Arctoa (2019) 28: 75–104
A molecular phylogenetic analysis based on nuclear ITS, plastid trnS-F, rpl16, atpB–rbcL and mitochondrial nad5 revealed polyphyly in the genus Anomodon, and therefore its segregation into four genera is proposed. The largest clade includes A. viticulosus, the generitype of Anomodon, and all species with a broadly rounded leaf apex, including those with both pluripapillose (A. minor, A. thraustus, A. dentatus) and pseudounipapillose (A. abbreviatus, A. solovjovii) laminal cells. The species of Haplohymenium form a sister clade to Anomodon; however this clade is always maximally supported in Bayesian analyses, and thus Haplohymenium merits taxonomic recognition as a genus of its own. Two closely related species, Anomodon attenuatus and A. giraldii, were found deeply nested in the Neckeraceae, and thus they are segregated in the genus Pseudanomodon (Limpr.) Ignatov & Fedosov. Anomodon rugelii was found to be distant from the core Anomodon clade and is segregated into a new genus Anomodontopsis Ignatov & Fedosov within the Anomodontaceae. Anomodon longifolius has an erratic position in various analyses, appearing basal in the Anomodontaceae clade or sister to the A. rugelii clade in the organellar trees, or in a clade with Heterocladium dimorphum, closer to the Neckeraceae than to the Anomodontaceae, in the tree inferred from nuclear ITS. It is therefore referred to the new genus Anomodontella Ignatov & Fedosov in the Anomodontaceae. Likewise, Heterocladium species form two clades, centered around H. dimorphum and H. heteropterum. The latter group is referred to Lembophyllaceae, while H. dimorphum and related species form a fairly isolated group and are segregated in their own genus Heterocladiella Ignatov & Fedosov in the monogeneric family Heterocladiellaceae Ignatov & Fedosov. The genus Herpetineuron is excluded from the Anomodontaceae.