Home Biomedical research A strange carnivorous dinosaur joins “Rogues’ G”

A strange carnivorous dinosaur joins “Rogues’ G”


image: Reconstruction of the ecosystem of the Bahariya oasis in the Sahara desert in Egypt around 98 million years ago, showing the diversity of large theropods (predatory dinosaurs). The newly discovered and as yet unnamed abelisaurid (right) confronts Spinosaurus (center left, with fish in its jaws) and Carcharodontosaurus (center right). In the background, a herd of the sauropod (giant long-necked herbivorous dinosaur) Paralititan (left) gazes warily at these predators, while a herd of an as yet unnamed pterosaur (flying reptile) hovers above.
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Credit: Andrew McAfee, Carnegie Museum of Natural History.

ATHENS, Ohio (June 8, 2022) – A team of Egyptian-American researchers has announced the discovery of a new type of large carnivorous dinosaur, or theropod, from a famous fossil site in Egypt’s Sahara Desert. The fossil of a yet unnamed species provides the earliest known record of the abelisaurid theropod group from a mid-Cretaceous (~98 million years old) rock unit known as the Bahariya Formation, which is exposed in the West Bahariya oasis. Desert of Egypt.

At the beginning of the 20e century, this locality provided the original specimens of a host of remarkable dinosaurs, including the colossal sail-backed fish-eater Spinosaurus– which were later destroyed during World War II. Abelisaurid fossils had previously been found in Europe and many continents of today’s Southern Hemisphere, but never before in the Bahariya Formation. The team describes the discovery of the Bahariya abelisaurids in a article published today in Royal Society Open Science.

The study was led by Ohio University graduate student Belal Salem, based on work he initiated while a member of Mansoura University’s Vertebrate Paleontology Center ( MUVP) in Mansoura, Egypt. The research team also included Patrick O’Connor, professor of biomedical sciences at Ohio University’s Heritage College of Osteopathic Medicine; Matt Lamanna, associate curator of vertebrate paleontology at the Carnegie Museum of Natural History; Sanaa El-Sayed, doctoral student at the University of Michigan and former vice-director of MUVP; Hesham Sallam, professor at the American University in Cairo (AUC) and Mansoura University and founding director of MUVP; and other colleagues from Benha University and the Egyptian Environmental Affairs Agency.

The fossil in question, a well-preserved vertebra from the base of the neck, was recovered by an MUVP expedition in 2016 from Bahariya Oasis. The vertebra belongs to an abelisaurid, a kind of bulldog-headed, small-toothed, small-armed theropod that is estimated to have been about six meters (20 feet) in length. Abelisaurids – notably represented by the horned and demonic-looking Patagonian form Carnotaurus of jurassic world and prehistoric planet fame – were among the most diverse and geographically widespread large predatory dinosaurs in the southern landmasses during the Cretaceous Period, the last period of the Age of Dinosaurs. In the same way Spinosaurus and two other giant theropods (Carcharodontosaurus and Bahariasaurus), the new abelisaurid fossil adds another species to the group of large predatory dinosaurs that roamed what is now the Egyptian Sahara around 98 million years ago.

“During the mid-Cretaceous, the Bahariya Oasis would have been one of the most terrifying places on earth,” says Salem, a new student in Ohio University’s biological sciences graduate program. “How all these huge predators managed to co-exist remains a mystery, although it’s probably related to the fact that they ate different things, that they adapted to hunt different prey.”

The new vertebra has implications for the biodiversity of Cretaceous dinosaurs in Egypt and throughout the northern region of Africa. It is the oldest known Abelisauridae fossil from northeast Africa, and shows that by the mid-Cretaceous these carnivorous dinosaurs ranged over much of the northern part of the continent from east to west, from present-day Egypt to Morocco, to the south. such as Niger and potentially beyond. Spinosaurus and Carcharodontosaurus are also known from Niger and Morocco, and a close relative of Bahariasaurus was also found in the latter nation, suggesting that this large to gigantic theropod fauna co-existed across much of North Africa at this time.

How can the discovery of a single cervical vertebra lead researchers to conclude that the fossil belongs to a member of the Abelisauridae, a kind of carnivorous dinosaur that has never been found in the Bahariya Formation before? The answer is remarkably simple: it is virtually identical to the same bone in other better known abelisaurids such as Carnotaurus from Argentina and Majungasaurus from Madagascar. As co-author and Salem graduate advisor Patrick O’Connor, who in 2007 published a comprehensive study of the spinal anatomy of Majungasaurus, explains: “I have examined abelisaur skeletons from Patagonia to Madagascar. My first glimpse of this specimen from photos left no doubt as to its identity. The neck bones of abelisaurids are so distinctive.

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Bahariya Oasis is renowned in paleontological circles for providing the type specimens (the original fossils, first discovered and named after them) of several extraordinary dinosaurs in the early 20e century, including, the most famous, Spinosaurus. Unfortunately, all of the Bahariya dinosaur fossils collected before World War II were destroyed in an Allied bombing of Munich in 1944.

As a graduate student in the early 2000s, study co-author Matt Lamanna helped make the first dinosaur discoveries in the oasis since the infamous 1944 air raid, including the gargantuan sauropod ( long-necked herbivorous dinosaur) paralititan. “Bahariya Oasis has achieved near-legendary status among paleontologists for producing the earliest known fossils of some of the world’s most amazing dinosaurs,” says Lamanna, “but for more than three-quarters of a century these fossils have not only exist as pictures in old books. Fortunately, discoveries made during recent expeditions led by AUC and MUVP researchers, such as the new abelisaurid vertebra, are helping to restore the paleontological legacy of this classic site. These expeditions have recovered a slew of additional fossils that the researchers plan to uncover in the near future.

As team member Sanaa El-Sayed, who co-led the 2016 expedition that collected the abelisaurid vertebra, explains, “This bone is just the first of many important new dinosaur fossils from the ‘Bahariya oasis’.

The Bahariya Formation promises to shed light on Africa’s mid-Cretaceous dinosaurs and the extinct ecosystems they once lived in. Unlike more explored rocks of the same age in Morocco which tend to produce isolated bones, the Bahariya Formation appears to preserve partial skeletons of dinosaurs and other land animals with relatively high frequency. The more bones preserved in the skeleton of a given skeletal fossil species, the more paleontologists can generally learn about it. The propensity of Bahariya Oasis to produce associated partial skeletons suggests that much remains to be learned from this historical locality.

“When it comes to Egyptian dinosaurs, we’ve only scratched the surface,” notes study co-author Hesham Sallam. “Who knows what else might be out there?” Recent efforts by Professor Sallam and his collaborators around the world are placing Egyptian students in leading roles in the research process. The field expedition that recovered the new abelisaurid fossil and follow-up laboratory work were led by MUVP-based student researchers and contributing authors to the paper. “Working with MUVP, its faculty and students, like Belal Salem, continues to inspire me, as I see the next generation of paleontologists playing a leading role in sharing their insights into the history of our planet,” adds O’Connor.

Research on the new abelisaurid vertebra was supported by a field research grant to Matt Lamanna of the National Geographic Society’s Committee for Research and Exploration, grants to Hesham Sallam of Mansoura University, and the intramural grants from the American University in Cairo, and a grant to Patrick O’ Connor from the National Science Foundation (EAR-1525915).

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