Loxopterygium wood in Coayuca de Andrade, Oligocene of Puebla, Mexico

• A new species of Loxopterygium is described.
• Oligocene Anacardiaceae in the Neotropical Flora of Mexico.
• Plants expanding distribution area from North to South America during the Cenozoic.
• Anacardiaceae diversity in the Cenozoic of Mexico keeps growing.

A wood type preserved in Oligocene sediments of Coayuca de Andrade, Puebla, Mexico, is described and compared to Loxopterygium Hook. f. (Anacardiaceae). Among the characters that sustain this assignment are growth rings are marked by 2–3 rows of flattened latewood fibers. The vessel elements are circular to oval, predominantly solitary and radial multiples of 2 and 3. The perforation plates are simple, intervascular pits are alternate, oval and polygonal, with lenticular apertures, some of them are coalescent. Axial parenchyma is paratracheal scanty. Rays correspondent to the heterogeneous Kribs type IIB and one to two radial canals occur in multiseriate rays. These same characteristics are important to distinguish it from the extant species in the genus and support the recognition of a new species, Loxopterygium andradensii Méndez-Cárdenas et al. The presence of this new species in the Cenozoic of Mexico confirms the importance of Anacardiaceae in the flora and vegetation of low latitude North America, reinforcing the idea that some elements of the Neotropical flora were in North America before the Plio-Pleistocene Great Biotic exchange and that at some point it was important for the diversification of some taxa.