Browsing by Author "Vanderpoorten, A."
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- Circumscription, classification, and taxonomy of Amblystegiaceae (Bryopsida) inferred from nuclear and chloroplast DNA sequence data and morphologyPublication . Vanderpoorten, A.; Hedenäs, Lars; Cox, C. J.; Shaw, A. J.Results from a previous broad-scale analysis employing trnL-trnF sequence data for 168 Hypnalean and 11 Hookerialean taxa, and an analysis employing two chloroplast regions, trnL-trnF and atpB-rbcL, one nuclear region, the internal transcribed spacers of 18S-26S rDNA, plus 68 morphological characters for a reduced data set of 54 Hypnalean taxa, were used to circumscribe Amblystegiaceae. The analyses provided two well-supported main clades including taxa traditionally included in Amblystegiaceae s.l. and recognized as Amblystegiaceae s.str. [Anacamptodon, Amblystegium, Campyliadelphus, Campylium, Cratoneuron, Cratoneuropsis, Drepanocladus s.str., Gradsteinia, Hygrohypnum s.str. (including the type species, H. luridum, but excluding a number of other species previously accommodated in the genus), Hypnobartlettia, Leptodictyum, Palustriella, Pseudo-calliergon, and Serpoleskea] and Calliergonaceae stat. nov. (Calliergon, Hamatocaulis, Loeskypnum, Straminergon, and Warnstorfia). Scorpidium and "Hygrohypnum" ochraceum were closely related to Calliergonaceae but were not included in the family because of the lack of support. All these genera but Anacamptodon have previously been included in Amblystegiaceae s.l. The sporophytic features of Anacamptodon, which contrast with those of all the other members of Amblystegiaceae, are interpreted as adaptations to an epiphytic habitat and suggest, together with other recent taxonomic works in Hookeriales, that characters related to sporophytic specializations are among the most homoplastic. Several other taxa (Calliergonella, Campylophyllum, Conardia, Donrichardsia, "Hygrohypnum" smithii, Platydictya, Sanionia), previously included in Amblystegiaceae s.l., appeared more closely related to other Hypnalean families. Recircumscribed Amblystegiaceae, and several clades within the family, have no identifiable morphological synapomorphies. A new system of classification for recircumscribed Amblystegiaceae, including morphological delimitation of presented clades based on maximum likelihood reconstruction of ancestral character states, is proposed and appropriate nomenclatural changes made.
- Disentangling knots of rapid evolution: origin and diversification of the moss order HypnalesPublication . Huttunen, S.; Bell, N.; Bobrova, V. K.; Buchbender, V.; Buck, W. R.; Cox, C. J.; Goffinet, B.; Hedenäs, Lars; Ho, B. -C.; Ignatov, M. S.; Krug, M.; Kuznetsova, O.; Milyutina, I. A.; Newton, Alice; Olsson, S.; Pokorny, L.; Shaw, J. A.; Stech, M.; Troitsky, A.; Vanderpoorten, A.; Quandt, D.The Hypnales are the largest order of mosses comprising approximately 4200 species. Phylogenetic reconstruction within the group has proven to be difficult due to rapid radiation at an early stage of evolution and, consequently, relationships among clades have remained poorly resolved. We compiled data from four sequence regions, namely, nuclear ITS1–5.8S–ITS2, plastid trnL–F and rps4, and mitochondrial nad5, for 122 hypnalean species and 34 species from closely related groups. Tree topologies from both Bayesian and parsimony analyses resolve the order as monophyletic. Although inferences were made from fastevolving genes, and despite strong phylogenetic signal in the nuclear ITS1–5.8S–ITS2 data, monophyly, as well as backbone nodes within the Hypnales, remains rather poorly supported except under Bayesian inferences. Ancestral distribution based on Bayesian dispersal-vicariance analysis supports a Gondwanan origin of the Hypnales and subsequent geographical radiation in the area of the former Laurasian supercontinent. Reconstruction of historical biogeography is congruent with mainly tropical and Gondwanan distributions in the sister groups Hypnodendrales, Ptychomniales, and Hookeriales, and with the dating for the oldest pleurocarp and hypnalean fossils. We contrast groupings in the phylogenetic tree with recent classifications and other phylogenetic inferences based on molecular data, and summarise current knowledge on the evolutionary history of, and relationships among, the Hypnales.
- Erratum: circumscription, classification, and taxonomy of the Amblystegiaceae (Bryopsida) inferred from nuclear and chloroplast DNA sequence data and morphologyPublication . Vanderpoorten, A.; Hedenäs, Lars; Cox, C. J.; Shaw, A. J.
- Evolution of multiple paralogous adenosine kinase genes in the moss genus Hygroamblystegium: phylogenetic implicationsPublication . Vanderpoorten, A.; Shaw, A. J.; Cox, C. J.Maximum likelihood analyses of DNA sequences from two chloroplast regions, trnL–trnF and atpB–rbcL, and the internal transcribed spacers of 18S–5.8S–26S rRNA gene array, were performed to resolve species relationships within the moss genus Hygroamblystegium. Constraining morphospecies to monophyly resulted in significantly less likely trees for H. tenax, but not for the other species. The lack of support for most clades and the partial incongruence among topologies necessitated the use of another independent, more variable region, namely the adenosine kinase gene (adk). Sequences for adk were polymorphic but were present as multiple copies within individuals, making parology a problem for phylogenetic analyses. Adk evolution was reconstructed using a reconciled gene tree approach in which duplications and losses were minimized in the context of an estimate of the species tree derived from the analysis of the cp and nrDNA sequence data. Additional resolution of the species tree was then obtained by searching for reconstructions that further reduced adk duplications and losses. All the traditionally recognized morphospecies appeared to be polyphyletic in the resulting tree. Together with previous data from different molecular markers, the results support the interpretation that Hygroamblystegium represents a recent radiation in which molecular and morphological evolution have been uncoupled.
