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The monocot family Cyclanthaceae (Pandanales) comprises ca. 230 known species in 12 genera restricted to the Neotropics. The family has not been the subject of a species‐level molecular phylogenetic study to date, with multiple evolutionary and biogeographic questions about Cyclanthaceae still unanswered. In this study, we address genus‐ and species‐level relationships and the historical biogeography of Cyclanthaceae based on a broadly sampled molecular phylogeny. Two low‐copy nuclear genes (phyC, rpb2) and five plastid regions (atpB‐rbcL, psbA‐trnH, trnL‐trnF, trnQ‐rps16, matK) representing 99 species and all genera of Cyclanthaceae were sampled, spanning the taxonomic and biogeographic diversity of the family. Our results strongly support the monophyly of all Cyclanthaceae genera and confirm previously proposed hypotheses of intergeneric relationships. Infrageneric relationships are generally well supported, with some exceptions in the genus Asplundia that may require a broader sampling to clarify. The early diversification of Cyclanthaceae is estimated to date back to the Paleocene‐Eocene period in South America, where the family possibly arrived through a boreotropical route. The origin of most genera is inferred from the Paleocene of the Tumbes‐Chocó‐Magdalena region, possibly indicating an earlier origin for this biodiversity hotspot. The current distribution of Cyclanthaceae is likely to have been strongly influenced by major biogeographical events in the Neotropics, such as the uplift of the Andes and the opening of the South America dry diagonal. Further studies that include a broader sample of the large Asplundia‐Dicranopygium clade and Sphaeradenia group are required. [ABSTRACT FROM AUTHOR]

Premise of research. The opening of the Drake Passage in the Miocene (disconnecting Antarctica and South America and resulting in the establishment of the Circumpolar Current preventing warm waters from the north to reach the polar continent) has led to the formation of the ice sheets and the retreat of the temperate to tropical vegetation that had covered Antarctica for millions of years. With only two current native vascular plant species, Antarctica has been virtually ignored in biogeographical reconstructions and, when considered, only a posteriori invoked as a route of dispersal to reconcile inferred disjunct biogeographical patterns. Methodology. Here, we provide a brief overview of the rich fossil record of Antarctica, further confirming that many plant families were once present on this continent and that the age of a family is mostly not correlated with its presence or absence on the continent. Such evidence indicates a need to develop a paleogeographical model incorporating Antarctica that can be applied to constrain ancestral area reconstructions. We propose such a model and investigate its effects on biogeographical scenarios using the cosmopolitan plant family Myrtaceae (a family with a rich fossil record in Antarctica) as a case study. Pivotal results. Based on this evidence and previous studies that have shown the importance of Antarctica in the biogeography and evolution of plant lineages, we argue that this region should routinely be included as a predefined area in biogeographical analyses. Conclusions. A possible paleogeographical model including Antarctica is proposed. It is subdivided into five time slices and spans the last 160 Myr. We expect that the formal inclusion of Antarctica in ancestral area reconstructions (using an evidence-based biogeographical model) will open further discussions and research programs assessing the importance of this area in shaping the current temperate and tropical floras and increase the precision of resulting biogeographical patterns. [ABSTRACT FROM AUTHOR]