Phylogenetic inference and peristome evolution in haplolepideous mosses, focusing on Pseudoditrichaceae and Ditrichaceaes. l.

Abstract

Pseudoditrichum mirabile, the only species of Pseudoditrichaceae, has been known for a long time from a single collection from the Canadian Arctic. Its systematic position remained enigmatic due to similarity in gametophyte structure with Ditrichaceae, a family that has simple peristomes, whereas the peristome in Pseudoditrichum is double. Due to this difference, Pseudoditrichum was classified in either Funariales or Bryales. A recent discovery of this species in the Anabar Plateau in northern Siberia has allowed its phylogenetic position to be tested based on plastid rps4 and rbcL and mitochondrial nad5 sequences. The results of this research reject the earlier hypotheses. Instead, the molecular analysis resolves Pseudoditrichum in a clade with Chrysoblastella chilensis (formerly Ditrichaceae) in the haplolepideous lineage. The peristome of Pseudoditrichum is of a previously unknown type with a fully developed exostome and hyaline endostome elements opposite the exostome teeth, based not on the 4:2:4 peristomial formula, but on 4:2:3. Double peristomes of the same type, albeit rather strongly reduced, occur in Catoscopium, Chrysoblastella, Distichium and Ditrichum flexicaule. The polyphyly of Ditrichaceae is confirmed by molecular phylogenetic analysis, and Ditrichum flexicaule and D. gracile are segregated into the new genus Flexitrichum and family Flexitrichaceae. An independent status of the recently resurrected family Distichiaceae is supported, and segregation of Chrysoblastella and Saelania into new monospecific families is proposed.

Testing hypotheses on suprageneric relationships and morphological evolution in the Leucobryaceae (Bryophyta)

“…In line with earlier phylogenetic studies (Cox et al 2010;Fedosov et al 2015Fedosov et al , 2016Hedderson et al 2004;La Farge et al 2000, 2002Stech 2004;Tsubota et al 2003Tsubota et al , 2004, the analyses of the present dataset resolved three well-supported lineages within the Leucobryaceae: the dicranoid Campylopus clade, the dicranoid Dicranodontium clade and the leucobryoid clade. The latter is characterized by the leucobryoid costa as synapomorphic character (Fig.…”

“…Earlier phylogenetic analyses could not resolve the relationships between the three major Leucobryaceae clades (Hedderson et al 2004) or supported different sister group relationships: Campylopus clade and leucobryoid clade (Tsubota et al 2004), Campylopus clade and Dicranodon tium clade (one tree in Stech 2004) and, most frequently, Dicranodontium clade and leucobryoid clade (Cox et al 2010;Fedosov et al 2015Fedosov et al , 2016La Farge et al 2000, 2002Stech et al 2012;Tsubota et al 2003Tsubota et al , 2004and another tree in Stech 2004). Three studies (Cox et al 2010;La Farge et al 2002;Tsubota et al 2003Tsubota et al , 2004 recovered the latter topology with ≥ 70% bootstrap support or ≥ 0.95 Bayesian posterior probability.…”

“…The taxon sampling comprised 63 Leucobryaceae specimens (representing 11 out of 14 genera and 45 species) as well as Archidium alternifolium (Archidiaceae), Eustichia longi rostris (Eustichiaceae) and Micromitrium tenerum (Micromitriaceae) as outgroup representatives following earlier phylogenetic reconstructions (Fedosov et al 2016;Goffinet et al 2011;Stech et al 2012). Molecular markers from all three genomes were sequenced: mitochondrial (mt) nad5 G1 intron, chloroplast (cp) trnS-trnF region and atpB-rbcL spacer and nuclear (nr) ribosomal ITS1-5.8S-ITS2 (ITS) region.…”

On the Bryoxiphium norvegicum and B. japonicum (Bryoxiphiaceae, Bryopsida).

“…Bescherelle (1892) established a separate family for the genus, and the subsequent elevation of its rank to the order Bryoxiphiales was suggested by Crum & Anderson (1981). Molecular phylogenetic data support highly isolated position of Bryoxiphium within the basal paraphyletic grade of haplolepideous lineage (Goffinet et al, 2001;Cox et al, 2010;Stech et al, 2012;Fedosov et al, 2016); however, its taxonomy and systematic position at the species level remain insufficiently known.…”

On the systematic position of Discelium (Bryophyta)

“…These five families usually do not form a clade, but compose a paraphyletic grade or partly polytomy between Diphyscium and two major terminal moss clades, the Bryidae and Dicranidae (cf. Goffinet et al, 2001;Hedderson et al, 2004;Tsubota et al, 2004, Cox et al, 2010Ignatov et al, 2015;Fedosov et al, 2016 as a clade (Goffinet et al, 2001;Larraín;Cox et al, 2010). At the same time, Gigaspermales are always basal in the paraphyletic grade or in weakly supported clade, and the position of Timmia is varaible, being however invariably between Gigaspermales and terminal clades of Dicranidae and Bryidae (cf.…”