15 December 2019 Male genital sclerites in Coniopterygidae – A tightrope dance Toward a homologization of male genital sclerites in Coniopterygi dae (Neuroptera) – A tightrope dance Ulrike Aspöck Natural History Museum, 2nd Zoological Department, Burgring 7, A-1010 Vienna, Austria; [email protected]; [email protected] Department of Integrative Zoology, University of Vienna, Althanstraße 14, A-1090 Vienna, Aus- tria Received 24th September 2018; revised and accepted 14th February 2019 Abstract. Archaeognathan Machilidae serve as a model for the serially homologous sclerites of the terminal abdominal segments 9, 10, and 11: the gonocoxites, gonostyli and gonapophy- ses, which have copulative function in male Neuropterida. The identity of these genital scle- rites may be camouflaged by excessive modelling of form, reduction, loss or fusion of single sclerites to complexes. If the identity of a sclerite is problematic, then a hypothesis based on a gonocoxite-concept has greater heuristic value than to interpret it as an accessorial de novo structure and to assign a new name. Coniopterygidae, with a fore wing length less than 6 mm, are truly the dwarfs among Neuroptera and comprise almost 580 known species representing three subfamilies. i) Brucheiserinae – apart from their unusual eidonomic appearance – surprise us with a complete set of genital sclerites; the fact that they possess a callus cerci indicates a rather plesiomorphic pattern within the family. ii) Coniopteryginae – in spite of their heteroge- neity – allow us to distinguish the gonocoxite-complexes 9, 10, and 11. iii) Aleuropteryginae are also extremely heterogeneous and confront us with completely invaginated tergite and sternite 9, as in the genus Aleuropteryx, nevertheless the gonocoxite-complexes 9, 10 and 11 are otherwise recognizable. The male gonocoxite-complex 10 generally serves as a morphological landmark in Coniopterygidae. The present hypothesis of a sister-group relationship between Aleuropterygi- nae and the clade Brucheiserinae + Coniopteryginae remains valid. The phylogenetic position of Coniopterygidae within the order Neuroptera – either as sister-group of all other families or of the dilarid-clade or nested somewhere else – might be resolved by the current campaign of homologization. Figure 1. Coniopteryx pygmaea Enderlein, 1906, on a pine nee- dle, habitus. Photo H. Bruckner. Length of fore wing: 2.4 mm Proceedings of the XIII International Symposium of Neuropterology, 17–22 June 2018, Laufen, Germany63 Pages 63-78, DOI:10.5281/zenodo.3569381 Ulrike Aspöck Background History of the early research on the neuropteran family Coniopterygidae Burmeister, 1839, was thoroughly documented almost ten years ago by Aspöck & Aspöck (2009), who emphasized that Coniopterygidae were once primarily associated with Psocidae. With a fore wing length between 1.2 to 6 mm, Coniopterygidae (Fig. 1) are the dwarfs among Neuropterida. Nonetheless, they have been a matter of permanent excitement concerning their systematics and phylogeny as they light-footedly switch seats in the evolutionary carousel of the Neuropterida. In phylogenetic analyses of the order Neu- roptera, Coniopterygidae emerge either as the sister-group to all other families, or they are nested within a tree, predominately as the sister-group to the dilarid-clade. Analyses based on molecular data, e.g., mitochondrial phylogenomics (Wang et al. 2017; Fig. 2) or anchored phylogenomics (Winterton et al. 2018; Fig. 3), corroborate each other in Figure 2. Mitochondrial phylogenomics pre- Figure 3. Anchored phylogenomics showing senting Coniopterygidae as sister-group to all Coniopterygidae as sister-group to all other other families of the order Neuroptera. Within families of the order Neuroptera. Myrmele- the monophyletic Myrmeleontiformia (pink) ontiformia (pink are disrupted, and the family the family Myrmeleontidae is paraphyletic. Af- Myrmeleontidae is paraphyletic. After Win- ter Wang et al. (2017). terton et al. (2018). 64 Male genital sclerites in Coniopterygidae – A tightrope dance presenting Coniopterygidae as the sister-group to all other families. Nonetheless, there are severe conflicts between these trees concerning the positions of other families, e.g., the separation of the Hemerobiidae and Chrysopidae, and the disruption of the Myr- mele ontiformia in the tree gained by anchored phylogenomics. Alternatively in several morphology-based trees, but also in a previous molecular tree (Haring & Aspöck 2004), Coniopterygidae emerge as sister-group to the dilarid-clade: either with Nevrorthidae as the sister-group to all other families, a result which is main- ly based on the morphology of genital sclerites (Aspöck & Aspöck 2008; Fig. 4), or with Sisyridae as sister-group to all other Neuropteran families, which is mainly based on head morphology (Randolf et al. 2014; Fig. 5). Figure 4. Phylogeny based on morphology of Figure 5. Phylogeny based on adult head mor- the genital sclerites inferring that the Nevror- phology presenting Sisyridae as sister-group to thidae are the sister-group to all other families, all other families, Nevrorthidae as sister-group and Coniopterygidae as sister-group to the di- to the rest and Coniopterygidae as sister- larid clade. After Aspöck & Aspöck (2008). group to the dilarid-clade. After Randolf et Top insert: Nevrorthus apatelios H.A., U.A. & al. (2014). Top insert: Sisyra terminalis Curtis, Hölzel, 1977. Photo: P. Duelli. 