First record of fossil Trachycarpeae in Africa: three new species of Palmoxylon from the Oligocene (Rupelian) Gebel Qatrani Formation, Fayum, Egypt

Abstract

Based on a survey of the fossil wood flora of Gebel Qatrani (Rupelian, Fayum, Egypt), three new species of palm stem are described: Palmoxylon araneus Nour-El-Deen, El-Saadawi & Thomas sp. nov., Palmoxylon elsaadawii Nour-El-Deen & Thomas sp. nov. and Palmoxylon qatraniense Nour-El-Deen, El-Saadawi & Thomas sp. nov. The specimens are the first petrified palm wood to be reported from the deposits in the upper sequence of the Gebel Qatrani Formation. They are characterized by fibrovascular bundles with two vessels, the presence of a ground parenchyma sustained growth, fibrous bundles, globular echinate phytoliths, radiating parenchyma, and multiseriate scalariform thickening of metaxylem elements. Palaeoclimatic inferences and comparisons with similar fossil stems are discussed for each of the three taxa. Comparisons with extant palms allow identification of these species to tribal (Trachycarpeae) and subfamilial (Coryphoideae) levels. They are the first representatives of tribe Trachycarpeae on the African continent. An attempt is also made to explain migration events and discuss the current and fossil distribution of the tribe in Africa.