Anomodontella Ignatov & Fedosov, 2019

Anomodontella Ignatov & Fedosov View in CoL , gen. nov.

Type species: Anomodontella longifolia (Schleich. ex Brid.) Ignatov & Fedosov , comb. nov. – Basionym: Pterigynandrum longifolium Schleich. ex Brid., Muscol. Recent. Suppl. 4: 128. 1819 [1818]. Monospecific genus.

Etymology: deminutive of Anomodon .

Diagnosis: Anomodontella differs from other Anomodontaceae in: laminal cells unipapillose on both surfaces, with papillae on the ventral surface more prominent than on the dorsal, and from all other pleurocarps in the paired, “geminate” arrangement of the papillae; compound proximal branch leaves (occurring in Anomodontaceae only in A. rugelii ); long acuminate leaves; smooth and elongate cells in perichaetial leaves; exostome teeth striolate on outer surface in proximal half and highly papillose distally.

Additional differentiating features of Anomodontella are the very loose tufts composed of numerous attenuate, flagelliform branches (similar in habit to Heterocladium ), and the dark to yellow-green color of the plants, not glaucous as in most Anomodon and Haplohymenium species. Such a color is not unique in the Anomodontaceae , occurring e.g. in Haplohymenium flagellare and H. longinerve .

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The species closer to A. viticulosus than Anomodontella longifolia from three groups: (1) Anomodon s. str. ( A. viticulosus , A. minor , A. thraustus ); (2) Haplohymenium species; and (3) the monospecific clade of Anomodon rugelii (or, in some trees forming a clade with A. longifolius ). One of the possible taxonomic solutions is to lump all the species in the genus Anomodon , following Granzow-de la Cerda (1997). At the same time, the acceptance of Haplohymenium at generic level seems to us reasonable: these much smaller plants with papillose and hairy calyptrae are well delimited and form a highly supported clade in most analyses. This unity is somewhat surprising, as Haplohymenium includes plants highly polymorphic in papillae structure (representing essentially most types known in Anomodon in its new circumscription).

The acceptance of Haplohymenium however implies the necessity of separating Anomodon rugelii . In most trees it keeps a position sister to the clade of Anomodon s. str. + Haplohymenium ( Figs. 1 View Fig , 2 View Fig , 4 View Fig ) or forms a clade with Anomodontella ( Fig. 6 View Fig ).

Iwatsuki (1963) suggested its segregation in a separate section, i.e. at the same level as Anomodontella . The phylogenetic analysis by Granzow-de la Cerda (1997) did not find sufficient morphological distinction in A. rugelii , although the author acknowledged its unique auriculate leaf base ( Fig. 11 View Fig ), the compound proximal branch leaves (“pseudoparaphyllia present” in his terminology), and the golden to rusty color of the costa.

Additional characters distinguishing A. rugelii from the core Anomodon species include narrow peristome teeth, with the plates markedly narrower than the trabeculae and papillose on both surfaces, and also the apiculate leaf apex. The latter character is not present in every leaf, and Granzow-de la Cerda (1997) wrote that it is unreliable, although even its occasional presence is important, as it never occurs in Anomodon s. str. However, an apiculus occurs in Haplohymenium , being especially conspicuous in H. triste , although similarly not in every leaf and every shoot.

Therefore we segregate A. rugelii in its own monospecific genus.