Cleaning a taxonomic dustbin: placing the European Hypnum species in a phylogenetic context!

Abstract

The pleurocarpous moss genus Hypnum s.l. is a species-rich (> 40 species) cosmopolitan genus, of which 21 taxa occur in Europe. Although several of these species show high morphological resemblance there are strong indications that the genus is highly paraphyletic, which may be masked by convergent morphological evolution. Using molecular information, we analyse whether the morphological similarity of gametophytes of the European Hypnum taxa is explained by common ancestry or convergence. We provide a phylogenetic reconstruction of the relationships of the currently recognized European Hypnum taxa in a broad pleurocarpous moss context (192 taxa) using the nuclear ITS1-5.8S-ITS2, the plastid rps4 gene and trnL-F, and the mitochondrial nad5 intron. Bayesian tree topologies show that the genus is polyphyletic, and we retain only the Hypnum cupressiforme complex within Hypnum. The genus originally represented half of the moss species diversity, as it accommodated basically all pleurocarpous mosses; here we retain only seven species and one variety. The remainder of the species where resolved either within the three families Amblystegiaceae, Entodontaceae, and Pylaisiaceae, or in an independent clade that we describe as the new family Stereodontaceae. The Stereodontaceae includes five European species, all in the genus Stereodon, where they were already placed in the 18th century. In addition, we describe the four new genera Aquilonium, Insomniella, Jochenia, and Lignocariosa, and make new combinations for several Hypnum species.

On the taxonomy of Anomodontaceae and Heterocladium (Bryophyta)

“…Many of them have been widely used because they look conspicuous and are easily observed. The molecular phylogenetic approach to taxonomy has already revealed many cases where morphological characters have been overvalued, overturning assumptions about the importance of, for example, the "Isobryalean peristome" (Buck et al, 2000;Tsubota et al, 2002), Neckera-like undulate leaves (Olsson et al, 2011), Drepanocladus-like falcatesecund leaves with a costa (Vanderpoorten et al, 2002); Hypnum-like falcate-secund leaves without a costa (Gardiner et al, 2005;Arikava et al, 2008;Câmara et al, 2018;Schlesak et al, 2018), and a dendroid growth-form (Ignatov et al, 2014). In this paper we will try to address one more such character, the papillosity of the laminal cells.…”

Could Bryophagous Beetles (Coleoptera: Byrrhidae) Help Us Understand Bryophyte Taxonomy? Preferences within the Hypnum cupressiforme Hedw. Species Complex

“…[ 19 , 20 ]. Within the entire Hypnum genus which is sometimes considered highly polyphyletic, the H. cupressiforme forms quite a compact clade [ 21 , 22 ].…”

Morphological characterization of Hypnaceae (Bryopsida, Hypnales): Investigating four genera from Western Himalayas by using LM and SEM techniques

“…basically originates from the word “Hypnos” which means sleep, possibly when some of the pleurocarpous mosses were used as filling of mattresses and pillows. The studies conducted by Bruch, Schimper and Gumbel in 1851 and Fleischer's studies from 1906 to 1908 and 1915 to 1923 resulted in the development of the family Hypnaceae (Bruch et al, ; Fleischer, ; Fleischer, ; Schlesak, Hedenäs, Nebel, & Quandt, ). Schimper in 1856, mainly established the family Hypnaceae and with the passage of time some characteristic members have been separated from the family and classified into some new families.…”

“…The detailed molecular phylogenetic studies resolved many taxonomic problems in various pleurocarpous families. But as far as Hypnaceae or Hypnum is concerned, the studies are inadequate to provide a valid taxonomic treatment, however, these studies suggested the paraphyletic nature of the family Hypnaceae (Schlesak et al, ).…”

“…The genus was initially composed by Linnaeus, when he included nearly all branched and creeping pleurocarpous mosses in the genus. It is a large genus having almost 60 species which are distributed around the whole world (Ignatov et al, ; Schlesak et al, ).…”