Australia: Triassic’s largest predatory dinosaur missing – 220 million-year-old footprints from a plant

Misunderstood: The largest and oldest predatory dinosaur footprints in Australia actually came from very small, prehistoric reptiles, a new analysis of prints reveals. Thus, the 220-million-year-old, three-legged footprint does not match that of a carnivore, but rather features of a four-legged plant. But at least: these prints are the earliest evidence of this Sauropodomorpa in Australia.

Not only did the dinosaurs and their ancestors leave their fossil bones – the footprints also bear witness to their earlier existence. Such dinosaur footprints not only reveal what species once lived there, but they also provide valuable insights into the behavior and way of life of most prehistoric lizards. So prove it Printed in Alaska, Dinosaurs occurred beyond the Arctic Circle and moved between continents. There are traces even in the UK Details of scales and skin Is protected. And prints in German Manchehegan May come from mother and baby.

Embedded in the ceiling of the coal mine

In Australia, footprints are the only evidence of the existence of dinosaurs in the Triassic. There are no dinosaur fossils in this era that ended 200 million years ago. The problem, however, is that the Triassic dinosaur prints contain some footprints discovered by miners at two coal mines in Queensland 50 years ago. Experts drew those traces, but only one plaster cast is still preserved today. The tracks have been destroyed for a long time.

One of these traces contains three seals that came to light on the roof of a gallery in the Rhonda mine in 1964, located 200 meters below the ground. Anthony Romilio, lead author of the University of Queensland in Brisbane, said: “It would have been a different scene for miners in the 1960s to see these large, bird-like tracks being dragged to the ceiling.

Described as a theropod seal

Because of their three-legged shape and good 40 cm size, the axles from Rhonda were previously considered the legacy of a large, two-legged predatory dinosaur. “It has been believed for many years that these tracks are at least two meters long and were created by a theropod belonging to the Eubrontes group,” says Romilio. “It was a sensation because no other carnivorous dinosaur of this size from the Triassic is known anywhere in the world.”

The problem, however, is that since the original traces were destroyed during the coal mining, most ancient researchers had only maps and blurred photographs to evaluate the prints. Therefore, interpretations of size and key features may differ significantly in some cases. To further clarify, Romilio and his team meticulously looked at drawings, photographs, and the remaining plaster casts of one of these impressions.

Misinterpretation of shape and size

New analysis reveals: Previous researchers miscalculated nails in addition to foot length. If you remove this, the axes will only be 34 cm long and 32 cm wide. With the distance between the individual tracks documented in the historical records, this suggests that the originator of these tracks had only 1.36 meters of legs instead of the two meters previously considered.

In addition, the length-width ratio changes significantly as the length of the axes decreases – this is only 1.06, according to Romilio and his colleagues. However, the shape of the axes also differs significantly from the tracks of the Euphrates, with a length-to-width ratio of 1.4 to 1.5. Further discrepancies are the internal rotation of the footprints and the details of the foot axes, which, according to ancient researchers, do not match the Euphrodis.

Plant species instead of predatory dinosaurs

But who left these traces? According to Romilio and his team, the prints are not from a carnivorous tropot, but from a plant species, the Triassic dinosaur. “The more we looked at the tracks and toe records, the less they resembled the traces of predatory dinosaurs,” says Hendrik Klein, co-author of the Sauerwealth Antiquities Museum in Newmark.

Researchers estimate that there are traces of a representative that is 1.40 meters high and six meters long. Sauropodomorpa Were made. These Triassic plant species are the forerunners of the later giant long-necked dinosaurs Saropods. As Romilio and his colleagues explain, the axes of such early sauropod predecessors known as the Evazoum are similarly twisted and fit well in shape.

Early evidence of Saropodomorpa in Australia

If this is confirmed, it will have two antiquated consequences: On the one hand, whether there were any carcass throats in the Triassic in Australia has been completely reopened. On the other hand, Rhonda’s footprints are the oldest evidence of Saropodomorpa in Australia. “This is the earliest evidence of this type of dinosaur in Australia,” says Romilio. “The next oldest fossils of four-legged sauropods are about 50 million years younger.” (Historical Biology, 2021; doi: 10.1080 / 08912963.2021.1984447)

Quelle: Taylor & Francis Group

October 26, 2021

– Nadja Podbregar