Coniferous woods and wood decaying basidiomycetes from the El Freno Formation (Lower Jurassic), Atuel Valley, north of the Neuquén Basin, Mendoza Province, Argentina

SILVIA GNAEDINGER; JUAN GARCÍA MASSINI; FLORENCIA BECHIS; ANA MARÍA ZAVATTIERI

AMEGHINIANA

ASOCIACION PALEONTOLOGICA ARGENTINA

Lugar: Buenos Aires; Año: 2015 vol. 52 p. 447 - 467

0002-7014

Two species of coniferous silicified wood are described from the El Freno Formation (Lower Jurassic) at Cerro La Brea, on the southern margin of the Atuel River, southern Mendoza Province, Argentina. Agathoxylon liguaensis Torres and Philippe (Araucariaceae) and the new species Podocarpoxylon atuelensis sp. nov. (Podocarpaceae) were described based on a detailed description of the secondary xylem. Wood specimens are well preserved, although some sections display variably decaying cell-walls typical of white-rotting by extant fungi. Vegetative and sexual structures in the degraded areas are identifiable as basidiomycetes. This is consistent with fungal saprotrophism and supports the role of fungi in the recycling of the organic matter in Mesozoic terrestrial ecosystems. Considering the available geochronologic and biostratigraphic data and the current lithostratigraphic settings proposed for the unit, the age of the El Freno Formation at the studied locality can be constrained to the Hettangian-Sinemurian.