Pliocene Lythrum (loosestrife, Lythraceae) pollen from Portugal and the Neogene establishment of European lineages

Abstract

The fossil record of Lythrum is scarce and every new find brings an extra piece of the puzzle to the obscure phytogeographic history of this genus. Lythrum pollen is unique and has the potential to be recognized in palynological assemblages. Therefore, the few pre-Holocene fossil records are all pollen described from North America, Russia, and Europe. The European records are both most numerous and geologically younger than those from other parts of the Northern Hemisphere. Earliest European Lythrum pollen records are of late Miocene age and parallel to starting crown group radiation in the Eurasian clade of Lythrum. European Miocene to Pliocene Lythrum pollen morphology is comparable to that of extant species. Interestingly, the late Miocene expansion of Lythrum into Europe coincides with the decline of Decodon, and Lythrum appears to replace Decodon in late Neogene fossil palynological assemblages.