Ferugliotherium is a
genus of fossil
mammals in the family
Ferugliotheriidae from the
Campanian and/or
Maastrichtian period (
Late Cretaceous; around 70 million years ago) of Argentina. It contains a single species,
Ferugliotherium windhauseni, which was first described in 1986. Although originally interpreted on the basis of a single
brachydont (low-
crowned)
molar as a member of
Multituberculata, an extinct group of small, rodent-like mammals, it was recognized as related to the
hypsodont (high-crowned)
Sudamericidae following the discovery of additional material in the early 1990s. After a jaw of the sudamericid
Sudamerica was described in 1999, these animals (collectively known as
Gondwanatheria) were no longer considered to be multituberculates and a few fossils that were previously considered to be
Ferugliotherium were assigned to unspecified multituberculates instead. Since 2005, a relationship between gondwanatheres and multituberculates has again received support. A closely related animal,
Trapalcotherium, was described in 2009 on the basis of a single tooth.
About twenty teeth and a jaw fragment have been referred to
Ferugliotherium, but the assignment of many of these is controversial or has been superseded. The upper and lower
incisors are long and rodent-like and have
enamel on only one side of the crown. A fragment of the lower jaw shows that the
tooth socket of the lower incisor was very long, extending below the fourth
premolar (p4). The p4 is preserved in this fragment. It is blade-shaped and resembles multituberculate p4s. However, the determination of this fossil as
Ferugliotherium is in question. The identity of a few additional isolated premolars assigned to
Ferugliotherium, some resembling multituberculates, is also uncertain. The first lower molariform (molar-like tooth; mf1) is known from four examples, of which two were originally identified as upper molars of a different species (
Vucetichia gracilis), which is now considered a
synonym of
Ferugliotherium. They bear two longitudinal rows of three or four
cusps and transverse crests and furrows. A single example each of the second lower (mf2) and first upper molariform (MF1) show that these teeth also had longitudinal cusp rows and transverse furrows and crests, but the mf2 had only two or perhaps three cusps per row and the MF1 had three longitudinal rows. (
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