New species of predatory dinosaur discovered

The fossil remains of a new species of the abelisaurid theropod family, a family of carnivorous dinosaurs, have been found.

The discovery has been made near the city of Plaza Huincul, in the province of Neuquén, Argentina.

The new species has been given the name Elemgasem nubilus and it inhabited the region approximately 90 million years ago.

“Based on histological analyzes of the fossils, we determined that the specimen, a carnivorous biped that ate mainly herbivorous animals, was at least eight years old. He was a sexually mature individual, but he still hadn’t finished growing,” says Mattia A. Baiano, first author of the work that was part of his thesis as a doctoral fellow at the National Council for Scientific and Technical Research (CONICET) of Argentina, under the direction of Rodolfo Coria, at the Paleobiology and Geology Research Institute (IIPG) and the Carmen Funes Municipal Museum.

The specimen of the new species had an approximate length of four meters from head to tail and a height of nearly two meters.

“Elemgasem nubilus was part of a fauna that includes several previously described carnivorous dinosaurs such as Patagonykus, Megaraptor, Neuquenraptor and Unenlagia, all from the same fossiliferous locality,” says Baiano, now a CONICET postdoctoral fellow at the National University of Río Negro ( UNRN) and the “Ernesto Bachmann” Municipal Museum, in Villa El Chocón, in the Province of Neuquén.

They named the new species of dinosaur Elemgasem in reference to the Tehuelche god that bears that name, and nubilus, which in Latin means “cloudy days.” “The fog is rare in the semi-arid climate of Patagonia, but it was very persistent during the days when its fossils were discovered,” explains Baiano.

The Elemgasem nubilus was counted within the main groups of predatory dinosaurs. (Illustration: Abel Germán Montes)

a particular species

Elemgasem nubilus was one of the main predatory groups and was closely related to other abelisaurid theropods from Argentina (Brachyrostra) including species such as Carnotaurus, Aucasaurus and Skorpiovenator.

This family of dinosaurs dominated the carnivorous fauna during the Late Cretaceous (between 100 million and 66 million years ago) of Gondwana, a continent made up of what is now South America, Antarctica, India, Africa, and Australia.

Coria, also director emeritus of the Carmen Funes Municipal Museum, in the city of Plaza Huincul (Neuquén), states: “The identification of a new species is always a scientifically relevant fact, especially if the species belongs to an emblematic family of carnivorous dinosaurs such as the abelisaurs. Elemgasem represents a key piece in the puzzle of the evolution of this group, which began to be assembled with the first findings of José Bonaparte (the most important Argentine vertebrate paleontologist of the 20th century) in the 1980s”.

“We already knew forms of abelisaurs in older horizons (such as the Cenomanian) or more modern (such as the Campanian), so it was predictable that there would be them in between times. What we did not imagine was finding a comparatively small abelisaur like Elemgasem, whose size is clearly smaller than that of the rest of the species of the group such as Carnotaurus, Aucasaurus or Skorpiovenator. Paleohistological studies allowed estimating an early adulthood for the individual at the time of his death. In other words, if he had lived, he would not have grown much more,” adds Coria, who trained as a paleontologist with Bonaparte and is also director of the Paleontology program at the UNRN.

Along these lines, Baiano adds: “The relevance of our work lies, above all, in the fact that Elemgasem nubilus is the first dinosaur of its family to be found in the Portezuelo Formation, which covers a time period of one and a half million years approximately (in the Turonian-Coniacian interval), and thus we increased the diversity of theropod dinosaurs at a time in geological history affected by a marked transformation in the fauna of South America, global climate change and extinction events recorded mass around the world.

Diego Pol, also author of the work and CONICET researcher at the Egidio Feruglio Paleontological Museum, in Trelew (Chubut Province), states: “Every time we face a time in the past of the planet in which there were great extinctions, we ask ourselves why why some species survived and others did not. Is it simply a random factor or do the species that survive usually have some factor in common that explains their survival? The difficult thing is to find the surviving species right at the time of these extinctions, because if we find their descendants ten million years after the extinction we will be seeing species that are already highly modified. I think that Elemgasem gives us a bit of information on this aspect and it will be a fact that in the future will help us understand one of the many partial extinction events that dinosaurs suffered in their history”.

On the other hand, Baiano points out that the finding once again highlights the paleontological importance of the region. “Argentina, and in particular Patagonia, is, together with China, the United States and Canada, one of the most important places in the world in terms of paleontology, given that every year there are multiple new discoveries published in international scientific journals. . Each time we add one more grain of sand to the knowledge of life in the past. And the contribution to this knowledge, which comes from this part of the world made by various paleontology and geology teams in the country, is extremely important.”

The study is entitled “Elemgasem nubilus: a new brachyrostran abelisaurid (Theropoda, Ceratosauria) from the Portezuelo Formation (Upper Cretaceous) of Patagonia, Argentina”. And it has been published in the academic journal Papers in Palaeontology. (Source: CONICET. CC BY 2.5 AR)