2026-10-14T07:23:58Z https://api.figshare.com/v2/oai

oai:figshare.com:article/33969224 2026-09-22T23:40:03Z category_1 category_915 category_16 category_24 category_272 category_873 category_39 category_734 category_61 category_62 category_106 category_132 category_133 category_135 category_140 portal_87 item_type_3 month_year_09_2026

A new sabre-toothed thylacosmilid (Thylacosmilidae, Metatheria) from the Pliocene–Pleistocene of Southern Buenos Aires Province, Argentina Eric N. del Campo (25092386) Federico L. Agnolín (3276420) Nicolás R. Chimento (22154069) Daniel Boh (25092389) Mariano Magnussen (25092392) Francisco De Cianni (25092395) Biophysics Physical Sciences not elsewhere classified Physiology Evolutionary Biology Environmental Sciences not elsewhere classified Chemical Sciences not elsewhere classified Ecology Biological Sciences not elsewhere classified Developmental Biology Marine Biology Science Policy Infectious Diseases Plant Biology Computational Biology Cardiology Sparassodonta postcranium Vorohué Formation Metatheria systematic palaeontology South America Thylacosmilids are a clade of metatherian predators known from lower Miocene to upper Pliocene strata of South America. They had highly specialized skulls with enlarged canines. Here, we describe remains of a new thylacosmilid taxon from the Argentine Pampas. This specimen comprises a partial postcranial skeleton from the upper Pliocene–Lower Pleistocene Vorohué Formation near Miramar in Buenos Aires Province. It shares several features supporting referral to Thylacosmilidae including a strong neck, robust forelimbs, and a shortened tibia. However, it shows notable differences from more derived thylacosmilids, especially Thylacosmilus atrox, the only thylacosmilid represented by relatively complete postcranium. The Vorohué Formation taxon differs by having a robust atlas, simpler ventral crest in the fifth cervical vertebra, enlarged medial epicondyle of the humerus, less distally projected capitulum, a more developed process on top of the lateral epicondylar crest, an enlarged radial fossa, deep coronoid fossa bordered by a marked ridge, smaller medial epicondyle on the femur, and a straight tibial shaft. These character states support establishment of a new genus and species. Phylogenetic analysis places the Vorohué Formation taxon as the sister of Thylacosmilus atrox. Functional comparisons suggest powerful neck musculature and forelimbs, coupled with low cursoriality—traits typical of ambush predators. The Vorohué Formation taxon is one of the geologically youngest sparassodonts, and shows that thylacosmilids coexisted not only with early North American placental carnivores (e.g., procyonids), but also probably mustelids and foxes. Eric del Campo* [<a target="_blank" href="mailto:eric.delcampo.93@gmail.com">eric.delcampo.93@gmail.com</a>], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Federico L. Agnolín [<a target="_blank" href="mailto:fedeagnolin@yahoo.com.ar">fedeagnolin@yahoo.com.ar</a>], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Fundación de Historia Natural “Félix de Azara”, Departamento de Ciencias Naturales y Antropología, Universidad Maimonides, Hidalgo 775, Buenos Aires, Argentina; Nicolás R. Chimento [<a target="_blank" href="mailto:nicochimento@hotmail.com">nicochimento@hotmail.com</a>], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Fundación de Historia Natural “Félix de Azara”, Museo de Ciencias Naturales y Arqueología “Prof. Manuel Almeida”, 25 de Mayo 533 (2820), Gualeguaychú, Entre Ríos, Argentina; Daniel Boh [<a target="_blank" href="mailto:dannyboh@gmail.com">dannyboh@gmail.com</a>], Museo Municipal Punta Hermengo, Vivero Dunícola Municipal “Florentino Ameghino”, Partido de General Alvarado, Miramar, Provincia de Buenos Aires, Argentina; Mariano Magnussen [<a target="_blank" href="mailto:marianomagnussen@yahoo.com.ar">marianomagnussen@yahoo.com.ar</a>], Laboratorio de Anatomía Comparada y Evolución de los Vertebrados, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina; Francisco De Cianni [<a target="_blank" href="mailto:deciannifrancisco@gmail.com">deciannifrancisco@gmail.com</a>], Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Av. Ángel Gallardo 470, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina. 2026-09-22T23:40:03Z Dataset Dataset 10.6084/m9.figshare.33969224.v1 https://figshare.com/articles/dataset/A_new_sabre-toothed_thylacosmilid_Thylacosmilidae_Metatheria_from_the_Pliocene_Pleistocene_of_Southern_Buenos_Aires_Province_Argentina/33969224 CC BY-NC-ND 4.0