Its joint allowed it to flex in a different plane than the other phalanges in order to control the cruropatagium, as seen preserved in the specimen of Sordes pilosus PIN 2585.3.

The specific name, zambellii, honours Rocco Zambelli, the curator of the Bergamo natural history museum.

[5] It also had single cusped teeth that lacked the specialized heterodonty present in the other Italian Triassic pterosaur genus, Eudimorphodon.

[5] All these factors converge to hint that Peteinosaurus belongs to a group that possibly represents the most basal known pterosaurs: the Dimorphodontidae, to which it was assigned in 1988 by Robert L.

A 2010 cladistic analysis by Brian Andres and colleagues placed Peteinosaurus in Lonchognatha which includes Eudimorphodon and Austriadactylus as more basal.

[10] A study published in 2020 found support for a sister-taxon relationship between Peteinosaurus and Macronychoptera, which together form the clade Zambellisauria.