Phylogeny and classification of Nesobasis Selys, 1891 and Vanuatubasis Ober & Staniczek, 2009 (Odonata: Coenagrionidae)
Island archipelagos in the South Pacific have relatively high species endemism within the insect order Odonata, specifically damselflies. Nesobasis Selys, 1891, an endemic damselfly genus from Fiji, includes over 20 species, but a clear understanding of its evolutionary relationship to other damselflies in the region is lacking. Scientists have questioned the monophyly of Nesobasis due to variations within the genus leading to the establishment of three divisions provisionally named as: comosa-, erythrops- and longistyla- groups. However, Nesobasis has shown to be monophyletic in previous phylogenetic analyses. Using additional species in this study, we investigate the phylogenetic relationships between Nesobasis and other damselflies from the region, specifically the endemic Vanuatubasis Ober & Staniczek, 2009 from the neighboring island archipelagos of Vanuatu. The relationship between these taxa has not yet been examined with molecular data. Five genes were used in a maximum likelihood phylogenetic reconstruction and examined morphological data to determine the relationship between these genera. Our results recover three distinct clades overall with Vanuatubasis nested within Nesobasis (i.e., non-monophyletic). Vanuatubasis is sister to the longistyla and erythrops groups. The third group, comosa, was found sister to the clade of Vanuatubasis (longistyla + erythrops). As a result of these findings, we propose the new genus, Nikoulabasis gen. nov.