Molecular divergence between Treubia Goebel and Apotreubia S. Hatt. & Mizut., the two genera of the archaic liverwort class Treubiopsida (Hepaticophytina): Studies in austral temperate rain forest bryophytes 19
Stech, Michael; Konstantinova, Nadezhda A.; Frey, Wolfgang
Molecular relationships of Treubia and Apotreubia, the two genera of the archaic liverwort class Treubiopsida, are evaluated by a comparison of trnLUAA intron sequences of three species of Treubia (Treubia lacunosa and T. spec. from New Zealand, T. scapanioides from Chile), and Apotreubia hortonae. Trees generated by maximum parsimony, maximum likelihood and neighbor joining analyses of partial trnLUAA intron sequences of the Treubiaceae and 22 other bryophytes support the class Treubiopsida within the monophyletic Hepaticophytina, as Treubia and Apotreubia form a clade with high bootstrap support separated from the representatives of Marchantiopsida, Jungermanniopsida, and Blasiopsida. Low length and sequence divergence is observed in Treubia, with only 9-14 substitutions differentiating between the Chilean T. scapanioides and the New Zealand Treubia species in the complete trnLUAA intron, whereas considerable length differences and up to approximately 40 substitutions (depending on the alignment) are observed between Treubia and Apotreubia hortonae. The clear molecular distinction of Treubia and Apotreubia is in accordance with their morphological differences and supports their recognition as separate genera. In addition, the results do not support an intermediate position of Treubia scapanioides between the genera Treubia and Apotreubia as previously proposed.