Re-Evaluation of the Taxonomic Status of Campylopus longigemmatus (Leucobryaceae, Bryophyta)

Campylopus longigemmatus was initially described from a specimen collected in Xizang (Tibet), China. Later, this species was transferred to Dicranodontium as D. longigemmatum, and then synonymized with D. didymodon and D. denudatum. However, the protologues of C. longigemmatus and D. denudatum are clearly different, and the morphological traits of C. longigemmatus suggest it belongs to Campylopodiella. To address this issue, we conducted molecular-phylogenetic analyses based on four molecular markers (ITS, nad5, trnS-TrnF, and atpB-rbcL). Campylopus longigemmatus formed a maximally supported clade with the American species Campylopodiella flagellacea. As there are no distinct morphological differences between Campylopus longigemmatus and Campylopodiella flagellacea, the previously proposed synonymy of Campylopus longigemmatus with Dicranodontium denudatum is rejected, and Campylopus longigemmatus is proposed as a new synonym of Campylopodiella flagellacea. This implies the first record of Campylopodiella flagellacea from China and Asia.