A revised interpretation of attachment structures in Hexapoda with special emphasis on Mantophasmatodea

Abstract

Characters of hexapod attachment structures were analysed cladistically together with 110 additional morphological characters of immatures and adults. The results suggest the monophyly of Hexapoda, Ellipura, Diplura + Ectognatha, and Dicondylia. Lepidothrichidae is either the sister group of the remaining Dicondylia or part of a clade Zygentoma. Odonata is the sister group of Neoptera, and Plecoptera possibly the sister group of the remaining neopteran orders. Pliconeoptera are paraphyletic. Embioptera were placed as sistergroup of a clade comprising the remaining Pliconeoptera, Paraneoptera and Endopterygota. The branching pattern of the majority of the “lower neopteran” groups is Dermaptera + ((Dictyoptera + (Orthoptera + Phasmatodea)) + (Grylloblattodea + Mantophasmatodea)). The sister group relationship between Mantophasmatodea and Grylloblattodea is only weakly supported. Zoraptera were placed as sister group of Acercaria (Paraneoptera). The monophyly of Psocodea and Hemiptera was confirmed. Paraneoptera are the sister group of Endopterygota. Strepsiptera were placed as sister taxon to the remaining Endopterygota. Coleoptera + Neuropterida is weakly supported statistically. They are placed as sister group of Hymenoptera + (Amphiesmenoptera + Antliophora). The interrelationships within Antliophora remain uncertain. Attachment devices that have evolved in an apterygote lineage are the tufts of curved hairs on the apical tarsus of archaeognathan species (scopulae). Attachment pads were absent in the groundplan of Pterygota. The arolium is likely a derived groundplan feature of Neoptera, with secondary loss in several groups. It is usually smooth on its surface. The hairy surface of the greatly enlarged arolium and the hairy surface of the euplantulae are autapomorphies of Mantophasmatodea. Pad-like euplantulae are a potential synapomorphy of the clade comprising Dictyoptera, Phasmatodea, Orthoptera, Grylloblattodea (strongly reduced in size) and Mantophasmatodea. Hairy or smooth pulvilli have evolved several times independently. Hairy soles of tarsomeres are present in Embioptera, Dermaptera, Megaloptera, Raphidioptera, Coleoptera (groundplan) and Stylopidia (absent in the groundplan of Strepsiptera). The phylogenetic interpretation of this character is ambiguous. An eversible pretarsal vesicle is autapomorphic for Thysanoptera and a fossula spongiosa for Piratinae (Reduviidae). An extended empodium occurs in Nematocera excl. Tipulomorpha and in Tabanoidea. The presence of hairy pulvilli and the loss of the arolium are potential apomorphies of Diptera excl. Tipulomorpha. Plantar lobes are a derived groundplan feature of Hymenoptera and partly or completely reduced in Apocrita.