The relationships among the genera of fungus gnats in the mycetophilid subfamily Leiinae are unclear, and the monophyly of this group is questionable. This monograph provides an extensive phylogenetic study of the Leiinae based on morphological data from a large taxonomic sample, including all genera that have ever been assigned to the subfamily and a wide outgroup sampling to properly test subfamilial monophyly. A data matrix with 128 morphological features of 117 terminal taxa was carried out under parsimony using different implicit weight schemes. All recovered topologies support a monophyletic Leiinae that is more restricted than the usual delimitation of the subfamily. We found no consistent evidence that a clade with Docosia Winnertz, Novakia Strobl, Ectrepesthoneura Enderlein, and Tetragoneura Winnertz group together with the remaining genera of Leiinae. A name with subfamily rank-Tetragoneurinae, already present in the literature-is used here to refer to this group. The allactoneurine genera Sticholeia Søli and Allactoneura de Meijere form a clade with the leiine genus Leiella and the genera of Manotinae, which is deeply nested within the Leiinae. The male terminalia patterns found within the subfamily are analyzed and illustrated. A classification for the Leiinae is proposed grouping 33 genera in seven clades ranked as tribes: Selkirkiini Enderlein, Megophthalmidiini, trib. nov., Rondaniellini, trib. nov., Cycloneurini Shaw and Shaw, Manotini Edwards, Anomalomyiini, trib. nov., and Leiini Edwards.A key for the world genera of Leiinae is also provided. The Cretaceous mycetophilid fossil record is revisited and the biogeographic evolution of the Leiinae is discussed.
Tropical forests are among the most biodiverse biomes on the planet. Nevertheless, quantifying the abundance and species richness within megadiverse groups is a significant challenge. We designed a study to address this challenge by documenting the variability of the insect fauna across a vertical canopy gradient in a Central Amazonian tropical forest. Insects were sampled over two weeks using 6-m Gressitt-style Malaise traps set at five heights (0 m–32 m–8 m intervals) on a metal tower in a tropical forest north of Manaus, Brazil. The traps contained 37,778 specimens of 18 orders of insects. Using simulation approaches and nonparametric analyses, we interpreted the abundance and richness of insects along this gradient. Diptera, Hymenoptera, and Coleoptera had their greatest abundance at the ground level, whereas Lepidoptera and Hemiptera were more abundant in the upper levels of the canopy. We identified species of 38 of the 56 families of Diptera, finding that 527 out of 856 species (61.6%) were not sampled at the ground level. Mycetophilidae, Tipulidae, and Phoridae were significantly more diverse and/or abundant at the ground level, while Tachinidae, Dolichopodidae, and Lauxaniidae were more diverse or abundant at upper levels. Our study suggests the need for a careful discussion of strategies of tropical forest conservation based on a much more complete understanding of the three-dimensional distribution of its insect diversity.
Recently a new species of bombyliid fly, Marleyimyia xylocopae, was described by Marshall & Evenhuis (2015) based on two photographs taken during fieldwork in the Republic of South Africa. This species has no preserved holotype. The paper generated some buzz, especially among dipterists, because in most cases photographs taken in the field provide insufficient information for properly diagnosing and documenting species of Diptera.
Most biogeographical studies propose that southern temperate faunal disjunctions are either the result of vicariance of taxa originated in Gondwana or the result of transoceanic dispersal of taxa originated after the breakup of Gondwana. The aim of this paper is to show that this is a false dichotomy. Antarctica retained a mild climate until mid-Cenozoic and had lasting connections, notably with southern South America and Australia. Both taxa originally Gondwanan and taxa secondarily on Gondwanan areas were subjected to tectonicinduced vicariance, and there is no need to invoke ad hoc transoceanic dispersal, even for post-Gondwanan taxa. These different elements with circumantarctic distributions are here called 'allochronic taxa' -taxa presently occupying the same area, but whose presence in that area does not belong to the same time period. This model allows accommodation of conflicting sources of evidence now available for many groups with circumantarctic distributions. The fact that the species from both layers are mixed up in the current biodiversity implies the need to use additional sources of evidence -such as biogeographical, palaeontological, geological and molecular -to discriminate which are the original Gondwanan and which are post-Gondwanan elements in austral landmasses.
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