Early Cretaceous Brachyoxylon woods from Argentinean Patagonia and comments on the Cheirolepidiaceae distribution

We studied fossil woods from Matasiete and Castillo Formations (Aptian-Albian) for the first time. The woods, preserved in fluvial channel and floodplain deposits, have anatomy consistent with the fossil-genus Brachyoxylon Hollick and Jeffrey. Specimens from Castillo Formation have poorly distinct growth ring boundaries, exclusively uniseriate with a mixed arrangement intertracheary radial pitting, araucarioid cross-field pitting with 3-8 half-bordered pits with oblique aperture, and uniseriate rays. Specimens from Matasiete Formation are poorly preserved and only one could be assigned to Brachyoxylon with reservations. Brachyoxylon is a fossil-genus with a worldwide distribution and related to the fossil family Cheirolepidiaceae, a group of conifers that developed in various environments. However, our study suggests that this family would have prospered in locally semi-arid conditions.