Fossilized remains found in Patagonia, Argentina back in 2009 represent a new genus and species of plant-eating dinosaur that belonged to a group called Rebbachisauridae.
Campananeyen fragilissimus. Image credit: Fundación Azara.
The newly-discovered dinosaur species lived in Patagonia between 99 to 96 million years ago (Late Cretaceous epoch).
Dubbed Campananeyen fragilissimus, the ancient plant-eater was an early member of Rebbachisauridae, a group of diplodocoid sauropods that diversified primarily on the supercontinent Gondwana between the Early and Late Cretaceous.
“Rebbachisauridae is recovered as the basal-most group of Diplodocoidea,” said Dr. Lucas Lerzo, a paleontologist with the Fundación Azara – Universidad Maimónides and CONICET, and his colleagues.
“Although the inferred origin of diplodocoid sauropods is in the Late Lower to Early Middle Jurassic, it is not until the Lower Cretaceous that rebbachisaurid sauropods appear in the fossil record, with a peak of diversity at the end of the history of the family in the Early Upper Cretaceous.”
“Rebbachisauridae is characterized by a highly pneumatized skeleton which deeply invades the axial skeleton and the pelvic girdle.”
“They present novel features in the dorsal vertebrae not reported in any other sauropod.”
The postcranial remains of Campananeyen fragilissimus were collected in 2009 from the Candeleros Formation in Barda Atravesada de Las Campanas, Neuquén Province, Argentina.
They were found along with the fossils of small theropod and rebbachisaurid dinosaurs, a turtle and a lizard.
The team’s analysis shows that Campananeyen fragilissimus is closely related to Zapalasaurus, Sidersaura and a specimen from the La Amarga Formation.
“The new rebbachisaurid is recovered as the sister taxon of Sidersaura due the presence of procoelous posterior caudal vertebrae and dorsoventrally flattened posterior caudal centra,” the researchers said.
“Campananeyen fragilissimus presents an extreme pneumatization of the sacral region with an autapomorphic dorsal alar arm of the sacral transverse processes.”
“Finally, the phylogenetic analysis supports a South American origin for Rebbachisauridae and an early diversification to Africa and Europe by the Barremian-Aptian as previously suggested.”
The discovery of Campananeyen fragilissimus is reported in a paper in the journal Historical Biology.
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Lucas N. Lerzo et al. They all floated in the cretaceous: new rebbachisaurid (Sauropoda, Diplodocoidea) with a highly pneumatized skeleton from the Upper Cretaceous (lower Cenomanian) of Patagonia, Argentina. Historical Biology, published online August 13, 2024; doi: 10.1080/08912963.2024.2383708
