Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4749720 | Palaeoworld | 2007 | 7 Pages |
Abstract
Polystichum, one of the largest genera of ferns, occurs worldwide with the greatest diversity in southwest China and adjacent regions. Although there have been studies of Chinese Polystichum on its traditional classification, geographic distributions, and even a few on its molecular systematics, its relationships to other species outside China remain little known. Here, we investigated the phylogeny and biogeography of the Polystichum species from China and Australasia. The evolutionary relationships among 42 Polystichum species found in China (29 taxa) and Australasia (13 taxa) were inferred from phylogenetic analyses of two chloroplast DNA sequence data sets: rps4-trnS and trnL-F intergenic spacers. The divergence time between Chinese and Australasian Polystichum was estimated. The results indicated that the Australasian species comprise a monophyletic group that is nested within the Chinese diversity, and that the New Zealand species are likewise a monophyletic group nested within the Australasian species. The divergence time estimates suggested that Chinese Polystichum migrated into Australasia from around 40Â Ma ago, and from there to New Zealand from about 14Â Ma. The diversification of the New Zealand Polystichum species began about 10Â Ma. These results indicated that Polystichum probably originated in eastern Asia and migrated into Australasia: first into Australia and then into New Zealand.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Palaeontology
Authors
Chun-Xiang Li, Shu-Gang Lu, Qun Yang,