Allotheria

Allotheria ("other beasts", from the Greek allos-other and therion-wild animal) was a branch of successful mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudinal rows of cusps.

Interpretations
When he first identified Allotheria in 1880, Othniel Marsh regarded this group as an order within Marsupialia. But in 1997, McKenna and Bell classified Allothera as an infraclass.