Resumen

PUJANA, Roberto R. Fossil woods from the Oligocene of southwestern Patagonia (Río Leona Formation): Rosaceae and Nothofagaceae. Ameghiniana [online]. 2009, vol.46, n.4, pp.621-636. ISSN 1851-8044.

Systematic studies of angiosperm fossil woods from sediments of the Río Leona Formation were continued. A new morphospecies of Maloidoxylon with affinity to Rosaceae was described and constitutes, together with the fossil pollen from the same strata, the oldest South American fossil with this familial affinity. Nothofagaceae fossil woods are represented by the morphospecies Nothofagoxylon scalariforme Gothan, Nothofagoxylon kraeuseli Boureau et Salard, Nothofagoxylon triseriatum Torres et Lemoigne, Nothofagoxylon ruei Salard and a new morphospecies of Nothofagoxylon. Three of the four subgenera of Nothofagus were recognized in the fossil woods and a new infrageneric affinity for Nothofagoxylon ruei was proposed. The described woods have affinity to extant genera and species that inhabit Patagonia, except for the Rosaceae wood where the generic affinity is not well-established.

Palabras clave : Wood anatomy; Patagonia; Oligocene; Secondary xylem; Rosaceae; Nothofagaceae.