We used 766 bp of DNA sequence data from the mitochondrial cytochrome oxidase I gene to reconstruct a phylogeny for 39 of 43 Ips species, many of which are economically important bark beetles. The phylogeny was reconstructed using equally weighted and weighted parsimony. In both analyses, peripheral clades were well supported while internal clades were poorly supported. Phylogenetic analysis of translated amino acids produced a poorly resolved tree that was discordant with trees reconstructed with nucleotide sequence data. Two main conclusions are drawn about the monophyly of Ips and traditional systematic groups within Ips. First, Ips is monophyletic only when I. mannsfeldi, I. nobilis, and the concinnus and latidens species groups are excluded. The latidens group, I. mannsfeldi, and I. nobilis form a monophyletic group with 3 Orthotomicus species, while the concinnus group has a more basal position. Second, the majority of the species groups in the current classification for Ips are not monophyletic. European Ips species do not form a monophyletic group, contrary to common usage, and are dispersed on the phylogenetic tree among North American species. These results indicate that a formal systematic revision of Ips is needed.
Copyright 2000 Academic Press.