In 1999, Rosendo Pascual and colleagues described a lower jaw of "Sudamerica", which had previously only been known from isolated teeth. This jaw fragment showed that "Sudamerica" had four molariform teeth on each side of the lower jaws, more than any multituberculate, and consequently they removed gondwanatheres from Multituberculata and regarded their affinities as uncertain. As a consequence, Kielan-Jaworowska and colleagues excluded Gondwanatheria from multituberculates, but identified the jaw fragment and a few upper premolars of "Ferugliotherium" as indeterminate multituberculates in a 2001 paper and a 2004 book. However, in 2009 Yamila Gurovich and Robin Beck identified these fossils as "Ferugliotherium" and argued in favor of a close relationship between gondwanatheres (including Ferugliotheriidae) and multituberculates.