The nuclear
ITS1-5.8S-ITS2 DNA region is studied for 29 specimens of Coscinodon from
Eurasia, mostly from Russia, and 4 specimens from North America. The sequences
were found to be much less variable than in two other genera of the
Grimmiaceae, Grimmia and Schistidium. Coscinodon yukonensis Hastings
was found to be rather widespread in Asia, despite never having been
reported before in this continent, being erroneously treated as C. humilis Milde.
European C. humilis is quite distinct molecularly from Asian C.
yukonensis and forms a sister clade to C. cribrosus (Hedw.) Spruce.
Some Asian populations of "C. cribrosus" were unresolved,
being found outside the main clade formed by C. cribrosus and C.
humilis. Coscinodon hartzii C.E.O. Jensen forms a basal grade
to the rest of the species in the genus. Coscinodon pseudohartzii is
described as a species new to science from Siberia.