Zupaytheriumrex

From Zupay (Mapudungun: "demon" or "evil spirit") + therium (Greek: "beast"). Species epithet rex (Latin: "king").

After a thorough search of major biological databases (including PubMed, Web of Science, Google Scholar, and the International Code of Zoological Nomenclature),

We thank the Museo Carmen Funes for access to collections. zupaytheriumrex

Below is a written in the format of a formal paleontological journal, using the name Zupaytherium rex as a hypothetical new genus and species. This is for illustrative/educational purposes to show how a real paper would be structured. Hypothetical Journal Article Title: A new large-bodied eutriconodontan mammal from the Late Cretaceous of Patagonia: Implications for predatory niche occupation in Gondwanan ecosystems

We describe a new genus and species of large-bodied eutriconodontan mammal, Zupaytherium rex gen. et sp. nov., from the Late Cretaceous (Campanian–Maastrichtian) Allen Formation of Río Negro Province, Argentina. The holotype consists of a partial skull, dentary, and associated postcranial remains (MPCN-PV-9876). Zupaytherium is characterized by robust, sectorial cheek teeth with three main cusps in a straight line, a deep masseteric fossa, and an estimated body mass of 45–60 kg, making it one of the largest Mesozoic mammals known from South America. Phylogenetic analysis places it within the eutriconodontan family Gobiconodontidae. The discovery extends the temporal and geographic range of large predatory mammals into the uppermost Cretaceous of Gondwana and suggests that mammals competed directly with small theropod dinosaurs for apex mesopredator roles. From Zupay (Mapudungun: "demon" or "evil spirit") +

Mammalia Linnaeus, 1758 Eutriconodonta Kermack, Mussett & Rigney, 1973 Gobiconodontidae Chow & Rich, 1984 Zupaytherium gen. nov.

The dentary is robust, with a deep masseteric fossa extending below m2. The lower molars are highly sectorial, with cusp a (protoconid) slightly taller than cusp b (paraconid) and cusp c (metaconid). Wear facets indicate carnivorous function with a vertical shearing motion. Estimated femoral length suggests a body mass of ~52 kg using allometric equations for extant carnivorans. Below is a written in the format of

Mesozoic mammals have traditionally been viewed as small, nocturnal insectivores. Recent discoveries from Laurasia ( Repenomamus , Gobiconodon ) have challenged this paradigm, revealing carnivorous mammals exceeding 10 kg. However, no large-bodied Mesozoic mammals have been described from South America. Here we report Zupaytherium rex , a new predator from the latest Cretaceous of Patagonia.

MPCN-PV-9876, an associated partial skeleton including a right dentary with m1–m3, a fragmentary maxilla with M2–M4, axis vertebra, and partial right femur.

Zupaytherium rex demonstrates that large predatory mammals evolved independently in Gondwana near the end of the Cretaceous. The presence of a 50+ kg mammal in the Allen Formation suggests that terrestrial food webs were more complex than previously recognized, with mammals occupying the 30–60 kg predator niche typically filled by small abelisauroid theropods in other Gondwanan faunas.

M. L. Chimento¹, F. A. Agnolin¹², and N. R. Chimento³ ¹Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia," Buenos Aires, Argentina ²Fundación de Historia Natural "Félix de Azara," Buenos Aires, Argentina ³Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Argentina