The pterosaurs reached a wingspan of up to twelve meters at the height of their dominance over the airspace. But the flying lizards, the first vertebrates that flew by their own power, also started small at one time. This is shown by the fossils of the 230-million-year-old lizard Scleromochlus taylori, discovered as early as 1907, which a team led by Davide Foffa from the National Museums of Scotland in Edinburgh now clearly identified as close relatives of the pterosaurs. As the team reports in "Nature", the finding supports the thesis that pterosaurs originated from ground-living lizards that at least partly ran on two legs.
The evolutionary origin of the Pterosaurs is still mysterious because their building is so extremely different from anything that is otherwise known from reptiles. And the anatomy of Scleromochlus Taylori also gives up puzzles - not least because the millions of years have strongly deformed the rare fossils and they often only know their impressions in the rock. Some of them even considered a crocodile relative, and there was also a dispute whether he ran, crawled like modern lizards or even hopping like a frog.
To answer these questions, Foffa's team scanned a fossil of the lizard in a high-precision computer tomograph. On this basis, it reconstructed the entire skeleton and, above all, its probable posture. The result shows that it is indeed a close relative of the pterosaurs. For example, its skull is unusually long, a trend that took on extreme proportions among flying lizards. In addition, his limbs indicate that he was not a pure four-legged friend. Perhaps the pterosaurs, like modern birds, originated from fast two-legged runners that could use the forelimbs to flutter.
