Palaeontology: New classification for an ancient Scottish reptile

Reassessment of an enigmatic fossil reptile from the Triassic of Scotland (around 230 million years ago) reveals that it was a close cousin of the flying pterosaurs. The study, published in Nature this week, sheds light on on one of the closest relatives of the first vertebrates to fly.

Pterosaurs were the first vertebrates to evolve powered flight, but their evolutionary history is uncertain. Scleromochlus taylori was a small (less than 20 cm long) reptile with a large head, short neck, slender body, spindly legs and a long tail. Discovered over a century ago in the Upper Triassic Lossiemouth Sandstone Formation of Scotland, its poorly preserved remains saw scientists place it in a number of different groups. Here, Davide Foffa and colleagues use micro-computed tomographic scans to provide a highly detailed reconstruction of the reptile. New anatomical details are revealed, suggesting that Scleromochlus belonged to Pterosauromorpha — the clade that includes pterosaurs and a group of small reptiles called lagerpetids. Scleromochlus is more similar to lagerpetids than to pterosaurs, making it one of the earliest branching lagerpetids. It seems the first flying reptiles may have evolved from creatures similar to this tiny, toe-standing, probably bipedal terrestrial runner.