RESUMO
⢠Premise of the study: As currently circumscribed, Lastreopsis has about 45 species and occurs in Australia, southern Asia, Africa, Madagascar, and the neotropics. Previous molecular phylogenetic studies suggested that Lastreopsis is paraphyletic. Our study focuses on resolving relationships among the lastreopsid ferns (Lastreopsis, Megalastrum, and Rumohra), the evolution of morphological characters, and an understanding of the temporal and spatial patterns that have led to the current diversity and geographical distribution of its extant species.⢠Methods: Phylogenetic relationships were recovered under Bayesian, maximum likelihood, and maximum parsimony methods, using a data set of four plastid markers. Divergence time estimates were made using BEAST, and the biogeographic hypotheses were tested under the DEC model and the RASP/S-DIVA methods.⢠Key results: Lastreopsis was recovered as paraphyletic, and at least one of its clades should be recognized as a distinct genus, Parapolystichum. Coveniella poecilophlebia and Oenotrichia tripinnata were nested within Lastreopsis s.s., Megalastrum and Rumohra as sister to the Lastreopsis s.s., and the Lastreopsis amplissima clades. The initial diversification of the lastreopsids took place at about 56.55 Ma, from a neotropical ancestor.⢠Conclusions: Taxonomic recognition of Parapolystichum is warranted to preserve the monophyly of Lastreopsis. Diversification among the main clades of the lastreopsid ferns was influenced by climatic and geological changes in the southern hemisphere. The biogeographic history of the group is intimately related to the trans-Antarctic corridor between Australia and South America, with evidence for multiple lineage interchanges between Australia and South America during the Oligocene and the Eocene epochs.
RESUMO
We performed a phylogenetic analysis of the fern genus Elaphoglossum using two non-coding chloroplast spacers: trnL-trnF and rps4-trnS. The sampling includes 123 species, of which 80 have not been previously sequenced, and for the first time includes species from Africa and the Indian Ocean area. The results of this expanded study largely agree with an earlier molecular study based on a smaller group of neotropical species and with the morphology-based classification of Mickel and Atehortua. We found, however, that some infrageneric groups such as section Elaphoglossum are not monophyletic. Besides section Elaphoglossum pro parte, we recognize six sections: two new monospecific, unnamed sections, and the previously established sections Lepidoglossa, Squamipedia, Amygdalifolia, and "Subulate-scaled clade." We divide the subulate-scaled clade into subsection Setosa (hydathodes present) and Polytrichia (hydathodes absent), and section Elaphoglossum is divided into subsections Platyglossa and Pachyglossa, two groups that do not appear to be supported by any single morphological character. In general, however, the main clades are supported by morphology. Finally, we discuss the species of the Indian Ocean region and their affinities with the neotropical ones. Out of the 11 species pairs postulated by Moran and Smith on the basis of morphology, two are well supported (E. eximium-E. aubertii; E. piloselloides-E. spatulatum) and three are not supported (E. ciliatum-E. humbertii; E. muscosum-E. poolii; E. paleaceum-E. deckenii), and two remain unresolved (E. erinaceum-E. hybridum; E. glabellum-E. acrostichoides) because our molecular markers were not variable enough. Four species pairs could not be tested because specimens were lacking. Unsupported species pairs are best interpreted as morphological convergences. Two additional species pairs are proposed: E. cuspidatum-E. succisaefolium; E. doanense-E. hornei. Placement of the species from the Indian Ocean suggests that at least 13 long-distance dispersal events occurred between the Neotropics and the Indian Ocean-Africa.