Paleontologists have uncovered the fossilized decrease proper canine of a giant proborhyaenid sparassodont within the Taubaté Basin of Brazil.
The correct decrease canine of a giant proborhyaenid sparassodont from the Tremembé Formation, Brazil. Scale bars – 5 mm in (A-E) and 20 mm in (H). Picture credit score: Rangel et al., doi: 10.4072/rbp.2025.2.0534.
The brand new fossil dates again to the Deseadan age of the Oligocene epoch, between 29 and 21 million years in the past.
The specimen is assigned to a yet-to-be-named member of the Proborhyaenidae, an extinct household of South American metatherian mammals throughout the order Sparassodonta.
These creatures occupied the function of carnivorous predators on the continent through the Cenozoic period.
“Sparassodonta is an extinct clade of metatherians endemic to South America that introduced the principle terrestrial mammalian predators on this continent throughout Cenozoic occasions,” mentioned Dr. Caio César Rangel, a paleontologist with the Universidade Federal de Uberlândia and the Universidade Federal de Pernambuco, and colleagues from Brazil.
“Their evolution included two main diversification occasions, firstly within the Eocene and posteriorly within the Miocene.”
“The Oligocene is characterised by decrease temperatures in comparison with the Late Eocene and Miocene.”
“This world cooling occasion led to vital environmental modifications, which in flip brought on a faunal turnover in South America, together with the extinction and diversification of a number of metatherian clades.”
Life reconstruction of Thylacosmilus atrox, a species of saber-toothed metatherian mammal that belonged to the sister lineage of the Proborhyaenidae. Picture credit score: Roman Uchytel.
The paleontologists collected the brand new specimen, which is 5.73 cm (2.3 inches) in size, from the decrease a part of the Tremembé Formation within the japanese State of São Paulo, Brazil.
“The Taubaté Basin is situated within the State of São Paulo in southeastern Brazil and extends from the municipalities of Cachoeira Paulista to Jacarei,” they mentioned.
“It’s roughly 150 km (93 miles) in size and 10 to twenty km (6-12 miles) in width, in a graben between the mountain vary of Serra do Mar and Serra da Mantiqueira.”
“The Tremembé Formation is the one Late Oligocene fossiliferous unit in Brazil that preserves mammal fossils, with a various fauna and autochthonous species,” they added.
“The fauna from this locality is represented by Metatheria, Chiroptera, Rodentia, Cingulata, Astrapotheria, Litopterna, Notoungulata, and Pyrotheria.”
The traditional predator doubtless lived within the swamp/lacustrine setting and occupied the function of apex predator.
“The procumbence noticed within the canine related to evident put on within the crown, suggests a frequent use most likely associated to the seize or lively processing of prey in an grownup particular person,” the researchers mentioned.
The invention extends the geographic distribution of the Proborhyaenidae and provides a second file of a member of this sparassodont household in Brazil.
“This file will increase the variety of enormous mammals within the Tremembé Formation,” the authors mentioned.
“Total, this locality is a major geological and paleontological useful resource that gives invaluable insights into the ultimate phases of the Paleogene interval in intertropical South America.”
The invention is described in a paper revealed in August 2025 within the journal Revista Brasileira De Paleontologia.
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C.C. Rangel et al. 2025. The ‘swamp monster’ of the Tremembé Formation (Taubaté Basin, Brazil; Late Oligocene): an outline of a carnivorous metatherian (Sparassodonta, Proborhyaenidae). Revista Brasileira De Paleontologia 28 (2): e20250534; doi: 10.4072/rbp.2025.2.0534
