A multilocus phylogeny of the moss genus Didymodon and allied genera (Pottiaceae): Generic delimitations and their implications for systematics

Abstract

Didymodon s.l. is one of the largest genera in the moss family Pottiaceae, with about 122 species distributed in all continents. This, together with its high degree of morphological variation, has made it one of the taxonomically most challenging genera of Pottiaceae. Circumscription of Didymodon s.l. has been, and still is, controversial. To date, the only molecular study that has investigated the delimitation of the genus has been far from comprehensive (35 samples from 27 species), limited in geographical scope (mainly restricted to Europe), and based exclusively on ITS sequences. To evaluate the circumscription of Didymodon s.l. and its relationships with the allied genera Andinella, Gertrudiella, and Tridontium, we conducted phylogenetic analyses of DNA sequences for three plastid markers (atpB-rbcL, trnG, and trnL-F) and one nuclear locus (ITS) for 335 samples representing 86 species of Didymodon s.l. (ca. 70%), and all taxa of the genera Andinella, Gertrudiella, and Tridontium. Individual markers and concatenated matrices were analyzed using maximum likelihood and Bayesian approaches. Our results indicate that Didymodon s.l. is not monophyletic, because Andinella, Gertrudiella, and Tridontium species are nested within it. Species of these four genera can be divided into eight well-supported and morphologically distinct genera: Didymodon s.s., Geheebia, Gertrudiella, Husnotiella, Trichostomopsis, Tridontium, Vinealobryum, and Zanderella. In correspondence with the results presented, 38 new combinations, 10 new synonyms, and a new name are provided for those taxa where required, and lectotypes are designated for 13 names. A diagnostic key to the eight recognized genera is provided.

Didymodon sinicus (Pottiaceae, Musci), a new species from China and its phylogenetic position based on molecular data

“…Recently, D. obtusus was synonymized with D. stewartii (E.B. Bartram) R.H. Zander (Jiménez et al 2021), but this result is very suspicious because no specimen of D. stewartii was tested in their molecular systematics research and thus there is no comparison between the two species.…”

Circumscription and Phylogenetic Position of Two Propagulose Species of Syntrichia (Pottiaceae, Bryophyta) Reveals Minor Realignments within the Tribe Syntricheae

“…(2), S. erythrodontus (Taylor) Wilson ex Mitt. (3) and Willia brachychaete (Dusén) R.H. Zander (2); also, we selected some more distantly related Pottiaceae members according to Cano et al [ 6 ] and Jiménez et al [ 29 ], including four representative Pottieae sensu Zander [ 1 ]: Bryoerythrophyllum recurvirostrum (Hedw.) P.C.…”

“…The ITS1 and ITS2 were either amplified and sequenced separately or in a single amplification. These loci have been shown to be useful for phylogenetic reconstruction in the Pottiaceae [ 6 , 14 , 29 , 32 ]. The primer pairs used for each locus were trn G-F/ trn G-R [ 33 ], trn C/ trn F [ 34 ], ITS5-bryo/ITS4-bryo [ 35 ], ITS1-F/ITS1-R [ 36 ], and seqITS2 [ 37 ].…”

“…To understand the position of S. amphidiacea and S. gemmascens in relation to other members of the genus, we included 1-4 specimens of: Syntrichia amphidiacea (3), S. angustifolia (Herzog) M.J. Cano (3) and Willia brachychaete (Dusén) R.H. Zander (2); also, we selected some more distantly related Pottiaceae members according to Cano et al [6] and Jiménez et al [29], including four representative Pottieae sensu Zander [1]: Bryoerythrophyllum recurvirostrum (Hedw.) P.C.…”

A molecular approach to the phylogeny of the moss genus Pseudocrossidium (Pottiaceae, Bryopsida) and its taxonomic implications

“…Jiménez & M.J. Cano (Jiménez et al, 2012; Jiménez & Cano, 2020), recently considered as a synonym of Gertrudiella Broth. (Jiménez et al, 2021), two taxa have been elevated or considered again at the rank of species (Eckel et al, 1997; Zander, 2007; Jiménez et al, 2009), three species have been resurrected from synonymy (Cano et al, 2016), and two have been newly described (Cano et al, 2011, 2015). Therefore, currently, 21 species are recognized in Pseudocrossidium .…”