Description and Classification

Thanatosdrakon was one of the largest flying animals ever discovered, with an estimated wingspan of around 9 meters (about 30 feet) for the larger individual found. This is comparable to the size of a small airplane. Unlike birds, pterosaurs had wings made of a leathery membrane stretched between a very long fourth finger and their bodies. Thanatosdrakon possessed a long neck and a large, elongated, toothless beak, characteristic of its family, the Azhdarchidae. This family includes other giant pterosaurs like Quetzalcoatlus from North America and Hatzegopteryx from Europe. Azhdarchids are known for their impressive size and adaptations for a terrestrial lifestyle when not flying. The fossils of Thanatosdrakon are remarkably well-preserved for such a large pterosaur, including bones from the spine, shoulders, hips, and limbs, offering valuable insights into their anatomy.

Within the Azhdarchidae, Thanatosdrakon is considered a distinct genus due to several unique features in its bones. It represents one of the oldest and most complete giant azhdarchids found in South America, showing that these enormous creatures were already thriving on the continent during the Coniacian-Santonian ages of the Late Cretaceous.

Distinguishing Features

Thanatosdrakon can be identified by several unique characteristics, particularly in its skeletal structure. Some of these include:

• An exceptionally large wingspan, reaching up to 9 meters (30 feet), making it one of the largest pterosaurs from South America.
• Specific features in its vertebrae, such as the structure of its notarium (fused backbones that supported the shoulder girdle) which differs from other azhdarchids.
• Relatively robust bones compared to some other pterosaurs, suggesting a strong build.
• The presence of two individuals of different sizes found together, which is rare for giant pterosaurs.

These features, among others identified by paleontologists, help distinguish Thanatosdrakon from related pterosaurs like Aerotitan, another azhdarchid found in Argentina, and the more famous Quetzalcoatlus.

Paleoenvironment and Diet

Thanatosdrakon lived in what is now the Mendoza Province of Argentina. During the Late Cretaceous, this area, represented by the Plottier Formation, was a floodplain environment with rivers and seasonal rainfall. It was a landscape shared with various dinosaurs, including giant titanosaur sauropods and predatory abelisaurid theropods. Trees and other vegetation would have grown along the riverbanks, providing diverse habitats.

Like other azhdarchids, Thanatosdrakon is thought to have been a terrestrial stalker. This means that despite its ability to fly vast distances, it likely spent a good amount of time on the ground hunting. With its long neck and large beak, it could have preyed on a variety of small to medium-sized animals, including young dinosaurs, lizards, fish if near water, and other small vertebrates. Its large size would have made it a formidable predator in its ecosystem. It may have walked on all fours, using its folded wings as front limbs, similar to how a giraffe might walk, but with wings instead of front legs.

Significance and Ongoing Research

The discovery of Thanatosdrakon is highly significant for several reasons. It is one of the largest pterosaurs ever found and provides some of the most complete fossil material for a giant azhdarchid from South America. This allows scientists to better understand the anatomy and evolution of these enormous flying reptiles. The excellent preservation helps compare its features with other azhdarchids worldwide, like Quetzalcoatlus and Arambourgiania, and understand how gigantism evolved in this group.

The fact that two individuals were found together is also important. While it doesn’t definitively prove they lived in groups, it offers a rare opportunity to study potential variations between individuals or perhaps social behavior. Ongoing research continues to analyze the fossils of Thanatosdrakon to learn more about its flight capabilities, how it moved on land, and its exact role in the Late Cretaceous ecosystem. Its discovery has added another spectacular creature to the list of ancient life from Patagonia, a region famous for its rich fossil record, and reinforces the idea that giant pterosaurs were diverse and widespread during the final era of the dinosaurs.