Phylogeny of the central-western pacific subgenus Inseliellum (Diptera : simuliidae)

Subgenus-level groups of western and central Pacific Simuliidae are briefly assessed using phylogenetic principles. Inseliellum and Nevermannia (rufic orne-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 M arquesas Islands, form the next basal clade. Simulium malardei is the siste r taxon of all other Society Islands species, including Simulium adamsoni f rom the Marquesas Islands. There are three clades: the tahitiense-group, wh ich is weakly supported, the castaneum-group, which is moderately well supp orted, 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 optim ized on this phylogeny, providing information about evolutionary trends. Br ief comments are made regarding geological development of the habitats of l arvae of some species.