What is "allotheria"

Allotheria (meaning "other beasts", from the Greek αλλός, allos-other and θήριον, therion-wild animal) is an extinct branch of successful Mesozoic mammals. The most important characteristic was the presence of lower molariform teeth equipped with two longitudinal rows of cusps. Allotheria includes Multituberculata, Gondwanatheria (which may be part of Multituberculata, as the sister group to Cimolodonta), and probably Haramiyida, though some studies show them to not even be mammals and differing from true allotheres significantly.

Allotheres also had a narrow pelvis, indicating that they gave birth to tiny helpless young like marsupials do. This is a feature of all non- placental mammals.