Testing the phylogenetic utility of morphological character systems, with a revision of Creophilus leach coleoptera: Staphylinidae

Many studies have examined the phylogenetic utility of different kinds of molecular data, and have often compared these with morphology. However, relatively few studies have phylogenetically evaluated different morphological character systems. Using the Creophilus complex, the phylogenetic utility of external structural characters, male genitalia, female genitalia, and chaetotaxy of adults is examined for the first time in the megadiverse beetle family Staphylinidae. A data set of 121 phylogenetically informative characters of 24 terminal taxa was analysed separately and simultaneously using parsimony and the phylogenetic utility of each partition was compared with widely used statistics and support measures. External structures had the least homoplasy, resolved the most nodes separately, and largely determined the topology of the simultaneous analysis. Male and female genitalia contributed phylogenetic signal mostly congruent with external characters. Despite extensive homoplasy, chaetotaxy contributed the majority of hidden support, and was critical for resolving several terminal nodes in the simultaneous analysis. All character systems were informative throughout the tree, and when combined provided the best-supported hypothesis. However, there is a need to distinguish hidden support from dispersion of homoplasy when combining data sets of varying quality. The Creophilus complex, Creophilus Leach, Liusus Sharp, and the Creophilus erythrocephalus (Fabricius) and C. maxillosus (Linnaeus) species-groups are each strongly supported monophyletic groups. Hadrotes Mäklin is not monophyletic and Hadrotes wakefieldi Cameron is the sister-species of the rest of the Creophilus complex, but included within it. Creophilus is revised to include 12 species, including Creophilus galapagensis sp. nov. and C. rekohuensis sp. nov. Creophilus huttoni (Broun) is removed from synonymy with C. oculatus (Fabricius), and C. insularis (Fauvel), C. villipennis Kraatz, and C. violaceus (Fauvel) are synonymized under C. flavipennis (Hope) comb. et stat. nov. © 2011 The Linnean Society of London