Previously, in 1821, Gray named the superfamily Didelphoidea to house the families Alphadontidae, Pediomyidae, Peradectidae, and Stagodontidae, which unites Didelphodon with many other genera.

[2] Gurlin Tsav skull Borhyaenidae Mayulestes Jaskhadelphys Andinodelphys Pucadelphys Asiatherium Iugomortiferum Kokopellia Aenigmadelphys Anchistodelphys Glasbius Pediomys Pariadens Eodelphis Didelphodon Turgidodon Alphadon Albertatherium Marsupialia Although it has been argued on the basis of the shape of referred tarsal bones that Didelphodon and other stagodontids were semiaquatic due to having flexible feet, these traits may in fact be evidence of increased rigidity in the foot.

[1][3] Nevertheless, a recently-found and as-of-yet undescribed specimen, located just 40 m (130 ft) away from a Triceratops in a riverbed, suggests that Didelphodon may have possessed an otter-like body with a tasmanian devil-like skull.

A study that is being prepared by Kraig Derstler, Greg Wilson, Robert Bakker, Ray Vodden and Mike Triebold will describe this new specimen, housed in the Rocky Mountain Dinosaur Resource Center.

[8] Given that all insectivorous and carnivorous mammal groups suffered heavy losses during the mid-Cretaceous, it seems likely these metatherians simply occupied niches left after the extinction of most eutriconodonts.