Neckera and Thamnobryum (Neckeraceae, Bryopsida): Paraphyletic assemblages

Recent phylogenetic analyses indicated that the backbone phylogeny of the pleurocarpous moss family Neckeraceae falls into three distinct clades. Here the detailed composition and phylogenetic relationships of the two major clades (the Neckera clade and the Thamnobryum clade) are analysed. The phylogenetic analyses, based on sequence data from the plastid rpll6 intron and the rps4-trnT-trnL-trnF cluster as well as the nuclear ITS1 and 2, retained this tripartition and revealed a strong biogeographic pattern, especially inside the Neckera clade. In addition, several morphological characters that have been held as unique and characteristic to a certain group of mosses and therefore valuable in taxonomic classification, were shown to be highly homoplastic and subjected to convergent evolution. Consequently, the circumscriptions of Leptodon and Thamnobryum are amended, the new genera Exsertotheca, Echinodiopsis and Thamnomalia (each with two species), and Alleniella (with ten species) are formally described and several implied nomenclatural changes are proposed, including synonymisation ofAlsia with Neckera and Cryptoleptodon with Leptodon.