New Pliocene records of plant fossil-taxa from NW Portugal and their relevance for the assessment of diversity loss patterns in the late Cenozoic of Europe

Abstract

The section of São Pedro da Torre (NW Portugal) is relevant because its rich pollen content, chronologically correlated to the late Pliocene assemblages of the reference section of Rio Maior. The purpose of this study was to carry out, for the first time in the area, a taxonomic analysis of the carpological remains and integrate the results with those of the previous palynological studies. Our carpological analysis pointed out several taxa not recorded previously in the area, mostly belonging to genera extirpated from Europe, such as Azolla cf. aspera, Hypericum tertiaerum, Itea europaea, Eurya stigmosa, Proserpinaca reticulata, Symplocos casparyi, Symplocos germanica and Tetraclinis salicornioides. This taxonomic composition was only detected in Piacenzian deposits from Italy, the area of southern Europe where the chronological sequence of fruit and seed assemblages is less discontinuous. For most of these taxa the occurrence at São Pedro da Torre constitutes a westward extension of the distribution during Neogene. Symplocos germanica occurs for the first time in the Pliocene and is recorded much more westwards and southwards than previously known. The integrated plant record shades light on the vegetation, paleoenvironments and plant extirpation patterns throughout the Pliocene in the Iberian Peninsula. Although limited, the results from this contribution are intended to stimulate the search for fruit and seed assemblages in Portugal as well as in similar poorly studied areas, where Pliocene successions keep a future potentiality in documenting further the late occurrences in Europe of extirpated plant taxa, which are relevant for paleoclimatic and biogeographic reconstructions.