Myrtaceae pollen morphology study from Bass Strait islands, Australia, is effective in separating region-specific fossil Myrtaceae pollen types

The identification of Myrtaceae pollen to species level in fossil records has challenged palynologists due to the similarity of pollen grains produced by species in this family. Here, we present a pollen morphological study of the Myrtaceae species found in a specific region of southeastern Australia, the islands of the Furneaux Group in Bass Strait, and apply this to fossil pollen records from the same region to confirm its utility in differentiating Myrtaceae pollen to type level. We examined 23 species of Myrtaceae, belonging to 6 genera, and were able to identify 11 distinct types. The observed Myrtaceae pollen taxa can be confidently separated to genus level, apart from Euryomyrtus, which is indistinguishable from Leptospermum. Specifically, separation to species level is most achievable within the genus Melaleuca, as well as Kunzea and Calytrix, which are each represented by a single species. Conversely, Eucalyptus could only be separated into major types, while Leptospermum species could not be clearly separated, although differences in exine patterns exist. We also demonstrate that our pollen morphological types can be applied to Holocene and Pleistocene fossil records from the Furneaux Group. We recommend that studying the Myrtaceae of a specific area is more helpful in identifying fossil Myrtaceae pollen from that area than using general Myrtaceae pollen morphological descriptions or keys that are not site- or region-specific.