Taxaceoxylon katuatenkum sp. nov. en la Formación Koluel-Kaike (Eoceno inferior - medio), Chubut, Argentina: un componente de los bosques subtropicales paleógenos de Patagonia

this paper describes a silicified trunk fragment, taxaceoxylon katuatenkum sp. nov., collected from kilómetro 170 locality, se of sarmiento city (chubut, argentina). this fossil stem is the second record in argentina of the taxaceoxylon genus, and comes from pyroclastic sediments of the lower - middle eocene koluel-kaike formation of central patagonia. this fossil record indicates that the taxaceae and/or cephalotaxaceae families were more widespread in the past than today and that these families were not confined to the northern hemisphere. according to the paleobotanical and paleopedological information of the koluel- kaike formation, this new taxon of taxaceae and/or cephalotaxaceae would have been a component of the forests developed in humid and warm environments of central patagonia during the lower - middle eocene. this subtropical flora expanded in south america at mid latitude (47o s), represents the transition between the rainforests and dry forests (megathermal palaeocommunities) during the early eocene climatic optimum (eeco), and the savannas with palms and grasslands developed by the middle - late eocene.