Palaeontology: New species of ankylosaur discovered in Chile

 
A new species of Ankylosaurus, found in the subantarctic region of Chile, provides new clues about the origin and early evolution of armored dinosaurs.A paper reporting this finding will be published in Nature.The findings reveal that Stegouros elengassen has evolved a large tail as a weapon, a feature not found in other dinosaurs.

Ankylosauria ankylosauria, found in the northern Laurasia continent, which was once part of the Pangea supercontinent, is a diverse dinosaur species that has been studied in detail.On the other hand, it is thought that the Ankylosaurus in the southern Gondwana continent contains the oldest Ankylosaurus, but its fossils have hardly been found and have not been elucidated. ..

This time, Alexander Vargas and colleagues found a well-preserved, almost complete skeletal fossil found in Magalanes, the southernmost tip of Chile, in a small size of about 7170 meters in length in the Late Cretaceous (about 7490 million to 2 million years ago). It is reported to be the skeleton of Ankylosaurus. Vargas et al. Revealed that this was a new species of Ankylosaurus and named it Stegouros elengassen. Stegouros has unique skull features similar to other ankylosaurus, but most of the other skeletons are primitive and are thought to contain Stegouros-like features.Stegouros also has a large tail that can be used as a weapon, and a phyllodes structure fused with seven pairs of flat bone deposits is formed throughout the distal part of this tail.In this respect, it differs from the pair of tail spikes and tail weights found in other armored dinosaurs.Also, when Vargas et al. Performed a phylogenetic analysis (corresponding to creating a phylogenetic tree of Ankylosaurus), Stegouros is a type of Ankylosaurus, especially Kunbarrasaurus in Australia and Antarctopelta in Antarctica. It turned out to be closely related to Antarctopelta.

Based on the above findings, Vargas et al., It is possible that another branch existed in the ankylosaurus phylogenetic tree on both continents after the Pangea supercontinent was completely divided into Laurasia and Gondwana in the Late Jurassic. I conclude that there is. Vargas et al. Reiterate that this hypothesis, along with other possibilities raised by Stegouros' discovery, remains largely unclear regarding the evolution of armored dinosaurs, especially the evolution of armored dinosaurs on the Gondwana continent. Says.

 
* This article is reprinted from "Nature Japan Featured Highlights".
Reprinted from: "Paleontology: A new species of Ankylosaurus found in Chile'