Abditosaurus kuehnei: A new exceptionally large dinosaur for its time identified in the Catalan Pyrenees | Catalonia


Reconstruction of the appearance of 'Abditosaurus kuehnei' in life.
Reconstruction of the appearance of ‘Abditosaurus kuehnei’ in life.(Oscar Sanisidro / Conca Dellà Museum.

A new herbivorous dinosaur of the titanosaur family, 18 meters long and weighing 14 tons, has been identified in the Catalan Pyrenees and its description is published today in the journal Nature Ecology & Evolution. baptized as Abditosaurus kuehnei, the animal, a sauropod (the typical phytophagous, plant-eating dinosaur that moved on all fours and had a very long neck and tail), lived in the Late Cretaceous (or Cretaceous) 70.5 million years ago in a landscape very different from the mountains where their remains were found, during a great paleontological adventure, at the Orcau-1 site, in the municipality of Isona i Conca Della, in the Pallars Jussà region (Lleida). In that remote time, Europe was a group of islands, an archipelago, the Pyrenees were just beginning to form (it would take 20 million years) and the sea reached the current site forming a set of beaches, deltas and wetlands with abundant vegetation and forests. .

Around there he wandered to his own Abditosaurus kuehneia titanosaur (“titanic lizard or reptile”) “exceptionally large” for the area and time, according to the researchers who have described the new species: members of the Institut Català de Paleontologia Miquel Crusafont (ICP), the Museo de la Conca Dellà (MCD), the Autonomous University of Barcelona (UAB), the University of Zaragoza (UNIZAR) and the Universidade Nova de Lisboa (UNL).

Abdithosaurus means “forgotten reptile” and the specific epithet kuehne It is a tribute to its discoverer. The name refers to the long history of research that has led to the description of the new species and which dates back to 1954, when the German paleontologist Walter Kühne (1911-1991), known as the legendary explorer of the mammals of the Mesozoic, excavated the first remains and sent them to the Lucas Mallada Institute, in Madrid. The site fell into oblivion -hence the Abdithosaurus– until 1986 when some more remains were removed, but a major storm canceled the excavation. The site was again relegated until in 2012, ICP research staff resumed excavations systematically. And now, the one known generically as “the Orcau titanosaur” has come to have a name, baptizing a new species.

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The titanosaurs are the last representatives -before the mass extinction of the dinosaurs- of the group of sauropods, of which the popular diplodocus of the Jurassic are part. They were the dominant herbivores in the Upper or Late Cretaceous faunas of what is now the Iberian Peninsula and very abundant in the Tremp Basin. The titanosaurs of the Late Cretaceous (100-66 million years ago) were not particularly large, for sauropods and titanosaurs, a family that has given rise to some of the largest known dinosaurs, such as the Argentinosaurus or the Patagonians from the oldest Lower Cretaceous (a 140-100 million years), perhaps up to 40 meters and 70 tons.

Image of the excavation of remains of the new titanosaur.
Image of the excavation of remains of the new titanosaur.

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Among the relatively small titanosaurs of the Late Cretaceous, with some species that did not exceed eight meters, the now baptized Abditosaurus kuehnei appears as a colossus. Its dimensions, experts emphasize, make it in fact the largest species of dinosaur in the Ibero-Armorian domain, the ancient region that currently grouped the current Spain, Portugal and the south of France. One of the aspects that have surprised researchers is precisely its size. “The titanosaurs that we usually find in the Late Cretaceous of Europe tend to be small or medium-sized as a result of having evolved in insular conditions,” explains Bernat Vila, ICP paleontologist who signs the article. A titanosaurian sauropod with Gondwanan affinities in the latest Cretaceous of Europe along with Albert Sellés, Miguel Moreno-Azanza, Novella Razzolini, Alejandro Gil-Delgado, Iñaki Canudo and Àngel Galobart.

During the Upper Cretaceous, paleontologists point out, Europe was an extensive archipelago made up of dozens of islands. The faunas that evolved there tend to be small or even dwarf forms due to the food limitation of living on an island. “It is a recurring phenomenon in the history of life on Earth and we have many examples in the fossil record. That is why we were surprised by the large dimensions of this specimen”, says Vila, who was able to consult Kühne’s original field notebooks, keys to understanding that the remains that the German began to excavate in 1955 and those recovered later correspond to the same specimen.

The remains of this dinosaur that until now had no name, the most complete titanosaur skeleton in Europe, consist of various vertebrae and ribs of the trunk and bones of the limbs and the pelvic and shoulder girdles, but a semi-articulated fragment of five meters stands out especially of the long neck formed by 12 cervical vertebrae, some fused together. “We are rarely lucky enough to find such complete specimens,” explains Galobart, ICP researcher, director of the Conca Dellà Museum (in Isona) and author of the article.

In the different excavation campaigns, up to 53 remains of the animal’s skeleton have been recovered, embedded in a large vertical wall. “The skeletal fossils of Abdithosaurus they can be seen in the new Conca Dellà Museum, which is scheduled to be inaugurated during the first quarter of this year”, emphasizes Galobart.

The spectacular excavation of the neck in 2014 was a technical challenge, since a “mummy” had never been extracted – the term used in paleontology to refer to the block of polyurethane foam that protects the fossil inside – of these dimensions in Europe.

Excavation work of parts of the fossil.
Excavation work of parts of the fossil.

The article published today in the magazine Nature Ecology & Evolution includes interesting phylogenetic analyzes (that is, of kinship) of the new species and concludes that Abdithosaurus It belongs to a group of saltasaurine titanosaurs (after the Argentine town of Salta) from South America and Africa, separated from the rest of European dinosaurs that are characterized by a smaller size. The research staff proposes that the lineage of Abdithosaurus It reached the Iberian-Armorian island and the current Pyrenees, taking advantage of a global drop in sea level that allowed the reactivation of ancient wildlife migration routes between Africa and Europe. “There is other evidence that supports the migration hypothesis”, explains Albert Sellés, a paleontologist at the ICP and also a co-author of the article. “In the same site we have found eggshells of dinosaur species that we know inhabited Gondwana, the southernmost continent.”

Abdithosaurus, The researchers emphasize represents a fundamental advance in the knowledge of the evolution of sauropod dinosaurs at the end of the Cretaceous and provides a new perspective to the phylogenetic and paleobiogeographical puzzle of these animals in the last 15 million years before their extinction

The skull of titanosaurs as Abdithosaurus, paleontologists explain it was small and pointed, with small nail-shaped teeth that were used to uproot vegetation. They had a robust body, with legs similar to those of elephants, the front ones shorter than the back ones, and a relatively long neck and tail. Some species, including many of those found fossilized in the Pyrenees, had their trunks covered with unusual bony plates called osteoderms. It is believed that these structures could serve as defensive armor (although not complete like that of ankylosaurs), or perhaps as a reserve of calcium for the animal.

The Pyrenees, experts point out, are exceptional in terms of the fossil record of dinosaurs; they are very well represented and include the last species that lived in Europe. The collaboration between the ICP and the University of Zaragoza over the last 20 years “has made it possible to recognize a unique and previously unknown biodiversity at the end of the Cretaceous, shortly before they disappeared throughout the world 66 million years ago”.

An excavator works on the enclave where a group of researchers has found a sauropod neck more than 5 meters long.Video: Catalan Institute of Paleontology Miquel Crusafont


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George Holan

George Holan is chief editor at Plainsmen Post and has articles published in many notable publications in the last decade.

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