A taxonomic revision of Herbertus (Jungermanniidae: Herbertaceae) in the Neotropics based on nuclear and chloroplast DNA and morphology

Abstract

A revision of Neotropical Herbertus leads to the recognition of two species (H. sendtneri, H. juniperoideus), the latter with four subspecies (H. juniperoideus ssp. juniperoideus, ssp. acanthelius, ssp. bivitattus, ssp. pensilis). A key to the taxa, morphological descriptions, specimen lists, and extensive synonymy are provided. Maximum likelihood and parsimony analyses of nuclear ribosomal internal transcribed spacer (nrITS) and chloroplast (cp) trnL-trnF sequences result in well-resolved topologies with H. sendtneri placed sister to a clade with Asian, Holarctic, and African species. H. juniperoideus constitutes a separate clade made up of polyphyletic H. juniperoideus ssp. acanthelius and ssp. pensilis, monophyletic H. juniperoideus ssp. bivitattus, and several accessions that could be identified to species level only. It is unclear whether the H. juniperoideus topology reflects plasticity of a variable species, occasional hybridization between morphologically clearly distinct populations or cryptic speciation.