Phylogenetic relationships of Eurya (Pentaphylacaceae) with a focus on Japanese species

Ohi-Toma, Oguri E, Abe H, Kato H, Aamano M, Su M-H, Kong H, Nagamasu H, Naiki A

The phylogenetic relationships among Japanese species of Eurya (Pentaphylacaceae) were investigated using sequences of the internal transcribed spacer (ITS) and the external transcribed spacer (ETS) regions of nuclear ribosomal DNA, with reference to a previous study focused on Taiwanese species. The maximum likelihood phylogenetic tree revealed that the Japanese species were divided into two lineages (Clades A and B), with several unexpected close relationships among them. In Clade A, E. yakushimensis and E. zigzag formed a distinct subclade consisting of only these two species, while E. osimensis formed a solitary subclade with a long branch length. Eurya boninensis and E. yaeyamensis were placed in a subclade of Clade A along with species from Taiwan, the Philippines, and Vanuatu. Notably, E. boninensis from Chichi-jima Island was found to be more closely related to E. yaeyamensis than to E. boninensis from Haha-jima Island. In Clade B, E. japonica is monophyletic, while E. emarginata and E. sakishimensis were not. Regarding the varieties of E. emarginata, var.
minutissima is likely to be treated as a distinct species, but the genetic distinction of var. ryukyuensis remains unclear. Eurya sakishimensis was genetically indistinguishable from E. emarginata in the southern Ryukyu Islands and some Taiwanese species. Furthermore, E. hayatae in Taiwan is distinct from E. nitida. The former appears to include an undescribed species.

Journal of Japanese Botany

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