Fossils of australosphenidans have been found from the Jurassic of Madagascar and Argentina, and Cretaceous of Australia and Argentina. Monotremes have also been considered a part of this group in some studies, but this is disputed.
The fossil record of australosphenidans spans the Jurassic and Cretaceous periods across various locations, including Madagascar, Argentina, and Australia.  Some researchers have included monotremes in their analysis of australosphenidan fossils, but this is not universally accepted.