Browsing by Author "Caro, Francisco J."

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    A Partially Complete Skeleton of Hippidion Saldiasi Roth, 1899 (Mammalia: Perissodactyla) from the Late Pleistocene of the High Andes in Northern Chile
    (2020) Labarca, Rafael; Caro, Francisco J.; Villavicencio, Natalia A.; Capriles, Jose M.; Briones, Esteban; Latorre, Claudio; Santoro, Calogero M.
    South America is well known for its abundance of Quaternary fossiliferous deposits, but well-preserved fossil remains from well-dated sites are scarce in the Atacama Desert and adjacent arid Andes. Here we report on a partially complete skeleton (46%) of a single young (ca. 3-4 years old) extinct horse discovered in the Salar de Surire, a salt flat located on the Andean altiplano of northern Chile (4,250 m asl). Comparative and osteometric morphological analyses identify the specimen as a South American endemic horse Hippidion saldiasi Roth, 1899. A direct AMS radiocarbon date on bone collagen yielded a calibrated age of 13,170 cal yr BP (2 sigma range: 13,300-13,060 cal yr BP) indicating that it lived near the end of the last glaciation. The body mass of the individual was calculated at approximately 326.4 kg, close to the upper limit of the larger sizes reported for the genus. Stable isotope evidence shows that the Salar de Surire horse relied on an almost 100% C3 diet that is mostly consistent with Hippidion specimens from other environments that also consumed either mixed C3/C4 or fully C3 diets. This finding is now the southernmost high-elevation record for this species and provides further evidence for the broad geographic and ecological distribution of this genus throughout southern South America.
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    First record of cf. Aenocyon dirus (Leidy, 1858) (Carnivora, Canidae), from the Upper Pleistocene of the Atacama Desert, northern Chile
    (2022) Caro, Francisco J.; Labarca, Rafael; Prevosti, Francisco J.; Villavicencio, Natalia; Jarpa, Gabriela M.; Herrera, Katherine A.; Correa-Lau, Jacqueline; Latorre, Claudio; Santoro, Calogero M.
    Fossil records of canids are rare and incomplete in South America. In Chile, all well-identified taxa are part of the "South American Canid Clade" and come from sites located in southern Patagonia. Here, we report the first record for Chile of a taxon of the "Canis clade," assigned to cf. Aenocyon dirus. The fossil remains consist of a partially complete left hind limb, exposed by aeolian deflation, which facilitated its discovery at an isolated setting in Quebrada Mani, named QM38 site, in the southern sector of the Pampa del Tamarugal basin, part of the hyperarid core of the Atacama Desert, northern Chile. Measurements of the fossil are larger than the Protocyon troglodytes, falling in the smaller size range of A. dirus and within the larger range of Theriodictis platensis. Its morphological features compared with bone references of large extinct canids show that the fossil belongs to a small-sized Aenocyon. The remains occur in surface silty clays deposited by an alluvial fan that was active in the Pampa del Tamarugal basin in the Late Pleistocene. A radiocarbon date from bone apatite yielded an age of 14,660 cal years BP, placing it within the first half of the Central Andean Pluvial Event when this basin was wetter, well vegetated, and inhabited by large, medium, and small herbivores. No other large predator records are known from this basin, and our find affords a more complete view of this ecosystem which thrived in the hyperarid core of the Atacama during the Late Pleistocene.
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    Written in bones: palaeoclimate histotaphonomic history inferred from a complete Megatherium skeleton preserved in the Atacama Desert
    (2025) Straulino Mainou, Luisa; Correa‐Lau, Jacqueline; Labarca Encina, Rafael; Villavicencio, Natalia A.; Standen, Vivien G.; Monsalve, Susana; Ugalde, Paula C.; Sedov, Sergey; Pi Puig, Teresa; Loredo‐Jasso, Alan Ulises; Caro, Francisco J.; Jarpa, Gabriela M.; Hernández‐Michaud, Patricia; Latorre H., Claudio; Santoro, Calogero M.
    A nearly complete and relatively well-preserved skeleton of the giant ground sloth Megatherium sp. in the hyperarid core of the Atacama Desert reveals how climate related taphonomic processes drastically transformed these remains over time. The individual, semi-exposed in situ by wind erosion, was found in late Pleistocene palaeowetland sediments that formed during the Central Andean Pluvial Event. Several radiocarbon dates on bone bioapatite and car bonate tufas date the specimen to c. 16500calyrBP. Physi cal, organic, and inorganic traces were identified using histotaphonomic, mineralogical, and microscopic analyses (optical, scanning electron and petrographic microscopy, x-ray diffraction and FTIR-ATR). Surficial bones with rounded, polished surfaces due to wind erosion are well pre served, while buried bones are poorly preserved and structu rally weak due to an early phase of bioerosion, which was followed by desiccation revealed by micro-cracks. Iron and manganese were deposited under anoxic conditions, followed by carbonates such as sparite and micrites, which formed due to a drier context, resulting in the encrustation of these bones by halite and calcium sulfates in hyperarid conditions that continue to this day. These observations imply that the ground sloth lived in a much wetter environment compared to today and its remains were subsequently affected by anae robic wet cycles, an oxidizing sedimentary environment, and later an oxidizing hyperarid climate. In summary, the unra velled histotaphonomy is written in small fractions of bones which emerge as new proxies for understanding the complex palaeoclimatic history of the Atacama Desert.