dinosaur, had a hip height of about 2 meters and an estimated length of between 6 and 7 meters. Its healthy footprint is characteristic of the carnivorous dinosaur, with pointed toes, and it measured about 45 cm in length from the tip of its longest toe to the heel. On the other hand, his deformed foot measures 35 cm and has a somewhat irregular shape, highlighting the inner part of his foot, the turn and his short toes.

“The track has a unique feature for theropods, which are bipedal animals. Contrary to typical traces known in the fossil record, the distance between the left and right footprint is very wide,” says Angela D.

In the foreground, a normal footprint in the study trace object. (Photo: UAM)

Pathological pathway analysis, comparing it to a sample of dozens of dinosaurs recorded in global sediments, shows that, despite its breadth, it was caused by a single animal rather than by two that walked in parallel. In addition, they found that the steps taken by the dinosaur were shorter compared to those observed so far on known tracks.

On the other hand, studying the polished layers of sediment where the dinosaur trampled has shown that it is made up of a microbial mat, a thin layer made up of a dense community of algae and bacteria. The flexibility and consistency of this mat allowed it to cement and preserve the details of the footprints and other marks of animals that were in the pond, as well as the growth of the mat itself.

The physical properties of the carpet supported the weight of an animal of tons without breaking, as I was able to study some of the signs left by its movement in detail such as the claws and the depth of the tracks. To analyze these details, three-dimensional scanning of the tracks, as well as the surface of the substrate, was carried out, which allowed us to identify the directions of the marks left by the mat, as well as the undulating paths left by the fish fins.

An interdisciplinary group made up of specialists in dinosaur footprints from the Institute of Geology and Mining in Spain, in fish and invertebrate footprints from the University of Barcelona, ​​and in microbial ecology from the Autonomous University of Madrid, coordinated by the Task Force of the Paleontology Unit and Center for Integration in Paleobiology (CIPb) ) of the Autonomous University of Madrid.

To conduct the study, it was necessary to use different methodologies, and numerical data derived from 3D scanning were necessary to work with many details, both qualitative and quantitative. The data regarding the shape of the trace was obtained by applying the geometry methodology, which has already been tested in a pioneering manner for footprints by some members of the research team.

Differential analysis of this theropod’s pathology indicates a deformity of its inner finger that would bend backwards as occurs in some modern birds. It is not surprising to assume that evolutionarily close groups such as dinosaurs and birds also shared common anomalies. In birds with this deformity, the width between the legs is also larger.

says Carlos M. Herrera-Castillo, Researcher in the Paleontological Unit at UAM. “On the other hand, it is also important to know the context, because it would be a large animal walking through the wetlands at a time when the mats were disintegrating and fish were accumulating in the ponds, perhaps hundreds, due to the great abundance of traces they left.

To date, this theropod is the largest dinosaur ever recorded at the Las Hoyas site, since Pelecanimus polyodon and Concavenator corkovatus are much smaller and the anatomy of their feet could never allow the impression of footprints like those analyzed in the new studio.

The study is titled “Theropod Path Provides Evidence for a Pathological Foot from the Exceptional Region of Las Hoyas (Upper Parmian, Serrania de Cuenca, Spain)”. It has been published in the academic journal PLoS ONE. (Source: UAM)

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