Evidence of large Anacardiaceae trees from the Oligocene-early Miocene Santiago Formation, Azuero, Panama

We have poor knowledge of the plants that inhabited Central America during the Cenozoic. One of the families with a rich fossil record worldwide, especially for the Oligocene and Miocene epochs is Anacardiaceae. Llanodelacruzoxylon sandovalii gen. et sp. nov. is the first formal record of a fossil wood of Anacardiaceae found in Panama and Central America to date. We collected the fossil woods in the Oligocene-Miocene Santiago Formation, in the Azuero Peninsula, Panama. Among the samples collected we have described and identified this new fossil genus of Anacardiaceae, using wood anatomical characters and extensive comparisons with fossil and extant material. These two specimens share diagnostic features with several Anacardiaceae woods, such as: large vessels (>200 μm), simple vessel-ray pitting and rays mostly uniseriate with large crystals. The occurrence of these Anacardiaceae in Panama by the Oligocene to Miocene adds to the understanding of the historical biogeography of the family and supports Central America (including Mexico) being a divergence center of the Anacardiaceae.