Scientists have a found a new megaraptor fossil in Patagonia, with a crocodile leg caught in its teeth. Which means that megaraptorans may have been the apex predators of their time (70 million years ago) and space (Argentinian Patagonia).
Megaraptors a relatively not-well-understood branch of theropods, having massive claws in their forelimbs. Generally above 14 feet (4.2m) in length, megaraptors could reach 42 feet (12.8m). Joaquinraptor casali, described in a new study published last month, was likely 23 feet (7m) in length.
Size comparison. Wikimedia Commons
Apex predator of its time
What is most astounding about this new species is the evidence of what its food was. Paleontologists found Joaquinraptor with a fossilised leg of a crocodiloform in its mouth. This could indicate its position in the cretaceous food chain. “Megaraptorids appear to have been the apex predators in central and southern Patagonian palaeoecosystems approaching the end of the Cretaceous“, wrote the researchers.
Putative evidence of dietary preference and/or prey capture in Joaquinraptor casali a Dentaries of Joaquinraptor (UNPSJB-PV 1112) and an associated crocodyliform right humerus (UNPSJB-PV 1113) in the position in which they were recovered prior to their mechanical separation in the laboratory (right dentary in lateral view, left dentary in medial view, humerus in posterior view [proximal end only]). b Detail of a showing a portion of the crocodyliform humeral shaft (UNPSJB-PV 1113) in contact with the right dentary tooth crowns of Joaquinraptor (UNPSJB-PV 1112). c Crocodyliform right humerus (UNPSJB-PV 1113) in anterior view. Abbreviations: d dentary, mg Meckelian groove, pdg paradental groove. Image Credit: Lucio M. Ibiricu et al
“Interestingly, this bone was situated between the closely associated left and right dentaries of the Joaquinraptor holotype, with the apices of several tooth crowns of the megaraptorid in direct contact with the humeral shaft, which also shows potential tooth marks. As such, this discovery may constitute direct evidence regarding prey selection within Megaraptoridae“
A well-preserved specimen will improve understanding of megaraptorans
Paleontologists have found Megaraptorans in Cretaceous deposits of Asia, Australia, and especially South America. However, we still don’t understand a lot about them, mainly because of the fragmentary nature of most fossils of these theropods. Joaquinraptor is among the most completely represented and latest-surviving megaraptorans.
“Its stratigraphic occurrence indicates that these dinosaurs likely persisted to the Cretaceous/Palaeogene boundary“, the scientists wrote. J. casali lived between 70 to 66 million years ago. It likely went extinct at the same time as the other non-avian dinosaurs during the Cretaceous extinction event.