Australosphenida

The Australosphenida are a clade of mammals, containing mammals with tribosphenic molars, known from the Jurassic to Mid-Cretaceous of Gondwana. In tribosphenic teeth, the lower molar is divided into two regions: the three-cusped trigonid, or shearing end, and the talonid, or crushing heel. Although they have often been suggested to have acquired tribosphenic molars independently from those of Tribosphenida, this has been disputed. 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 its original definition and in many subsequent studies, but its relationship with other members has been disputed by some scholars.

== Taxonomy == This grouping includes the following taxa: †Henosferidae, including the genera Ambondro, Asfaltomylos, and Henosferus from the Jurassic of Argentina and Madagascar. †Ausktribosphenidae known from the Early Cretaceous of Australia †Bishopidae including Bishops from the Lower Cretaceous of Australia and an unnamed genus from the Mid-Cretaceous of Argentina (the latter of which was originally attributed to Ausktribosphenidae). †?Vincelestes, sometimes recovered as an australosphenidan (when not inversely considered a cladotherian). †?Tendagurutherium, recovered as an australosphenidan in one study. ?Monotremata, one of the three major living groups of mammals, known from the Early Cretaceous to present of Australia-New Guinea and the Late Cretaceous-Paleocene of southern South America.