Coniferous wood and wood decaying fungi from the El Freno Formation (Lower Jurassic), Neuquen Basin, Mendoza Province, Argentina

SILVIA C. GNAEDINGER; GARCIA MASSINI J.L.; FLORENCIA BECHIS; ANA M. 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 bank of the Atuel River, southern Mendoza Province, Argentina, i.e., Agathoxylon liguaensis Torres and Philippe (Araucariaceae) and Podocarpoxylon atuelensis sp. nov. (Podocarpaceae). Generic and specific assignments are based on features of the secondary xylem, i.e., radial pitting of tracheids, cross-fields and rays. Wood specimens are well preserved, although some sections display variably decayed 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.