The phylogeny of Anisoptera, dragonflies in the strict sense, has proven to be notoriously difficult to resolve. Based on morphological characters, several recent publications dealing with the phylogeny of dragonflies proposed contradicting inter- and intrafamily relationships. We explored phylogenetic information content of mitochondrial large-subunit (LSU) and small-subunit (SSU) ribosomal gene fragments for these systematic problems. Starting at published universal primers, we developed primer sets suitable for amplifying large parts of the LSU and SSU rRNA genes within dragonflies. These fragments turned out to harbor sufficient phylogenetic information to satisfyingly resolve intrafamily relationships, but they contain insufficient phylogenetic structure to permit reliable conclusions about several interfamily relationships. We demonstrate that decay of phylogenetic signal progresses from intrafamily to interfamily to outgroup relationships and is correlated with an increase of genetic distances. As expected, signal decay is most pronounced in fast-changing sites. Additionally, base composition among fast-changing sites significantly deviates from the expected homogeneity. Homogeneity of base composition among all included taxa was restored only after removing fast-changing sites from the data set. The molecular data tentatively support interfamily relationships proposed by the most recent publication based on morphological characters of fossil and extant dragonflies.

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The application of mixed nucleotide ⁄ doublet substitution models has recently received attention in RNA-based phylogenetics. Within a Bayesian approach, it was shown that mixed models outperformed analyses relying on simple nucleotide models. We analysed an mt RNA data set of dragonflies representing all major lineages of Anisoptera plus outgroups, using a mixed model in a Bayesian and parsimony (MP) approach. We used a published mt 16S rRNA secondary consensus structure model and inferred consensus models for the mt 12S rRNA and tRNA valine. Secondary structure information was used to set data partitions for paired and unpaired sites on which doublet or nucleotide models were applied, respectively. Several different doublet models are currently available of which we chose the most appropriate one by a Bayes factor test. The MP reconstructions relied on recoded data for paired sites in order to account for character covariance and an application of the ratchet strategy to find most parsimonious trees. Bayesian and parsimony reconstructions are partly differently resolved, indicating sensitivity of the reconstructions to model specification. Our analyses depict a tree in which the damselfly family Lestidae is sister group to a monophyletic clade Epiophlebia + Anisoptera, contradicting recent morphological and molecular work. In Bayesian analyses, we found a deep split between Libelluloidea and a clade ÔAeshnoideaÕ within Anisoptera largely congruent with TillyardÕs early ideas of anisopteran evolution, which had been based on evidently plesiomorphic character states. However, parsimony analysis did not support a clade ÔAeshnoideaÕ, but instead, placed Gomphidae as sister taxon to Libelluloidea. Monophyly of Libelluloidea is only modestly supported, and many inter-family relationships within Libelluloidea do not receive substantial support in Bayesian and parsimony analyses. We checked whether high Bayesian node support was inflated owing to either: (i) wrong secondary consensus structures; (ii) under-sampling of the MCMC process, thereby missing other local maxima; or (iii) unrealistic prior assumptions on topologies or branch lengths. We found that different consensus structure models exert strong influence on the reconstruction, which demonstrates the importance of taxon-specific realistic secondary structure models in RNA phylogenetics.

Secondary structures of the most conserved part of the mt 16S rRNA gene, domains IV and V, have been recently analysed in a comparative study. However, full secondary structures of the mt LSU rRNA molecule are published for only a few insect species. The present study presents full secondary structures of domains I, II, IV and V of Odonates and one representative of mayflies, Ephemera sp. The reconstructions are based on a comparative approach and minimal consensus structures derived from sequence alignments. The inferred structures exhibit remarkable similarities to the published Drosophila melanogaster model, which increases confidence in these structures. Structural variance within Odonates is homoplastic, and neighbour-joining trees based on tree edit distances do not correspond to any of the phylogenetically expected patterns. However, despite homoplastic quantitative structural variation, many similarities between Odonates and Ephemera sp. suggest promising character sets for higher order insect systematics that merit further investigations.

-Phylogénie et classification des Stenophlebioptera (Insecta, Odonata, Epiproctophora)-Les Juraheterophlebiidae, nouvelle famille de la lignée "hétérophlebioïde", les Henrotayiidae, nouvelle famille de la lignée "anisoptéroïde", les Prostenophlebiidae et les Liassostenophlebiidae, nouvelles familles de Stenophlebioptera, et trois nouveaux genres et espèces de Stenophlebiidae sont décrits du Mésozoïque d'Allemagne, Espagne, Angleterre, Kazakhstan et Mongolie. Les positions phylogénétiques des familles Erichschmidiidae et Gondvanogomphidae sont discutées. Un essai d'analyse phylogénétique des Anisopteromorpha est proposé. Ces nouvelles données étendent significativement nos connaissances sur la distribution paléogéographique des Stenophlebioptera et des Epiproctophora.

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The odonatan fauna of the Late Eocene of the Isle of Wight is revised. The following taxa are revised or described: the gomphaeschnids Oligoaeschna? anglica Cockerell & Andrews, 1916 and Anglogomphaeschna eocenica gen. et sp. nov.; the aeshnids ‘Oplonaeschna’ vectensis Cockerell & Andrews, 1916, Aeschnophlebia andreasi Nel et al., 2005, Oligaeschna wedmanni sp. nov., and a ‘Gynacanthinae’ species; Neophya legrandi sp. nov., first fossil representative of the Cordulephyidae; three undescribed ‘Corduliidae’; Eomacrodiplax incompleta gen. et sp. nov., first fossil representative of the Urothemistidae; the second representative of the Palaeogene family Bolcathoridae; a Thaumatoneuridae Dysagrionini species A; the megapodagrionid Oligoargiolestes oligocenum Kennedy, 1925; the two hypolestids Anglohypolestes fasciata gen. et sp. nov. and Eohypolestes hooleyi gen. et sp. nov.; the coenagrionid ‘Enallagma' oligocena Cockerell & Andrews, 1916, and three other undescribed species; Angloprotoneura emilielacroixi gen. et sp. nov., first fossil European representative of the damselfly family Protoneuridae; and the lestid Lestes aff. regina Théobald, 1937. This fauna has strong similarities with the Recent Afrotropical and Indo-Malayan Odonata, suggesting a warm palaeoclimate for the Late Eocene of the Isle of Wight. ‘Megalestes’ anglicus Cockerell, 1915 is a Zygoptera Lestiformia or Coenagrionomorpha of uncertain affinities.

Here we provide a checklist of the odonates from Amazonas state, Brazil. We registered 324 species and 101 genera, making Amazonas the Brazilian state with the most Odonata species recorded. The families with the highest number of species were Coenagrionidae with 32 genera and 101 species, followed by Libellulidae with 28 genera and 100 species and Gomphidae with 12 genera and 45 species. Some regions of Amazonas state remain poorly explored, such as the southern area, and large municipalities, such as São Gabriel da Cachoeira. This work underlines the importance of the biological diversity from Amazonas state and the Amazonian Biome for Odonata species richness in Brazil and shows that many areas in the world’s largest tropical forest have not yet been sampled.