Molecular systematics and biogeography of the liverwort genus Tylimanthus (Acrobolbaceae) Studies in austral temperate rain forest bryophytes 33

Phylogenetic analyses based on chloroplast DNA trnL_UAA intron and trnL_UAA-trnF_GAA spacer sequences indicate that the three genera of Acrobolbaceae subfam. Acrobolboideae (Acrobolbus, Marsupidium, and Tylimanthus) are closely related and cannot be separated at the generic level. Tylimanthus sect. Anisodon (tropical-subtropical species) is supported as a monophyletic group within sect. Tylimanthus (subantarctic species). These data indicate a southern Gondwanan origin of Tylimanthus followed by subsequent extension of the distribution range to (sub-)tropical and high mountain regions of the Neotropics, Africa, and Macaronesia. Relationships between the investigated Australian/New Zealand and southern South American species are incompletely resolved. The specimens of the southern South American T. urvilleanus and T. kunkelii are divided into two or three clades, respectively, in the molecular trees. In T. urvilleanus, these clades correlate with the geographic location and ecology of the specimens. For the higher montane to subalpine specimens, the new species Tylimanthus andinopatagonicus is established to separate these specimens from T. urvilleanus s. str. in the subantarctic lowland Magallanian forest region. The two Macaronesian endemics, Tylimanthus azoricus and T. madeirensis, are resolved as closely related sister species and are separated from the included American and African species of sect. Anisodon in the molecular trees. Their putative origin, either from the Neotropics or from tropical Africa, remains ambiguous. The molecular data further confirm the first collection of T. ruwenzorensis from West Africa and indicate that this species may be conspecific with the neotropical T. laxus. In contrast, the only recent collection of T. anisodontus endemic to St. Helena turned out to belong to Adelanthus.