Systematic Entomology (2001) 26, 73-86 Cladistic analysis of Neuroptera and their systematic position within Neuropterida (Insecta: Holometabola: Neuropterida: Neuroptera) ULRIKE ASPOCK, JOHN D. PLANT* andHANS L. NEMESCHKAL* Naturhistorisches Museum, Vienna and "Institute of Zoology, University of Vienna, Austria Abstract. A phylogenetic analysis of Neuroptera using thirty-six predominantly morphological characters of adults and larvae is presented. This is the first computerized cladistic analysis at the ordinal level. It included nineteen species representing seventeen families of Neuroptera, three species representing two families (Sialidae and both subfamilies of Corydalidae) of Megaloptera, two species representing two families of Raphidioptera and as prime outgroup one species of a family of Coleoptera. Ten equally most parsimonious cladograms were found, of which one is selected and presented in detail. The results are discussed in light of recent results from mental phylogenetic cladograms. The suborders Nevrorthi- formia, Myrmeleontiformia and Hemerobiiformia received strong support, however Nevrorthiformia formed the adelphotaxon of Myrmeleontiformia + Hemerobiiformia (former sister group of Myrmeleontiformia only). In Myrmeleontiformia, the sister-group relationships between Psychopsidae + Nemopteridae and Nymphidae + (Myrmeleontidae + Ascalaphidae) are corroborated. In Hemerobiiformia, Ithonidae + Polystoechotidae js confirmed as the sister group of the remaining families. Dilaridae + (Mantispidae + (Rhachiberothidae + Berothidae)), which has already been proposed, is confirmed. Chrysopidae+Osmylidae emerged as the sister group of a clade comprising Hemerobiidae + ((Coniopterygidae + Sisyridae) + (dilarid clade)). Despite the sister-group relationship of Coniopterygidae + Sisyridae being only weakly supported, the position of Coniopterygidae within the higher Hemerobiiformia is corroborated. At the ordinal level, the analysis provided clear support for the hypothesis that Megaloptera + Neuroptera are sister groups, which upsets the conventional Megaloptera + Raphidioptera hypothesis. Introduction Neuroptera, with about 6000 species in seventeen families, is an ancient order of insects that exhibit an exceptionally broad range of morphological and biological diversity. The mono- phyly of the group has not been in doubt and is mainly based on morphological characters of the larvae. 'The sucking tubes of the larvae are not only their most spectacular autapomorphy but also the magic formula for a rich evolutionary aquatic and terrestrial diversification ...' (Aspock, 1992). Together with Correspondence: Univ.-Doz. Dr Ulrike Aspock, 2 Zoologische Abteilung, Naturhistorisches Museum Wien, Postfach 417, Burgring 7, A-1014 Vienna, Austria. E-mail: ulrike.aspoeck@nhm-wien.ac.at Cordially dedicated to Horst Aspock on the occasion of his 6oCh birthday (21 July 1999). Megaloptera (270 species, two families) and Raphidioptera (205 species, two families), they constitute superorder Neuropterida, which is commonly considered to be the most primitive Holometabola. The comparatively small number of species, heterogeneity of taxa, vicariant distribution patterns and rich fossil record all suggest that the golden age of Neuropterida has long expired. The extant fauna is but a remnant of that of former times and many groups can be characterized as living fossils (Aspock, 1998; Aspock & Aspock, 1994, 1999). The monophyly of Neuropterida and their systematic position within Holometabola as the sister group of Coleoptera are generally accepted. These hypotheses are established by numerous arguments that are to some extent cryptic and sophisticated (Hennig, 1969, 1981; Mickoleit, 1973; Aspock et al., 1980; Paulus, 1986; Aspock et al., 1991; i 2001 Blackwell Sclence Ltd 73