![\"Joaquinraptor](\"https:\/\/cdn.sci.news\/images\/enlarge13\/image_14239e-Joaquinraptor-casali.jpg\")
<\/a><\/p>\nJoaquinraptor casali. Image credit: Andrew McAfee, Carnegie Museum of Natural History.<\/p>\n
The new dinosaur species lived in what is now Patagonia, Argentina, during the latest part of the Cretaceous period, between 70 and 67 million years ago.<\/p>\n
Dubbed Joaquinraptor casali, the ancient predator was a top predator in the region.<\/p>\n
It belonged to Megaraptora, a group of large-clawed carnivorous theropod dinosaurs known from Cretaceous deposits in Asia, Australia, and especially South America.<\/p>\n
\u201cMegaraptorans were carnivorous theropod dinosaurs with elongated skulls and powerful forearms with large claws found across Asia, Australia and South America,\u201d said Dr. Lucio Ibiricu, a paleontologist at the Instituto Patag\u00f3nico de Geolog\u00eda y Paleontolog\u00eda and the Universidad Nacional de la Patagonia San Juan Bosco, and colleagues.<\/p>\n
\u201cHowever, our understanding of this group is hindered by the lack of complete fossils.\u201d<\/p>\n
A well-preserved and partially articulated skeleton of a single Joaquinraptor casali individual was found in the Lago Colhu\u00e9 Huapi Formation of south-central Chubut Province in central Patagonia, Argentina.<\/p>\n
The specimen included much of the dinosaur\u2019s skull, fore and hind-limbs, ribs and vertebrae.<\/p>\n
Based on the bone microstructure, the paleontologists suggest that the specimen is an adult, but possibly not fully grown.<\/p>\n
Extrapolating from other megaraptoran remains, they estimate that Joaquinraptor casali may have been around 7 m in length and weighed more than 1,000 kg.<\/p>\n
Sedimentary evidence indicates that this dinosaur lived in a warm, humid floodplain environment.<\/p>\n
\u201cThe presence of a fossilized crocodile leg bone pressed against the lower jaws of Joaquinraptor casali gives hints about its feeding behavior and suggests it may have been an apex predator in the region,\u201d the researchers said.<\/p>\n
\u201cHowever, more research is needed to provide further insights into its behavior and ecological role.\u201d<\/p>\n
According to the scientists, Joaquinraptor casali and other megaraptorans survived as the dominant predators in this region of South America before going extinct at the end of the Cretaceous with other non-avian dinosaurs.<\/p>\n
\u201cSouth American megaraptorids appear to have attained larger body sizes (7\u2009m or greater in total body length) than their generally more ancient relatives from Australia (5-6\u2009m),\u201d they said.<\/p>\n
\u201cPatagonian megaraptorids may have continued to increase in size through the remainder of their evolutionary history \u2014 perhaps spurred at least in part by the extinction of carcharodontosaurids during the Turonian \u2014 with some latest Cretaceous forms potentially reaching body lengths of 9\u2009m or more.\u201d<\/p>\n
\u201cAmong other benefits, this may have allowed megaraptorids to occupy the apex predator niches in their respective habitats.\u201d<\/p>\n
\u201cMoreover, and as evidenced by the Maastrichtian (probably Late Maastrichtian) stratigraphic occurrence of Joaquinraptor casali, these theropods may well have survived to the Cretaceous-Paleogene boundary, only to ultimately perish alongside all other non-avian dinosaurs.\u201d<\/p>\n