1854. Photo: H. Rausch. 65 Ulrike Aspöck In the fancy cake chart of Neuroptera (Aspöck & Aspöck 2007) the slice representing Coniopterygidae is medium-sized (Fig. 6). The approximately 580 species Oswald( & Machado 2018) are assigned to three extremely heterogeneous subfamilies: i) the en- igmatic Brucheiserinae Navás, 1927 (Fig. 7), with only a few known species restricted to certain arid and semiarid areas of South America, and ii) the species-rich subfamilies Coniopteryginae Burmeister, 1839 (Fig. 8) and iii) Aleuropteryginae Enderlein, 1905 (Fig. 9), both of which have a worldwide distribution. The enigmatic Brucheiserinae, with hitherto only a few known species, are restricted to some arid and semiarid territories of South America, while the species-rich subfamilies Coniopteryginae and Aleuropteryginae are distributed worldwide. The first modern monograph on Coniopterygidae and an additional check-list of the species of the world (Meinander 1972, 1990) were recently updated (Sziráki 2011). The sustaining current phylogenetic hypothesis places Aleuropteryginae (Fig. 10) as the sister-group to the clade Brucheiserinae + Coniopteryginae (Figs 11, 12; Zimmer- Figure 6. In the fancy cake chart of Neuroptera (from Aspöck & Aspöck 2007) the section of Coniopterygidae (light blue slice), comprising almost 580 species, is of medium size. Figures 7–9. Representatives of the three subfamilies of the Coniopterygidae. 7 – Brucheiserinae, Brucheiser penai Riek, 1975 (afterRiek 1975); 8 – Coniopteryginae, Coniopteryx pygmaea Enderlein, 1906. Photo: H. Bruckner; 9 – Aleuropteryginae, Aleuropteryx juniperi Ohm, 1968. Photo: H. Rausch. 66 Male genital sclerites in Coniopterygidae – A tightrope dance mann et al. 2009). The larvae of Brucheiserinae and Coniopteryginae have laterally ex- tended heads – a result of the prominence of the ocular regions. Both subfamilies have short sucking tubes which barely project beyond the tip of the labral margin (Figs 11, 12). These characters have been interpreted as synapomorphies. Consequently, the plicatures (Figs 13, 14) of the abdomen, which are expressed in Brucheiserinae and Aleuro pteryginae but absent in Coniopteryginae, must belong to the ground pattern of Coniopterygidae and were presumably secondarily lost in Coniopteryginae. The pos- session of wax glands (Fig. 15) and the wax covering of body and wings – a phenom- enon which characterizes adult Coniopteryginae and Aleuropteryginae but which is absent in Brucheiserinae – is apparently an apomorphy of the family Coniopterygidae that has been secondarily lost in Brucheiserinae. Figures 10–12. The larvae of Brucheiserinae (Fig. 11) and Coniopteryginae (Fig. 12) are charac- terized by laterally extended heads and short sucking tubes – synapomorphies of both families. The current hypothesis posits a sister-group relationship of Aleuropteryginae (Fig. 10) to the clade Brucheiserinae + Coniopteryginae (Figs 11, 12; from Zimmermann et al. 2009). Figures 13, 14. Aleuro pteryx juniperi, 13: abdomen with plicatures, 14: closed plicature (from Zimmermann et al. 2009). The plicatures of the abdomen are expressed in Aleuropteryginae and Brucheiserinae, but are lost in Coniopteryginae. Figure 15. Semidalis aleyrodiformis (Stephens, 1836), wax gland. From Zimmermann et al. (2009). The possession of wax glands is a joint character of Aleuropteryginae and Conio- pteryginae, and they are apparently lost in Brucheiserinae. 67 Ulrike Aspöck Genital sclerites – The favorite toys of evolution Neuropterida (Fig. 17) and especially Coniopterygidae (Fig. 16) are equipped with ex- cessively heterogeneous male genital sclerites, which are of high phylogenetic relevance. Interestingly and worth mentioning – as a paradox – is fact that the head morphology and anatomy of Coniopterygidae are characterized by a considerable degree of mini- aturization (Randolf et al. 2017), while the genital sclerites – on the contrary – show no corresponding signs of these phenomena. Owen’s (1843) famous definition of homology is given in his glossary: »HOMO- LOGUE The same organ in