An article published in the journal “Science of Nature” reports the identification of a new species of dinosaur with characteristics similar to birds that lived about 90 million years ago, in the Cretaceous period, in today’s Patagonia, Argentina. A team of researchers led by Matias Motta named it Overoraptor chimentoi, a name that reminds more of predatory dinosaurs than birds. In fact, some of its characteristics are typical of that type of dinosaur, with legs suitable for running and a claw similar to that of Velociraptor on its second toe. Instead, its arms have characteristics much closer to bird wings, and this suggests that it’s one of the species closest to birds among the various known raptors.
In recent decades, paleontologists have discovered various species attributed to the group of paravians, theropod dinosaurs that include birds as well as some dinosaur families that became extinct at the end of the Cretaceous period. Many species were discovered in China, but paravians were also widespread in other continents such as the one discovered in the Huincul Formation in the Rio Negro province in Patagonia, Argentina. The discovery of the partial skeleton of a Paravian was followed by that of fragments of another specimen attributed to the same species, which was named Overoraptor chimentoi by the team led by Matias Motta of CONICET (Consejo Nacional de Investigaciones CientÃficas y Técnicas) and the Museum of Argentine Natural Sciences “Bernardino Rivadavia”.
The top image (Cortesia Motta et al, doi: 10.1007/s00114-020-01682-1. All rights reserved) shows a silhouette of an Overoraptor chimentoi which indicates the bones available together with them.
This dinosaur was small, with a length of approximately 130 centimeters. Like many paravians that weren’t birds, this species exhibits mixed characteristics that include various adaptations to flight together with others typical of dinosaurs. Overoraptor chimentoi had wings similar to those of modern birds but its legs were similar to those of Velociraptor, suitable for running and with a lethal claw on its second toe.
The different species of dinosaurs related to birds had wings with different levels of functionality. In the Overoraptor chimentoi’s case, the examination of the arm bones indicates that it was related to birds more closely than most known raptors. However, this dinosaur was a runner, and maybe it used its wings for a better balance as certain birds such as ostriches do today.
According to the researchers, Overoraptor chimentoi’s anatomical characteristics indicate that it was closely related to Rahona ostromi, another paravian that lived later, about 70 million years ago, in today’s Madagascar. This species was discovered in 1995 and also had legs similar to Velociraptor’s and wings similar to birds’.
The paravians that lived in the ancient continent of Gondwana are little known because of fossil scarcity, a typical problem in the field of paleontology. This means that a discovery such as that of Overoraptor chimentoi is important in the reconstruction of the history of this group of dinosaurs and the evolution of wings with the different adaptations discovered in the various species.
