The Scandinavian Syntrichia ruralis complex (Musci, Pottiaceae): a chaos of diversification

This study focusses on the molecular and morphological variation among Scandinavian species within the Syntrichia ruralis complex (S. calcicola, S. norvegica, S. ruraliformis, S. ruralis) of the moss family Pottiaceae, plus the similar-looking S. princeps. Molecular variation was explored based on the internal transcribed spacer 1 (ITS1), and the plastid atpB-rbcL spacer and rpl16 G2 intron. The relationships of the S. ruralis complex taxa were evaluated by including twelve additional, morphologically defined Syntrichia species in the ingroup, including S. subpapillosissima that was here shown to occur in Scandinavia. The molecular evidence favours a wide circumscription of the S. ruralis complex, including the species around S. caninervis and some other ones but excluding S. princeps, and that these species are closely related. ITS1 paralogues were revealed in almost one-third of the samples, and for those cloned between 2 and 8 variants were found, including specimens with paralogues belonging to two (2 cases) or three (1) different species. Together with several cases of discrepancy between ITS1 and plastid relationships, this could suggest an exchange of genetic material between species and may explain the extensive and partly overlapping morphological variation among some of them. Syntrichia subpapillosissima and S. ruralis var. epilosa may represent special phenotypes within S. ruraliformis or S. ruralis, but studies of more material of these are required to decide their correct status.

Posted on 23 December, 2020 08:32 by optilete optilete


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