A critical evaluation of fossil pollen records from the mangrove tree Pelliciera beyond the Neotropics: Biogeographical and evolutionary implications

Abstract

Pelliciera is a Neotropical mangrove tree restricted to a small region around the Panama Isthmus. In the past, this taxon was distributed across much of the Neotropics, reaching its maximum extent during the Oligo-Miocene. The occurrence of Pelliciera outside the Neotropics had been debated based on a few fossil pollen records from Africa and Europe, though many of these records have been questioned. However, the recent proliferation of fossil pollen records identified as the fossil representatives of Pelliciera pollen warrants reconsideration. This paper provides a detailed review of the morphological features of extra-Neotropical records published to date, comparing them with extant Pelliciera pollen. Over 80 records from Africa, Europe, the Middle East, and North America were retrieved for this review. Only those published in Scopus-indexed journals are considered to avoid issues related to gray literature and predatory journals. Records mentioning purported Pelliciera fossils without providing material suitable for morphological comparison were also excluded, as were those featuring poor-quality images impossible to resolve. Among the records that met these criteria, only a subset of African fossil pollen types are compatible with Pelliciera: three with high reliability and another three with medium-high reliability, ranging from the Eocene to the Plio-Pleistocene. With these data, the occurrence of Pelliciera fossil pollen outside the Neotropics cannot be dismissed. However, the evidence remains insufficient to construct a transcontinental biogeographical and evolutionary framework for Pelliciera over time. Continued research in this direction is recommended, and suggestions for advancing this task are provided.