Combretaceous fossil wood from Ituzaingó Formation (Late Miocene?), Argentina, indicate a coastal marine environment

Abstract

A new anatomical study of the fossil material assigned to Menendoxylon areniensis Lutz 1979 (family Fabaceae) was performed. In this study, new wood anatomical characteristics were observed. These are diagnostic characters present in the family, Combretaceae. Also, its presence suggests an adaptation to environmental variability: numerous vessels (mean 14–52 vessels/mm2), small vessel diameter (mean 26–103 μm), and low vessel height (mean 76–329 μm). The fossil is closest to the genera, Conocarpus and Laguncularia, with anatomical characteristics that are particularly similar to those of Conocarpus erectus. Conocarpus erectus is a species associated with mangroves and is classified as pseudo-mangrove or peripheral species. Mangroveoxylon areniensis gen. et comb. nov., recovered in the Late Miocene? of Ituzaingo Formation is the first record of fossil wood that indicates a coastal marine environment, which is further south of the tropics. This could resemble a tropical environment with species developing at different levels of the land.