New conifer fossil woods and leafy shoots from the uppermost Cretaceous of Patagonia (Río Negro Province, Argentina)

Abstract

Conifers are one of the most conspicuous elements in the Upper Cretaceous assemblages of Patagonia, with several taxa based on silicified woods, impressions/compressions and palynomorphs recorded. In this contribution, we describe new remains from two emblematic Campanian?–Maastrichtian units (i.e., Allen and Los Alamitos formations) from the Río Negro Province, Argentinian Patagonia. From the Allen Formation, we present two fossil wood taxa, Brachyoxylon raritanense Torrey 1923 and Agathoxylon? sp. that weren’t previously recognized in the unit. Additionally, two types of silicified leafy shoots, referred to Brachyphyllum sp. 1 and B. sp. 2 are described, these being the first leaf fossils for the unit. From the Los Alamitos Formation, we present the first macrofloristic remains known for the unit, represented by Podocarpoxylon mazzonii (Petriella) Müller-Stoll et Schultze-Motel 1990, an emblematic species present in Campanian to Paleocene assemblages of Patagonia. These new records add new information on the paleofloras that thrived in Patagonia during the latest part of the Mesozoic Era and expand the geographic distribution of taxa that survived the end-Cretaceous mass extinction.