Abditosaurus kuehnei. Image credit: Oscar Sanisidro / Museu de la Conca Dellà
Towards the end of the Cretaceous, France, Spain and Portugal formed the Ibero-Armorican Island. This region holds one the most complete sauropod dinosaur communities and provides clues to understand the events that differentiate the Ibero-Armorican vertebrate assemblages from those of other European islands. The recently described Abditosaurus kuehnei from the Late Cretaceous of Catalonia is the most complete titanosaur skeleton discovered in Europe so far. The new taxon support the migration hypothesis and shed new light on the palaeobiogeographic events between the European archipelago and Godwana.
Abditosaurus reached 17,5 meters in length (57 ft) with a body mass of 14,000 kg. The holotype, an associated, semi-articulated, partial skeleton, includes several isolated teeth, 12 cervical vertebrae, 7 dorsal vertebrae, 3 chevrons, scapular and pelvic bones, right tibia, parts of the femurs and a complete humerus. The new specimen exhibits an unusual combination of characters not seen in other Ibero–Armorican titanosaurs, like a very robust humerus with a distally expanded deltopectoral crest, a synapomorphy of Saltasauridae. The generic name is derived from the Latin word ‘Abditus’ (means forgotten), and the Greek word “sauros” (lizard). The specific name ‘kuehnei’ honours Professor Walter Georg Kühne who discovered the specimen.
Fossil elements of Abditosaurus kuehnei collected during the 2012-2014 excavations. Image credit: Rubén Contreras. From Vila et al., 2022.
Phylogenetic analyses indicates that Abditosaurus is a saltasaurid lithostrotian titanosaur. Saltasaurinae, a clade from South America and Africa, includes Neuquensaurus, Saltasaurus and Paralititan. The arrival of Abditosaurus to Europe via a dispersal event from Africa ocurred after a regressive event during the Early Maastrichtian(70.6 Ma) that affected the central Tethyan margin and northern Africa.
The history of Abditosaurus began in 1954. Walter Kühne, one of the most renowned specialists on fossil mammals in Europe, found the bones near Orcau (Tremp Basin, Catalonia, Spain), and sent to the Instituto Lucas Mallada in Madrid. In 1955, Kühne revisited the site and collected ten more bones. Unfortunately, the site fall out in oblivion until 1986. when a team led by Josep Vicenç Santafé from the Institut de Paleontologia de Sabadell (Barcelona) found part of a sternal plate and three dorsal ribs. Between 2012 to 2014, a team from the Institut Català de Paleontologia, the Universidad de Zaragoza, and the Museu de la Conca Dellà re-excavated the locality and recovered the remaining axial and appendicular elements. Finally, after 6 decades, the sauropod discovered by Kühne was completely collected in 2014.
References:
Vila, B., Sellés, A.G., Moreno-Azanza, M., Razzolini, N.L., Gil-Delgado, A., Canudo, J.I., Galobart, À. Nature Ecology & Evolution (2022). DOI: 10.1038/s41559-021-01651-5.
Fondevilla, Victor, et al. Chronostratigraphic synthesis of the latest Cretaceous dinosaur turnover in south-western Europe. Earth-Science Reviews (2019) https://doi.org/10.1016/j.earscirev.2019.01.007
Letters from Gondwana. 