In the 2000s, additional members of Ferugliotheriidae were described. In 2004, Francisco Goin and colleagues described a single enigmatic tooth from the Paleogene of Peru, LACM 149371; their best estimate was that it represented a member of Ferugliotheriidae. On the basis of a single p4, Kielan-Jaworowska and colleagues named "Argentodites coloniensis", from the Late Cretaceous La Colonia Formation of Argentina, in 2007 as a multituberculate, possibly referable to the suborder Cimolodonta. Gurovich and Beck argued, however, that the p4 of "Argentodites" did not differ materially from that in the jaw they allocated to "Ferugliotherium", and that "Argentodites" was based on a specimen of either "Ferugliotherium" or a closely related animal. Guillermo Rougier and colleagues described mammals from the Allen Formation, a third Argentinean formation of similar age, in 2009, including a new ferugliotheriid, "Trapalcotherium matuastensis". They also regarded "Argentodites" as a likely relative of "Ferugliotherium" and suggested that Ferugliotheriidae are either multituberculates or closely related to them.