Sunday 29 June 2014

A Chacoan Peccary from the Late Pleistocene of northern Uruguay.

The Chacoan Peccary (Catagonus wagneri) was first recorded from pre-Columbian archaeological sites in northern Argentina in 1930, and subsequently found to be still living in the dry Chacos thorny forests of northern Argentina, western Paraguay and southeastern Bolivia in the 1970s. The Chacos Forests are hot and dry, with average annual temperatures over 24˚C and average annual rainfall between 80 and 800 mm. The two archaeological sites in northern Argentina where Catagonus wagneri has been recorded are outside the Chacos Forests, but are relatively close and still within areas with a hot dry climate; both are about a thousand years old.

In a paper published in the journal Historical Biology on 18 December 2012, Germán Mariano Gasparini of the División Paleontología Vertebrados at the Museo de La Plata, Martín Ubilla of the Facultad de Ciencias at the Universidad de la República and Eduardo Pedro Tonni, also of the División Paleontología Vertebrados at the Museo de La Plata, describe the skull of a Choacan Peccary from the Late Pleistocene Sopas Formation in Artigas Department in northern Uruguay. 

The specimen comprises a partial skull covered in carbonaceous material (limestone) with most of its teeth intact. The skulls of Catagonus wagneri are quite distict, and there is no doubt about the assignation of this specimen to the species.

Specimen assigned to Catagonus wagneri: (a) Lateral view. (b) Palatal view. (c) Occlusal view of right P2-M3 series. Gasparini et al. (2012).

The Sopas Formation outcrops along streams and rivers in northern Uruguay. It is about 15 m thick and comprises brownish mudstones, siltstones, sandstones and occasionally conglomerates. It has not been dated precisely, but based upon biostratigraphical evidence it is Late Pleistocene, and probably predates the last Glacial Maximum. It has previously yielded other fossils associated with dry climates, such as Camelids and Guinea Pigs, but also species associated with much wetter environments, such as Otters, Tapirs and Capybaras, suggesting that the climate varied considerably during the time period when it was laid down.

Archaeological and paleontological sites where fossil remains of Catagonus wagneri were found and current range. (1) Llajta Maüca archaeological site, 15 km north-west of Melero, Santiago del Estero Province. (2) Tulip-Loman archaeological site, near Icano, Santiago del Estero Province, 45 km south of Llajta Maüca. (3) Paleontological site in the Cuareim river, Artigas Department, Uruguay. (a) Mariscal Estigarribia, Boquerón Department, Paraguay. (b) Las Lomitas, Formosa Province, Argentina. Grey area: current range of Catagonus wagneriGasparini et al. (2012).

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