The phylogeny of the fungus gnat family Mycetophilidae (Diptera) is reconstructed with a focus on the species-rich and taxonomically difficult subfamilies Gnoristinae and Mycomyinae. The multigene phylogenetic analyses are based on five nuclear (18S, 28S, CAD, MCS, ITS2) and four mitochondrial (12S, 16S, COI, CytB) gene markers. The analyses strongly support the monophyly of Mycetophilidae and the subfamilies Manotinae, Sciophilinae, Leiinae, and Mycomyinae, although Gnoristinae is paraphyletic with respect to Mycetophilinae. All the genera and groups of genera included are supported as monophyletic, except for Acomoptera Vockeroth, Boletina Staeger, Dziedzickia Johannsen, Ectrepesthoneura Enderlein, and Neoempheria Osten Sacken. Ancestral character state reconstructions were applied to two morphological features present in Gnoristinae and Mycomyinae (i.e. presence of setae on wing membrane and wing vein R 4 ) in order to assess their evolution. The wing vein R 4 appears as an unstable character, spread throughout different clades. A dated phylogeny of the family Mycetophilidae showed that most of the subfamilies of Mycetophilidae originated and diversified during the Cretaceous. The youngest subfamilies, originated in the Paleogene, appear to be Mycomyinae and Mycetophilinae.

S ykora, V., Garc ıa-V azquez, D., S anchez-Fern andez D. & Ribera, I. (2017). Range expansion and ancestral niche reconstruction in the Mediterranean diving beetle genus Meladema (Coleoptera, Dytiscidae). -Zoologica Scripta, 46, 445-458. Species of the genus Meladema (Dytiscidae, Colymbetinae) are some of the largest macroinvertebrates in the western Palearctic region, being top predators in fishless streams. Two of the three described species, Meladema imbricata (Wollaston, 1871) and Meladema lanio (Fabricius, 1775) are Macaronesian endemics from the Canary Islands and Madeira, respectively, while the third, Meladema coriacea Laporte, 1835, is widely distributed from Morocco and the Iberian Peninsula to Turkey, including the Canary Islands. Previous phylogenetic analysis using only mitochondrial markers revealed the existence of two cryptic lineages within M. coriacea, one restricted to Corsica and the other including the rest of sampled populations. We reconstruct here the evolutionary history of the species of Meladema using a more comprehensive sampling covering its whole geographical range, adding nuclear markers and Bayesian molecular dating. Using environmental niche modelling, we test for possible differences in climatic preferences among lineages and reconstruct their ancestral climatic niche. Our results strongly supported the existence of four monophyletic lineages represented by the three recognized species plus a fourth cryptic lineage with populations of M. coriacea from the Tyrrhenian islands (Corsica, Sardinia and Montecristo). This pattern is not likely to be the result of mitochondrial artefacts due to Wolbachia infection, as all 11 tested individuals were negative for this parasite. Dating analysis placed the origin of Meladema in the Middle Miocene although diversification among extant Meladema lineages started in the early Pleistocene and took place in a relatively short time period. Phylogeographic analysis inferred a continental origin of Meladema, with an independent colonization of the Macaronesian and Mediterranean islands. From the south-western Mediterranean region, the continental M. coriacea expanded its range up to Bulgaria and Turkey in the northern basin and to Tunisia in the southern. Results of niche modelling showed that seasonality is the critical factor in shaping the current distribution of Meladema. Island lineages (M. imbricata, M. lanio and the Tyrrhenian lineage of M. coriacea) occur in sites with low seasonality, within the range of the reconstructed ancestral climatic niche of the genus. On the contrary, continental M. coriacea expanded its range to localities outside the ancestral climatic range of the genus, with a higher seasonality and aridity.

This study summarizes available data on karyotypes of water scavenger beetles (Coleoptera: Hydrophiloidea: Hydrophilidae), based on newly acquired data of 23 genera and 64 species. We combine these data with previously published data, which we review. In total, karyotypes are available for 33 genera and 95 species, covering all subfamilies and tribes. Available data indicate that most groups of the Hydrophilidae are diploid and sexually reproducing, with XY (♂) and XX (♀) sex chromosomes; the Y chromosome is always minute and does not recombine with X during meiosis. Exceptions are known in Anacaena, with parthenogenetic diploid or triploid populations in some species and sex chromosomes fused with autosomes in others. The diploid number of chromosomes is 2n = 18 in the subfamilies Acidocerinae, Chaetarthriinae, Enochrinae and Hydrophilinae. Variations are known in species of Anacaena and Berosus (both usually with 2n = 18) and in Hydrochara and Hydrophilus with an increased number of chromosomes (2n = 30). The number of chromosomes is increased in the subfamily Cylominae (2n = 24–30) and in all subclades of the subfamily Sphaeridiinae (2n = 22–32). We summarize protocols for obtaining chromosome slides used for this study and provide step-by-step guidelines to facilitate future cytogenetic studies.

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Megasternini is the largest group of terrestrial water scavenger beetles (Coleoptera: Hydrophilidae) represented by ca. 600 described species distributed worldwide. The highest species diversity is known from tropical areas of all continents. In this study, we used sequences of eight gene regions (five nuclear and three mitochondrial) to investigate the phylogenetic relationships and historical biogeography of this group, implementing maximum likelihood (ML) and Bayesian topology inference, Bayesian divergence dating, ML‐based ancestral area estimation and Bayesian diversification analyses. Topology analyses reveal two main lineages of Megasternini characterized by the morphology of male genitalia and surrounding sclerites; these lineages are defined here as subtribes Megasternina Mulsant and Oosternina new subtribe. We identify 12 principal clades of Megasternini, three in Oosternina and nine in Megasternina. These clades group the taxa largely by their geographic distribution rather than morphology, indicating a parallel evolution of morphological characters. Genera Cercyon Leach, Oosternum Sharp, Cetiocyon Hansen, Australocyon Hansen and Pelosoma Mulsant were not recovered as monophyletic. Species of Cercyon, the most diverse genus in the tribe, are found in all principal clades in both subtribes. These results suggest a need for the reorganization of generic concepts in the tribe. The historical biogeography analysis reveals a series of parallel intercontinental dispersal events, including the colonization of South America by Australian members of Oosternina ca. 90 million years ago (mya) and at least five dispersal events between Asia and America ca. 63–55 mya via the Beringia land bridge. The timing of the Asia‐America faunal interchange corresponds to the hyperthermal climate of the Late Paleocene and Early Eocene that allowed the expansion of tropical and subtropical biomes towards polar regions. Diversification analyses revealed no effect of intercontinental dispersals on speciation or extinction rates and suggested a possible effect of declining global temperatures in the last 20 million years.