Ferugliotherium - Range and Ecology

Range and Ecology

Remains of Ferugliotherium come from two formations in the Late Cretaceous of southern Argentina, the Los Alamitos and La Colonia Formations. These and the Allen Formation (which has yielded Trapalcotherium) are all dated to the Campanian (84–71 million years ago) and/or Maastrichtian (71–66 million years ago), the penultimate and ultimate stages of the Cretaceous. The La Colonia Formation may be somewhat younger than the other two, while the Los Alamitos Formation has been considered Campanian, and can be dated to the Campanian or Maastrichtian on the basis of palynology. The Allen Formation is likely Maastrichtian, but not latest Maastrichtian.

The Los Alamitos Formation is located in southeastern Río Negro Province, in the vicinity of the town of Cona Niyeu and was probably deposited in a marshy environment. In 1983, it yielded the first Mesozoic mammal to be found in Argentina, Mesungulatum houssayi, and since then, the mammalian fauna has expanded to 14 species. Most of those belong to the archaic mammalian group Dryolestoidea, but the fauna also includes the gondwanatheres Ferugliotherium and Gondwanatherium, and the unusual possible triconodont Austrotriconodon. The dryolestoids Mesungulum houssayi and Groebertherium novasi and the two gondwanatheres are the most common mammals. Other fossils found in the Los Alamitos Formation include fish, frogs, turtles, madtsoiid snakes, dinosaurs such as Secernosaurus, gastropods, and other invertebrates.

The La Colonia Formation outcrops in north-central Chubut Province, and the mammalian fossils come from the Mirasol Chico valley. The formation includes fluvial (river), deep-sea, and near-shore deposits, and the mammalian fauna probably comes from an estuary, tidal flat, or coastal plain. The La Colonia Formation also contains dryolestoids, such as Coloniatherium and Reigitherium, as well as a ferugliotheriid and the putative multituberculate Argentodites. In addition, the La Colonia Formation has yielded fossils of a wide array of other animals, including crocodiles, plesiosaurs, lungfish (Ceratodus), and dinosaurs (including Carnotaurus).

The high-crowned sudamericids were probably herbivores, but the lower-crowned Ferugliotherium was more probably an insectivore or omnivore, like similar multituberculates such as Mesodma, which is thought to have eaten insects, other arthropods, seeds, and/or nuts. It may have used its incisors for gnawing or slicing, and the blade-like p4 may also have been used for slicing hard plant parts, such as seeds. The wear patterns on Ferugliotherium teeth independently suggest that the animal may have eaten some plant material.