Phylogeny of the central-western Pacific subgenus Inseliellum (Diptera: Simuliidae)

Abstract

Subgenus-level groups of western and central Pacific Simuliidae are briefly assessed using phylogenetic principles. Inseliellum and Nevermannia (ruficorne-group) are established as sister taxa. Detailed morphological analysis of 32 species of Inseliellum shows that the Micronesian Simulium trukense is the basal lineage. Austral and Cook islands species, plus those of the Marquesas Islands, form the next basal clade. Simulium malardei is the sister taxon of all other Society Islands species, including Simulium adamsoni from the Marquesas Islands. There are three clades: the tahitiense-group, which is weakly supported, the castaneum-group, which is moderately well supported, and the oviceps-group, which is strongly supported. One of two most parsimonious phylogenies that is in agreement with independent cytological information is presented. Habitat preference and larval behaviour are optimized on this phylogeny, providing information about evolutionary trends. Brief comments are made regarding geological development of the habitats of larvae of some species.