- Extant diversity of bryophytes emerged from successive post-Mesozoic diversification burstsPublication . Laenen, B.; Shaw, B.; Schneider, H.; Goffinet, B.; Paradis, E.; Desamore, A.; Heinrichs, J.; Villarreal, J. C.; Gradstein, S. R.; McDaniel, S. F.; Long, D. G.; Forrest, L. L.; Hollingsworth, M. L.; Crandall-Stotler, B.; Davis, E. C.; Engel, J.; Von Konrat, M.; Cooper, E. D.; Patino, J.; Cox, C. J.; Vanderpoorten, A.; Shaw, A. J.Unraveling the macroevolutionary history of bryophytes, which arose soon after the origin of land plants but exhibit substantially lower species richness than the more recently derived angiosperms, has been challenged by the scarce fossil record. Here we demonstrate that overall estimates of net species diversification are approximately half those reported in ferns and similar to 30% those described for angiosperms. Nevertheless, statistical rate analyses on time-calibrated large-scale phylogenies reveal that mosses and liverworts underwent bursts of diversification since the mid-Mesozoic. The diversification rates further increase in specific lineages towards the Cenozoic to reach, in the most recently derived lineages, values that are comparable to those reported in angiosperms. This suggests that low diversification rates do not fully account for current patterns of bryophyte species richness, and we hypothesize that, as in gymnosperms, the low extant bryophyte species richness also results from massive extinctions.
- Phylogeny and morphological evolution of the Amblystegiaceae (Bryopsida)Publication . Vanderpoorten, A.; Hedenäs, Lars; Cox, C. J.; Shaw, A. J.To circumscribe the moss family Amblystegiaceae, we performed a broad-scale analysis of trnL–trnF spacer sequence data for 168 species of the Hypnales and 11 species of the Hookeriales and additional analyses of trnL–trnF and atpB–rbcL (chloroplast DNA), one nuclear region, the internal transcribed spacers of 18S–26S rDNA, and 68 morphological characters for a reduced data set of 54 species of Hypnales. The traditionally circumscribed Amblystegiaceae are polyphyletic and include the Amblystegiaceae s. str. and the Calliergonaceae fam. nov., plus several taxa closely related to other Hypnalean families. Generic relationships within the redefined Amblystegiaceae were investigated by analyzing data from the three DNA regions and morphology as used in the broader analysis. Reconstruction of morphological evolution was evaluated using maximum- parsimony and maximum-likelihood. Numerous independent character-state transitions implied by the phylogeny suggest that morphological characters that have traditionally been used to delineate the Amblystegiaceae are homoplastic. Sporophytic traits, which are generally given primacy over gametophytic traits in moss classification, are more labile than previously thought, and many characters that are related to sporophyte specializations are strongly correlated with habitat conditions. The evolution of several gametophyte features previously thought to be reliable for delineating the family are also strongly correlated with habitat. These observations help to explain the instability of the Amblystegiaceae in previous taxonomic and phylogenetic analyses based on morphology.
- A taxonomic reassessment of the Vittiaceae (Hypnales, Bryopsida): Evidence from phylogenetic analyses of combined chloroplast and nuclear sequence dataPublication . Vanderpoorten, A.; Goffinet, B.; Hedenäs, Lars; Cox, C. J.; Shaw, A. J.The Vittiaceae are a small family of aquatic mosses that are defined based on gametophytic traits whose interpretation has led to conflicting taxonomic arrangements. Phylogenetic analyses of two cpDNA regions, trnL-trnF and atpB-rbcL, indicate that Vittia is nested within the Amblystegiaceae s. str., suggesting that the family Vittiaceae should not be recognized. Platylomella lescurii appears nested within the Thuidiaceae/Leskeaceae. This suggests that the series of character states shared by Vittia and Platylomella, including a differentiated leaf border, short laminal cells, stiff stems, and a thick costa, are convergent features that arose independently in unrelated lineages of aquatic Hypnales. Within the Amblystegiaceae, phylogenetic analyses of the two cpDNA regions combined with ITS sequence data show that Hypnobartlettia, Vittia elimbata spec. nov., V. pachyloma, and V. salina, despite their strong morphological similarity to aquatic Amblystegium species, form a clade that is sister to the Drepanocladus/Pseudocalliergon complex. This combined clade is unresolved at a polytomy that includes Amblystegium serpens and a clade including all the other Amblystegium species. The occurrence of A. serpens outside the strongly supported clade including other Amblystegium species suggests that A. serpens may be better accommodated in a distinct genus. Amblystegium serpens is the type species of Amblystegium and thus retains the name. The other species are accommodated in their own genus, Hygroamblystegium, including H. fluviatile, H. humile comb. nov., H. noterophyllum, H. tenax, and H. varium.