“Toucan” of the dinosaur era discovered

Artist’s impression of the primeval bird with the unusual beak. (Image: Mark Witton)

A study shows that even between the dinosaurs, many different species of birds whizzed through the air: Researchers report on a new representative of the extinct bird group of the enantiornithes. The animal the size of a crow still had a tooth, but the shape of the beak already looked surprisingly modern: it was curved like a toucan, but formed from different structures than modern birds. It is thus an example of parallel evolution, say the paleontologists.

The bird world we see today has its origins in the age of the dinosaurs: During the Jurassic and Cretaceous ages, two-legged dinosaurs became the ancestors of the winged aerialists. Initially, two lines emerged: the ancestors of today’s birds and the so-called enantiornithes, which were still the dominant form in the Cretaceous period. The representatives of this group of birds had special wing characteristics and snout-like beaks with teeth. Otherwise, however, they were very similar to today’s birds and were probably also skilled fliers. Fossil finds show that the enantiornithes were widespread in the Cretaceous world and had already developed a considerable range of species. In contrast to the ancestors of today’s birds, however, the enantiornithes shared the fate of the dinosaurs: all species died out as a result of the asteroid impact around 66 million years ago.

An amazing brain is emerging

The researchers led by Patrick O’Connor from Ohio University in Athens now report on a particularly interesting representative of this primeval group of birds. The findings are based on the study of a fossil skull that was estimated to be 68 million years old. It comes from a site on the island of Madagascar. The remains of the approximately nine centimeter long head are so filigree that the palaeontologists could not dissect them from the rock without destroying them. That is why they used modern analysis technology: The find was x-rayed using high-resolution micro-computer tomography. The researchers were able to virtually free the fine structures from the rock and ultimately develop a three-dimensional model.

So it became apparent: It was the skull including the upper beak of a previously unknown representative of the enantiornithes. The researchers named the roughly crow-sized animal Falcatakely forsterae. As the studies showed, this primeval bird had a surprising characteristic: It had a strikingly curved beak – similar to today’s toucans. “As soon as the contours began to emerge, we knew straight away that we had something special ahead of us,” says O’Connor. “Mesozoic birds with such tall, long structures were previously completely unknown,” emphasizes the paleontologist. The tooth structures typical of the enantiornithes, however, were hardly pronounced in this species: The researchers only found one tooth at the tip of the beak structure – but there may have been several once.

Example of parallel evolution

Interestingly, as he and his colleagues report, the toucan-like appearance was not based on the face and beak structures found in today’s birds. As they explain, the upper beak in Toucan and Co mainly emerges from a single enlarged bone, the so-called premaxilla. In contrast, the primeval birds from the time of the dinosaurs still had structures that consisted of a small premaxilla and a large portion of the upper jawbone (maxilla). Surprisingly, the researchers found this snout-like structure also in Falcatakely. Nevertheless, its shape resembled the high, long upper beak of modern birds.

“It’s the underlying skeletal structure of the face that makes Falcatakely so special,” says O’Connor. “Obviously there are different ways of organizing these structures that lead to similar end results – in this case a similar head and beak shape,” says the paleontologist. As he and his colleagues explain, it is therefore an example of the phenomenon of parallel or convergent evolution. This leads to the development of outwardly similar characteristics in animal species that are only distantly related to one another. These properties arise in similar habitats and mostly serve comparable purposes. One example is the body shapes of marine mammals, which are similar to those of fish.

“It turns out that some modern birds like toucans and hornbills have developed very similar sickle-shaped beaks again many millions of years after Falcatakely. The amazing thing is that these traits emerged in parallel, because these animals were only very distantly related, ”says co-author Ryan Felice of University College London. The exact purpose of Falcatakely’s sickle-shaped beak, however, will probably remain a secret of Cretaceous Madagascar.

Source: Ohio University, article: Nature, doi: 10.1038 / s41586-020-2945-x

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