Two new genera of Sapindaceae (Cupanieae) from the southern Pacific: Lepidocupania and Neoarytera

Phylogenetic analyses of the family Sapindaceae inferred from nuclear and plastid sequence data have revealed a high level of para- and polyphyly at the subfamilial, tribal, and generic levels. A phylogenetic study focusing on taxa in the southern Pacific belonging to tribe Cupanieae has shown that the two most species-rich genera, Arytera Blume and Cupaniopsis Radlk., are polyphyletic. This study aims to clarify generic limits among the taxa currently placed in these two genera by identifying morphological features that support monophyletic groups suitable for recognition at the generic level. Specimens deposited in major herbaria holding material of these taxa were examined to complement extensive field observations. Careful consideration of morphological features in light of previous taxonomic treatments and the results of phylogenetic analyses enabled us to propose a re-aligned generic framework for Cupanieae in which two new genera are described to accommodate species previously placed in Arytera and Cupaniopsis: viz., Lepidocupania Buerki, Callm., Munzinger & Lowry (21 species) and Neoarytera Callm., Buerki, Munzinger & Lowry (4 species). A total of 25 new combinations are made, lectotypes are designated for nine names (two first step and seven second-step), and one new synonym is established. A key to the newly circumscribed genera Arytera and Cupaniopsis, along with allied genera, is provided, accompanied by information on the distribution and ecology of each species.