Palaeontologists have described a dinosaur with heron-like behaviour

The new species was named Kank australis. Its remains were found in southern Patagonia, in the province of Santa Cruz, in rocks about 70 million years old. The finds include teeth, vertebrae and toe bones. Compared to nearby dinosaurs, researchers suggest the adult may have reached about 2.5 to 3 metres in length.

Details

Kank australis belonged to the Unenlagiidae, a group of small to medium-sized predatory theropods known mainly from finds from the Southern Hemisphere. Externally, these dinosaurs could resemble "raptors": they moved on two legs, had sharp teeth and an enlarged claw on the second toe.

But the new species is interesting not only that. According to the study, the cervical vertebrae of Kank australis had features related to muscle attachment and blood vessel protection. Such structures are important for complex neck movements in modern birds such as herons. Palaeontologists therefore suggest that the dinosaur could quickly extend and rotate its neck when hunting near water.

The environment fits this theory well, too. Kank australis lived in a landscape with meandering rivers, streams, seasonal ponds, aquatic plants, fish, insects and molluscs. Earlier studies of the rocks of the Chorrillo Formation also describe it as a fossil-rich Late Cretaceous continental environment with fluvial deposits and a variety of vertebrates.

So what we have before us is not necessarily a swift overland hunter that stalked prey across an open plain. This dinosaur may have often stayed close to the water and caught fish or other small animals in the coastal zone.

Why it matters

The find changes the usual image of "raptor-like" dinosaurs. We often picture them as terrestrial predators that ran after prey. But Kank australis shows that among such dinosaurs there may have been forms associated with aquatic environments.

It also adds detail to the picture of Late Cretaceous Patagonia. Several million years before the extinction of non-bird dinosaurs, wet ecosystems with rivers, ponds, plants, fish, amphibians, turtles, mammals and various predatory dinosaurs existed there.

The new species helps fill a gap in the history of unenlagiids. Previously, more finds of such dinosaurs were known from northern Patagonia. Kank australis shows that the group was distributed further south and may have occupied different ecological niches.

Background

Patagonia has long been known as one of the most important regions for the study of South American dinosaurs. In recent years, the Chorrillo Formation in Santa Cruz Province has yielded many finds, from dinosaurs and birds to mammals, fish, frogs, snakes, turtles, insects and plants. This is helping to reconstruct not individual animals, but entire ecosystems from the late Cretaceous period.

The name of the new dinosaur is also connected to the south. Kank refers to a myth of the Aonikenk people, a southern group of the Tewelche: it features a giant nandu, whose footprints seem to have formed the constellation of the Southern Cross in the sky. The species name australis means "southern" and indicates the place of discovery.

Source

Study: 'New Unenlagiid From The Chorrillo Formation (Late Cretaceous, Maastrichtian), SW Patagonia, Argentina', Journal of Vertebrate Paleontology, 2026.