[4] They are generally considered to be closely related to the multituberculates and likely the euharamiyidians, well known from the Northern Hemisphere, with which they form the clade Allotheria.

[5] For several decades the affinities of the group were not clear, being first interpreted as early xenarthrans, or "toothless" mammals similar to the modern anteater.

The family Ferugliotheriidae was named by José Bonaparte in 1986, and includes one genus, Ferugliotherium, and possibly a few other forms like Trapalcotherium from the Late Cretaceous of South America.

Vintana possesses bizarre jugal flanges similar to those of xenarthrans like ground sloths, though they had a palinal (front-to-back) chewing method as in most allotheres and unlike almost any therian.

Aside from these derived features, the Malagasy mammal has a mosaic pectoral girdle morphology: the procoracoid is lost, the coracoid is extremely well developed (into an enlarged process that contributes to half of the glenoid fossa), the interclavicle is small, and the sternoclavicular joint appears mobile.