Origin of Hawaiian Polystichum (Dryopteridaceae) in the context of a world phylogeny

Abstract

A genus-wide molecular phylogeny for Polystichum and allied genera (Dryopteridaceae) was reconstructed to address the biogeographic origin and evolution of the three Hawaiian Polystichum species, all endemic there. The analysis was based on the cpDNA sequences rbcL and the trnL-F spacer from a taxonomically and geographically diverse sample. Parsimony and Bayesian phylogenetic analyses of the combined data support a monophyletic Polystichum and corroborate recent hypotheses as to membership and sequence of origin of the major groups within the genus. The Hawaiian Polystichum species are polyphyletic; two separate lineages appear to have arrived independently from the Old World. The provenance of the diploid Polystichum hillebrandii is continental eastern Asia, while the source of the polyploid lineage comprising tetraploid P. haleakalense and octoploid P. bonseyi is likely continental Asia. From our results, the origin of the Hawaiian species of Polystichum, like many Hawaiian fern genera with several species, is the result of multiple migrations to the islands, rather than single migrations yielding nearly all the local diversity as in the angiosperms. This emerging pattern provides a modern test of the premise that propagule vagility has a central role in determining pattern of evolution.

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

“…A more detailed analysis of these genera will be published separately. Based on previous molecular (e.g., Little and Barrington, 2003;Li et al, 2004Li et al, , 2008Driscoll and Barrington, 2007;Schuettpelz and Pryer, 2007;Lu et al, 2007;Liu et al, 2007) and morphological studies (Smith et al, 2006;Zhang et al, 2013), four species of Elaphoglossum Schott, two of Mickelia R.C. Moran, Labiak & Sundue, one of Bolbitis Schott, eight of Dryopteris Adans., four of Arachniodes Blume, and two of Polystichopsis (J.…”

“…In this study, we focus on the polystichoid ferns (Driscoll and Barrington, 2007;Little and Barrington, 2003;Schuettpelz and Pryer, 2007), namely Cyrtomium C. Presl, Phanerophlebia C. Presl, and Polystichum Roth (sensu Zhang, 2012;Zhang and Barrington, 2013a)., Polystichum is one of the most diverse fern genera, with about 500 species distributed worldwide but more common in temperate and subtropical regions (Zhang and Barrington, 2013a). The highest diversity is undoubtedly found in East Asia (e.g., 208 spp.…”

“…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.…”

“…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.…”

“…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.…”