Phylogeny and biogeography of exindusiate Andean Polystichum (Dryopteridaceae)

Abstract

The monophyletic exindusiate Andean Polystichum lineage diverged from a Mexican lineage in the middle Miocene and diversified in the central Andes before dispersing northward. This south-to-north dispersal pattern, documented for many other Andean lineages, corresponds with episodes of uplift in the tropical Andes.

A well-sampled phylogenetic analysis of the polystichoid ferns (Dryopteridaceae) suggests a complex biogeographical history involving both boreotropical migrations and recent transoceanic dispersals

“…By extending the sampling, we have been able to reconstruct a worldwide, time-calibrated phylogeny for this large group of ferns. Phylogenetic relationships are generally congruent with previous studies (Driscoll and Barrington, 2007;Little and Barrington, 2003;Lu et al, 2007;McHenry and Barrington, 2014). However, the monophyly of Polystichum still remains unresolved.…”

“…Previous studies on polystichoid ferns focused mainly on a specific geographical region and/or were based on limited taxon and character sampling (Li et al, 2008;Lu et al, 2007;McHenry and Barrington, 2014). Therefore, phylogenetic relationships and its biogeographical history were only partly elucidated.…”

“…The monophyly of polystichoid ferns is not in doubt (Driscoll and Barrington, 2007;Li et al, 2007;Little and Barrington, 2003;Lu et al, 2007;Schuettpelz and Pryer, 2008;McHenry and Barrington, 2014;Le Péchon et al, 2016) and unlike most other fern taxa, Polystichum has been a subject of several previous biogeographical analyses (e.g., Perrie et al, 2003;Li et al, 2004Li et al, , 2007Driscoll and Barrington, 2007;McHenry and Barrington, 2014). Polystichum may have originated in (i) Asia ca.…”

“…75 Ma ago (Li et al, 2008(Li et al, , 2004), (ii) may then have migrated to Australasia in the middle Miocene Perrie et al, 2003); (iii) and colonized Hawaii at least two times (Driscoll and Barrington, 2007). Recently, McHenry and Barrington (2014) showed that the exindusiate Andean Polystichum diverged from a Mexican lineage during the middle Miocene. However, all previous phylogenetic and biogeographical studies on the polystichoid ferns focused on specific geographical regions and were based on limited taxon and character samplings (Driscoll and Barrington, 2007;Li et al, 2008Li et al, , 2007Li et al, , 2004Lu et al, 2007;McHenry and Barrington, 2014;Perrie et al, 2003).…”

“…Recently, McHenry and Barrington (2014) showed that the exindusiate Andean Polystichum diverged from a Mexican lineage during the middle Miocene. However, all previous phylogenetic and biogeographical studies on the polystichoid ferns focused on specific geographical regions and were based on limited taxon and character samplings (Driscoll and Barrington, 2007;Li et al, 2008Li et al, , 2007Li et al, , 2004Lu et al, 2007;McHenry and Barrington, 2014;Perrie et al, 2003). Large-scale analyses using a worldwide time-calibrated phylogenetic framework to trace the biogeographical history of the polystichoid ferns are still lacking except a recent study by Le Péchon et al (2016) which focused on testing the morphology-based classifications.…”