First fossil woods and palm stems from the mid‐Paleocene of Myanmar and implications for biogeography and wood anatomy

Abstract

PremiseThe rise of angiosperm‐dominated tropical rainforests has been proposed to have occurred shortly after the Cretaceous‐Paleogene transition. Paleocene fossil wood assemblages are rare yet provide important data for understanding these forests and whether their wood anatomical features can allow us to document these changes.MethodThe anatomy of eleven specimens of Paleocene‐age is described using standard terminology and their affinities to present‐day taxa is investigated.Key resultsWe report here the first middle Paleocene fossil wood specimens from Myanmar, which was near the equator and anchored to India at that time. Some fossils share affinities with Arecaceae, Sapindales (Anacardiaceae, Meliaceae) and Moraceae and possibly Fabaceae or Lauraceae. One specimen is described as a new species and genus: Compitoxylon paleocenicum gen. et sp. nov.ConclusionsThis assemblage reveals the long‐lasting presence of these aforementioned groups in South Asia and suggests the early presence of multiple taxa of Laurasian affinity in Myanmar and India. The wood anatomical features of the dicotyledonous specimens reveal that both “modern” and “primitive” features (in a Baileyan scheme) are present with proportions similar to Paleocene Indian localities. Their anatomical diversity corroborates that tropical flora display “modern” features early in the history of angiosperms, and that their high diversity remained steady afterwards.This article is protected by copyright. All rights reserved.