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Newly resolved relationships in an early land plant lineage: Bryophyta class Sphagnopsida (peat mosses)
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Orientador(es)
Resumo(s)
Premise of the study : The Sphagnopsida, an early-diverging lineage of mosses (phylum Bryophyta), are morphologically and
ecologically unique and have profound impacts on global climate. The Sphagnopsida are currently classifi ed in two genera,
Sphagnum (peat mosses) with some 350 – 500 species and Ambuchanania with one species. An analysis of phylogenetic relationships among species and genera in the Sphagnopsida were conducted to resolve major lineages and relationships among species within the Sphagnopsida. Methods : Phylogenetic analyses of nucleotide sequences from the nuclear, plastid, and mitochondrial genomes (11 704 nucleotides total) were conducted and analyzed using maximum likelihood and Bayesian inference employing seven different
substitution models of varying complexity.
Key results : Phylogenetic analyses resolved three lineages within the Sphagnopsida: (1) Sphagnum sericeum , (2) S. inretortum plus Ambuchanania leucobryoides , and (3) all remaining species of Sphagnum . Sister group relationships among these three clades could not be resolved, but the phylogenetic results indicate that the highly divergent morphology of A. leucobryoides is derived within the Sphagnopsida rather than plesiomorphic. A new classifi cation is proposed for class Sphagnopsida, with one order (Sphagnales), three families, and four genera.
Conclusions : The Sphagnopsida are an old lineage within the phylum Bryophyta, but the extant species of Sphagnum represent a relatively recent radiation. It is likely that additional species critical to understanding the evolution of peat mosses await discovery, especially in the southern hemisphere.
Descrição
Palavras-chave
Ambuchanania Bryophyte phylogeny Land plant phylogeny Peat mosses Sphagnopsida Sphagnum
Contexto Educativo
Citação
Shaw, A.J.; Cox, C.J.; Buck, W.R.; Devos, N.; Buchanan, A.M.; Cave, L.; Seppelt, R.; Shaw, B.; Larraín, J.; Andrus, R.; Greilhuber, J.; Temsch, E.M. Newly resolved relationships in an early land plant lineage: Bryophyta class Sphagnopsida (peat mosses), American Journal of Botany, 97, 9, 1511-15, 2010.
Editora
Botanical Society of America: AJB