The fern Konijnenburgia alata in the mid-Cretaceous of Patagonia, and the Matoniaceae fossil record

Abstract Based on new material from the uppermost Albian levels of Piedra Clavada Formation (Austral Basin, Argentina), the species Konijnenburgia alata (Matoniaceae) is re-examined, its diagnosis emended, and a formal lectotype from the historic type collection is here designated. A complete comparison with extant and fossil Matoniaceae is provided, with discussions about synonymies among fossil genera. The Matoniaceae megafossil records possess a Cretaceous acme in the Albian-Cenomanian with a cosmopolitan distribution. Its conspicuous macro and microfossil record from southern Patagonia is coherent with this fact. Reports of fossil Matoniaceae decrease following the Turonian, likely related to global temperature fall and/or increase of the angiosperm abundance and diversity in the floristic assemblages.