First fossil record in Tamberia formation (Neogene) in Bolson de Fiambala, Catamarca province, Argentina: Palaeoenvironmental inferences through Leguminosae woods

摘要

The aim of this study is to report the first fossil wood record of Leguminosae in miocene sediments from Tamberia Formation outcropping in the center-west of Catamarca province, Argentina. This Leguminosae specimen was found on levels of multi-colored sandstones that alternated with dark brown pelites and gray conglomerates. It is characterized by the presence of: semi-ring porous wood with vestured ornamented pits, helicoidal thickenings on the vessel walls, paratracheal parenchyma, homogeneous and multiseriate rays, all of which justify its assignment to Gleditsioxylon Muller-Stoll and Ma center dot del. Six species are known and distributed in: Argentina, the United States, China and Japan in Miocene sediments coetaneous with sediments from Tamberia Formation. The fossil wood specimen documented in this study is assigned to Gleditsioxylon fiambalense nov. sp. taking into account the combination of its anatomical features. Vulnerability and mesomorphy indices reveal its subtropical environmental condition which is not only typical of Gleditsia amorphoides, the current species, but also coincides with the palaeoenvironmental inferences derived from sedimentological research. This first paleontological record promises interesting analyses to understand the paleobiological and paleoecological aspects of the Tamberia Formation and adds another new evidence to show the diversity of the neogene Leguminosae lignofloras of northern Argentina.