GUAYCURUAN, an independent linguistic stock of South American Indians, so called from the Guaycurus, its best known tribe. The tribes of this stock lived in the Argentine Chaco in the region west of the Parana and Paraguay rivers, from a little above Santa Fe nearly to the mouth of the Pilcomayo and extending westward north of the Salado river, nearly to the foothills of the Andes. After the early period of Spanish settlement, the Guaycu ruan tribes expanded eastward some distance across the Parana be low Corrientes, and further north, penetrated into southern Matto Grosso in Brazil. The Toba are the best known tribe of the stock to-day, the Abipones (q.v.), made famous by the missionary Dobrizhoffer in the 18th century, being now extinct.
See D. G. Brinton, "The Linguistic Cartography of the Chaco Region" (Proc. Amer. Philos. Soc. vol. xxxvii.) ; L. Kersten, "Die Indianerstamme des Gran Chaco," etc. (Internet. Archie. f iir Ethno graphic, vol. xvii. pp. 1-75).