Fedosov, V.E., A.V. Fedorova, E.A. Ignatova & M.S.
Ignatov. 2024. On the genus Pterygoneurum (Pottiaceae,
Bryophyta) in
Arctoa (2025) 34: 31–43
doi: 10.15298/arctoa.34.03
A partial taxonomic study of the genus Pterygoneurum
with the focus on the Russian plants previously referred to P. lamellatum
is conducted. In addition to morphological study, it includes a molecular
phylogenetis analysis of the plastid rps4 and trnMV sequence
data, which found in the genus three supported clades. The first one includes P.
ovatum and Central European plants of P. lamellatum, the second is
formed by European endemics P. papillosum and P. sampaianum, and
the third includes P. subsessile, cleistocarpous P. kozlovii and P.
sibiricum, and Russian plants referred to P. lamellatum, from two
regions: the North Asia and the SE European Russia, the Caspian Lowland, which
have distinct morphology. We suggest resurrecting the name P. arcticum
for the ‘North Asian P. lamellatum’, which differs from the European P.
lamellatum by the low lamellae that lack lateral outgrowths, and costa
excurrent into a short awn. The second group of the ‘Russian P. lamellatum’,
from the Caspian Lowland, is described as a new species, P. volgense. It
has some characters common with a European P. lamellatum, i.e., recurved
to revolute leaf margins, excurrent costae, exserted cylindric capsules with
opercula possessing spiral cell rows, an occasional presence of peristome
remnants, and a moderately large spores, but differs from it in having forked
papillae on both leaf surfaces. Such morphology makes it distinct, though the
studied phylogenetic markers in this group are low variable, not separating P.
kozlovii, P. volgense, and one of the lineages of P. subsessile.
A putative hybridogeneous speciation in Pterygoneurum is discussed,
since some monophyletic groups in this genus include plants with a
contrastingly different morphology, having at the same time a similar
distribution.