Phylogenetic study of the New Caledonian endemic genus Adenodaphne (Lauraceae) confirms its synonymy with Litsea

The genus Adenodaphne is currently considered endemic to New Caledonia, but its distinction from Litsea is questionable based on morphological similarity. An earlier phylogenetic analysis (ITS) including one species of Adenodaphne and two Asian species of Litsea did support their close relationship but did not permit resolution of their generic boundary. We sampled the four species of Adenodaphne currently recognized (11 accessions) and 11 of the 13 endemic species of Litsea currently recognized, plus one undescribed species (24 accessions in total). Based on our extensive herbarium studies, fieldwork, and especially our molecular phylogenetic analyses (ITS), we conclude that Adenodaphne is not distinct from Litsea and that all species of Adenodaphne should be recognized within Litsea, thereby necessitating the creation of two new species synonymies and one nomen novum. In addition, Litsea paoueensis is here synonymized with L. deplanchei. Finally, our phylogenetic analysis suggests that the sole species of Litsea from New Zealand, which is endemic, results from a rarely documented long-distance dispersal event from New Caledonia.

Automated summary

In this study, the distinction between Adenodaphne and Litsea, two genera endemic to New Caledonia, is questioned based on morphological similarity. Through extensive research, including molecular analysis and examination of specimens, it is concluded that Adenodaphne should be recognized within Litsea. Moreover, the phylogenetic analysis suggests a rare long-distance dispersal event from New Caledonia to New Zealand in the evolution of the endemic Litsea species.