Meet Peteinosaurus, the tiny, winged lizard that challenges our understanding of early flight

Nature · Published 3 October 2026 Swipe more like this →

In short: Living 218 to 215 million years ago, Peteinosaurus was among the earliest and smallest pterosaurs ever discovered. With a wingspan as small as 60 centimeters, this insect-eating creature possessed unique anatomical features that continue to spark intense debate among paleontologists regarding its exact place in the evolutionary tree of flight.

Discovered near Cene, Italy, and formally described by Rupert Wild in 1978, Peteinosaurus zambellii remains a subject of scientific scrutiny. The genus is known from three fossil specimens, all of which represent subadults. Notably, none of these fossils include a preserved skull, leaving researchers to reconstruct its appearance based on fragmentary remains. The holotype, cataloged as MCSNB 2886, is disarticulated, while other specimens like MCSNB 3359 lack definitive diagnostic features, leading some to question if they truly belong to the same species.

The anatomy of Peteinosaurus offers a window into the evolution of early pterosaurs. It featured strong yet lightweight bones and a specialized fifth toe, which likely helped control the cruropatagium—the membrane between its hind limbs. Unlike later pterosaurs, whose wingspans were at least three times the length of their hindlimbs, Peteinosaurus had proportionally smaller wings, measuring only twice the length of its hindlimbs. Its teeth were trimorphodontic, featuring three types of conical shapes, which supports the theory that it was an insectivore.

Classifying Peteinosaurus has proven difficult, with various researchers proposing conflicting evolutionary placements. While Robert L. Carroll assigned it to the family Dimorphodontidae in 1988, later cladistic analyses have challenged this connection. Some experts, such as Fabio Marco Dalla Vecchia, have suggested it might be a senior synonym for Preondactylus, while others, like Brian Andres, placed it within the Lonchognatha group in 2010. More recently, a 2020 study proposed a sister-taxon relationship with Macronychoptera, forming a clade known as Zambellisauria. Despite these shifting theories, Peteinosaurus remains a vital, if enigmatic, piece of the puzzle in understanding how the first vertebrates took to the skies.

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