The Phylogeny of the Extant Hexapod Orders

Abstract

Morphological and molecular data are marshalled to address the question of hexapod ordinal relationships. The combination of 275 morphological variables, 1000 bases of the small subunit nuclear rDNA (18S), and 350 bases of the large subunit nuclear rDNA (28S) are subjected to a variety of analysis parameters (indel and transversion costs). Representatives of each hexapod order are included with most orders represented multiply. Those parameters that minimize character incongruence (ILD of Mickevich and Farris, 1981, Syst. Zool. 30, 351–370), among the morphological and molecular data sets are chosen to generate the best supported cladogram. A well-resolved and robust cladogram of ordinal relationships is produced with the topology (Crustacea ((Chilopoda Diplopoda) ((Collembola Protura) ((Japygina Campodeina) (Archaeognatha (Zygentoma (Ephemerida (Odonata ((((Mantodea Blattaria) Isoptera) Zoraptera) ((Plecoptera Embiidina) (((Orthoptera Phasmida) (Grylloblattaria Dermaptera)) ((((Psocoptera Phthiraptera) Thysanoptera) Hemiptera) ((Neuropteroidea Coleoptera) (((((Strepsiptera Diptera) Mecoptera) Siphonaptera) (Trichoptera Lepidoptera)) Hymenoptera)))))))))))))).