Triceratops relative ran on two legs

Previously hanged dinosaurs provide new insights into the evolution of four-legged gangs

The Auroraceratops is an early relative of the Triceratops, unlike this but he ran on two legs. © Robert Walters
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Still two-legged: Researchers have examined fossils of an early Triceratops relatives - with exciting results. Their analyzes show that the Auroraceratops was much smaller and had less imposing face jewelery than its famous descendant. Unlike the horned dinosaurs from the late Cretaceous, this dinosaur also seems to have been traveling on two instead of four legs.

In addition to the Tyrannosaurus the Triceratops today probably belongs to the most famous dinosaurs. He and other representatives of the horned dinosaurs are typically depicted as rhinoceros-like creatures with impressive horns and neck shields trudging through the primeval world on four powerful legs.

But in fact, not all Triceratops' relatives corresponded to this picture: some early representatives of the horned dinosaurs differed in some cases clearly from their famous descendants, as the example of the Auroraceratops rugosus shows. When this dinosaur was discovered in China fifteen years ago, only a single fossil skull bore testimony to its former existence - and the findings that paleontologists were able to gain about the anatomy and way of life of this dinosaur were scarce.

The Auroraceratops is one of the few early horned dinosaurs of which researchers know the entire skeleton. © Scott Hartman

Small and without big horns

Meanwhile, many more Auroraceratops bones were salvaged, including almost completely preserved animals. With fossil finds of more than 80 individuals, the Auroraceratops is one of the few early horned dinosaurs researchers know about the skeleton. "This Dino is the only representative of Neoceratopsia from the early Cretaceous with a fully preserved skeleton. Later on, the Triceratops also emerged from this group, "explain Hailu You of the Chinese Academy of Sciences in Beijing and his colleagues.

Thanks to the many new discoveries, scientists now have a new look at this dinosaur that lived on our planet 115 million years ago. Their analyzes show that the Auroraceratops, in contrast to his famous relative, was rather small. Accordingly, he was only about 1.25 meters long, 44 inches high and 15 pounds. The characteristic features of the Auroraceratops included a short neck shield and the beak-shaped mouth typical of hearing dinosaurs. However, the big horns and other Triceratops features were still missing from this Dino. display

From two to four legs

The Auroraceratops also differed from Triceratops in another point: he obviously did not run on four but on two legs. According to You and his team, the bulging thigh bones and the long, thin claws on the legs indicate that. This bipartishness makes the dinosaur especially valuable for the researchers.

For sometime in the Cretaceous period, two-legged dinosaurs produced those four-legged friends that can be found today in every children's book about dinosaurs. "The Auroraceratops now provides us with clues as to how the last two-legged Ceratopsia may have looked and what changes accompanied the transition from bi- to quadrupleture in these dinosaurs, " concludes co-author Eric Morschhauser the Indiana University of Pennsylvania. (Journal of Vertebrate Paleontology, 2019, doi: 10.1080 / 02724634.2017.1396995)

Source: University of Pennsylvania

- Daniel Albat