A morphometric and molecular study in Tortula subulata complex (Pottiaceae, Bryophyta)

Abstract

Specimens belonging to Tortula subulata complex (T. inermis, T. mucronifolia and T. subulata) were analysed using a combination of morphometric methods based on quantitative characters [principal component analysis (PCA), discriminant analysis (DA); 76 samples)] and molecular methods (ITS1 – 5.8S rRNA gene and ITS2; 47 samples) to assess patterns of morphological and molecular differentiation within this complex of taxa. The study shows that four species can be recognized: T. mucronifolia, T. subulata, T. inermis and T. subulata var. angustata with bistratose border, which is elevated to the species rank as T. schimperi nom. nov. The most valuable quantitative characters for identification of these species are the strata number of the marginal laminal cells, the ratio of middle marginal laminal cell width/middle marginal laminal cell length, basal membrane of peristome length, middle laminal cell width and papillae number on the middle laminal cells. The internal transcribed spacer (ITS) data suggest that this group of taxa is not monophyletic, T. mucronifolia being close to Protobryum bryoides (=Tortula protobryoides). The remaining species seem to be a monophyletic group, T. schimperi being the sister group of the clade composed by T. inermis and T. subulata. T. subulata is considered to be of high morphological variability, for which ITS sequences did not resolve the internal relationships.

bryophytes, ITS sequence, molecular systematics, taxonomy