Ancient dispersal history may be obscured by subsequent dispersal events. Therefore, we intend to investigate the biogeography of metriorrhynchine net-winged beetles, a group characterized by limited dispersal propensity. We used DNA data to construct phylogenies and the BayesTraits and RASP programs to identify putative ancestral areas. Further, we inferred ultrametric trees to estimate the ages of selected nodes. The time frame is inferred from tectonic calibrations and the general mutation rate of the mitochondrial genes. Metriorrhynchini consists of two lineages with Afro/Oriental and Australian distributions. The basal lineages originated in Eastern Gondwana after the split of Australia, India and Madagascar; the Afrotropical and Madagascar Metriorrhynchini separated from the Oriental clades 65 and 62 mya. Several already diversified lineages colonized continental Asia 55–35 mya. A few genera of the Australian clade dispersed to the Oriental region 5–15 mya and reached Eastern India and Southern China. Only Xylobanus crossed the Makassar Strait to Sulawesi and does not occur further to the east. The current distribution of Metriorrhynchini is a result of drifting on continental fragments and over-sea dispersal events limited to a few hundreds of kilometers. We conclude that: (1) Afrotropical and Madagascar lineages originated independently from dispersal events during India's drift to the north and the Mozambique Channel completely isolates the respective faunas since then; (2) Oriental fauna is a recently established mixture of the Indian and Australian lineages, with predominance of the older Indian clades; (3) The fauna of islands located north of Australia colonized Sulawesi after collision with the Sundaland margin and the species rich Australian lineages did not reach Western Wallacea or the Philippines. Our results suggest an impact of subtle differences in biological characteristics on biogeographic history of individual lineages, when mostly lowland and flower-visiting lineages were able to disperse across sea channels.

BackgroundRhinorhipidae Lawrence, 1988 is an enigmatic beetle family represented by a single species, Rhinorhipus tamborinensis Lawrence, 1988, from Australia, with poorly established affinities near the superfamily Elateroidea (click beetles, soldier beetles and fireflies) or the more inclusive series (infraorder) Elateriformia. Its evolutionary position may inform the basal relationships of the suborder Polyphaga, the largest clade of Coleoptera.ResultsWe analyzed four densely sampled DNA datasets of major coleopteran lineages for mitogenomes, rRNA genes and single copy nuclear genes. Additionally, genome sequencing was used for incorporation of R. tamborinensis into a set of 4220 orthologs for 24 terminals representing 12 polyphagan superfamilies. Topologies differed to various degrees, but all consistently refute the proposed placement of Rhinorhipidae in Elateroidea and instead indicate either sister relationships with other Elateriformia, frequently together with Nosodendridae, another divergent small family hitherto placed in Derodontoidea, or in an isolated position among the deepest lineages of Polyphaga. The phylogenomic analyses recovered Rhinorhipus in a sister position to all other Elateriformia composed of five superfamilies. Therefore, we erect the new superfamily Rhinorhipoidea Lawrence, 1988, stat. Nov., with the type-family Rhinorhipidae. The origins of the Rhinorhipidae were dated to the Upper Triassic/Lower Jurassic at the very early phase of polyphagan diversification.ConclusionsThus, Rhinorhipidae adds another example to several recently recognized ancient relict lineages which are interspersed within contemporaneous hugely species-rich lineages of Coleoptera.Electronic supplementary materialThe online version of this article (10.1186/s12983-018-0262-0) contains supplementary material, which is available to authorized users.

Synchonnus Waterhouse, 1879 from Australia is revised. Achras Waterhouse, 1879 and Enylus Waterhouse, 1879 are found to be junior synonyms of Synchonnus due to the absence of diagnostic characters and result in the new combinations of Synchonnus amplus (Kleine, 1930), S. limbatum (Waterhouse, 1877), and S. segregatus (Waterhouse, 1879). Synchonnus is reported from the Australian mesic and monsoon zones, and 11 new species are described: S. flavonotatum sp. nov., S. maseki sp. nov., S. ailaketoae sp. nov., S. dubenovae sp. nov., S. chilvertonensis sp. nov., S. slipinskii sp. nov., S. monteithi sp. nov., S. eungellensis sp. nov., S. crypticum sp. nov., S. variabilis sp. nov. and S. campestris sp. nov. The morphology-based species limits are compared with delimitation inferred from the shape of the phylogenetic tree and genetic distance. DNA-based species limits agree with morphological delimitation in two clades, but a deep conflict was identified in another clade of Synchonnus consisting of three species with allopatric distributions and diversified genitalia, but strong similarities in cox1 mtDNA sequences. The failure of molecular species delimitation in some Synchonnus points to our inability to predict the performance of a barcoding approach even in closely related lineages and calls for an integrative taxonomical approach whenever possible. The Synchonnus fauna of Australia is presented as highly diverse and fragmentation of habitat in the last~15 million years is hypothesised as the principal factor leading to the observed alpha-taxonomic diversity.

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The classification of Metriorrhynchini, the most diverse lineage of net-winged beetles (Lycidae) containing ~ 1400 species, is revised on the basis of three-marker molecular phylogeny of 175 ingroup taxa, and the adult and larval morphology. The study uses the molecular phylogeny for identification of major lineages and critically considers morphology when adult morphology and sparse information of immature stages alone did not provide enough information for building a robust classification. Reconstruction of the ancestral states of morphological characters on the phylogenetic tree recovered from DNA data presents evidence for multiple origins of the four-costae pattern on the elytra, shortened elytral costa 1, patterns of pronotal areolae and flabellate antennae. As a consequence, revised morphological delineations of the subtribes and genera are proposed: three major lineages are defined as Metriorrhynchina Kleine, 1926, Metanoeina subtrib. nov. and Cautirina subtrib. nov. The subtribes Trichalina Kleine, 1928 and Hemiconderina Bocak & Bocakova, 1990 are synonymized with Metriorrhynchina Kleine, 1926. Metanoeina are studied in detail and three genera are placed in the subtribe: Metanoeus Waterhouse, 1879, Xylometanoeus gen. nov., and Matsudanoeus gen. nov., with Xylometanoeus japonicus (Bourgeois, 1902) comb. nov. and Matsudanoeus yuasai (Nakane, 1969), comb. nov. as type species, respectively. Xylobanus basivittatus Nakane, 1970 is transferred to Xylometanoeus. The concepts of genera Cautires and Xylobanus are based on male and female genitalia. Additionally, the molecular hypothesis is supported by morphology of larvae, when newly proposed Cautirina are characterized by entire tergites in contrast to the longitudinally divided mesoand metathoracic tergites of Metanoeina and Metriorrhynchina. Larval characters support the placement of Xylometanoeus in Metanoeina and the close relationships of Matsudanoeus and Metanoeus. The simultaneous consideration of DNA-based phylogeny and morphology of adults and larvae rejects taxa based on diagnostically usable but strongly homoplastic characters and provides a framework for a robust classification of Metriorrhynchini.