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This chapter introduces the basic approaches to systematics—using morphological and molecular data—and it considers the history of systematic analysis in odonates. In this chapter we address how different molecular methods have been applied at different times to the study of odonate systematics. We also review the current understanding of relationships within the three main suborders (Zygoptera, Anisozygoptera and Anipoptera) and highlight areas in need of further research. We then look at how systematics tools can be applied to address questions in ecology and evolution, consider some questions that systematics cannot answer, and review the future of odonate systematic research.

SummaryDragonflies and damselflies, representing the insect order Odonata, are among the earliest flying insects with living (extant) representatives. However, unravelling details of their long evolutionary history, such as egg laying (oviposition) strategies, is impeded by unresolved phylogenetic relationships, an issue particularly prevalent in damselfly families and fossil lineages. Here we present the first transcriptome-based phylogenetic reconstruction of Odonata, analyzing 2,980 protein-coding genes in 105 species representing nearly all of the order’s families (except Austropetaliidae and Neopetaliidae). All damselfly families and most dragonfly families are recovered as monophyletic groups. Our Molecular clock estimates suggest that crown-Zygoptera (damselflies) and -Anisoptera (dragonflies) both arose during the late Triassic. Several of the observed long inner branches in our topology are indicative of the extinction of once flourishing lineages. We also find that exophytic egg laying behaviour with a reduced ovipositor evolved in certain dragonflies during the late Jurassic / early Cretaceous. Lastly, we find that certain fossils have an unexpected deterring impact in divergence dating analysis.

Summary Dragonflies and damselflies are among the earliest flying insects with extant representatives. However, unraveling details of their long evolutionary history, such as egg laying (oviposition) strategies, is impeded by unresolved phylogenetic relationships, particularly in damselflies. Here we present a transcriptome-based phylogenetic reconstruction of Odonata, analyzing 2,980 protein-coding genes in 105 species representing nearly all the order’s families. All damselfly and most dragonfly families are recovered as monophyletic. Our data suggest a sister relationship between dragonfly families of Gomphidae and Petaluridae. According to our divergence time estimates, both crown-Zygoptera and -Anisoptera arose during the late Triassic. Egg-laying with a reduced ovipositor apparently evolved in dragonflies during the late Jurassic/early Cretaceous. Lastly, we also test the impact of fossil choice and placement, particularly, of the extinct fossil species, †Triassolestodes asiaticus, and †Proterogomphus renateae on divergence time estimates. We find placement of †Proterogomphus renateae to be much more impactful than †Triassolestodes asiaticus., Graphical abstract, Highlights • Relationships of dragonflies and damselflies are unraveled using transcriptomes • Earliest flying insects – Odonata and extinct relatives – date back to Permian period • Both extant dragonflies and damselflies started diverging in the Triassic period, Evolutionary biology; Phylogenetics

Phylogenetic relationships among subgroups of cockroaches and termites are still matters of debate. Their divergence times and major phenotypic transitions during evolution are also not yet settled. We addressed these points by combining the first nuclear phylogenomic study of termites and cockroaches with a thorough approach to divergence time analysis, identification of endosymbionts, and reconstruction of ancestral morphological traits and behaviour. Analyses of the phylogenetic relationships within Blattodea robustly confirm previously uncertain hypotheses such as the sister-group relationship between Blaberoidea and remaining Blattodea, and Lamproblatta being the closest relative to the social and wood-feeding Cryptocercus and termites. Consequently, we propose new names for various clades in Blattodea: Cryptocercus + termites = Tutricablattae; Lamproblattidae + Tutricablattae = Kittrickea; and Blattoidea + Corydioidea = Solumblattodea. Our inferred divergence times contradict previous studies by showing that most subgroups of Blattodea evolved in the Cretaceous, reducing the gap between molecular estimates of divergence times and the fossil record. On a phenotypic level, the blattodean ground-plan is for egg packages to be laid directly in a hole while other forms of oviposition, including ovovivipary and vivipary, arose later. Finally, other changes in egg care strategy may have allowed for the adaptation of nest building and other novelties.

Boyeria irene and Boyeria cretensis are species of spotted dragonflies belonging to the ‘darner’ family, Aeshnidae. In 1991, Peters classified Boyeria from Crete as B. cretensis, based on adult morphological characters. In this study, we used molecular evidence to determine if indeed B. irene and B. cretensis are different species. DNA was sequenced from samples of B. irene (from France, Switzerland, Tunisia, Spain and Italy) and B. cretensis (from Crete). These species were recovered as two different clades with strong support. We conclude that B. irene and B. cretensis are different species, with evidence based on molecular and morphological differences. In addition, we present the first phylogenetic hypothesis for Boyeria for which we have sequenced all but three species. Lastly, we discuss different scenarios that may have led to the present-day distribution and speciation patterns of Mediterranean Boyeria.

Molecular data along with fossils are being used increasingly to recover time-calibrated phylogenetic trees. Recently there have been manuscripts that have used divergence dating to understand evolutionary history of certain clades within Odonata (dragonflies and damselflies), yet the number of such articles is still low. We examined the Odonata fossil record and made a list of fossils that can be used for divergence time analysis. In this manuscript we provide a detailed review of the known crown group fossils for the order Odonata and nine nodes within this clade: Zygoptera, Epiprocta, Anisoptera, Aeshnidae, Gomphidae, Cavilabiata, Macromiidae, Corduliidae, and Libellulidae. Manpreet Kaur Kohli. Rutgers University, 195 University Ave, Newark, NJ 07102, USA. mkk24@njit.edu Jessica L. Ware. Rutgers University, 195 University Ave, Newark, NJ 07102, USA. jware@amnh.org Gunter Bechly. Department of Paleontology, State Museum of Natural History, Rosenstein 1, 70191 Stuttgart, Germany. guenter.bechly@smns-bw.de (corresponding author)