Arctic terrestrial invertebrate biodiversity is generally poorly known, but the archipelago of Svalbard has one of the most up-to-date inventories of its terrestrial and freshwater faunas of any Arctic region, offering a baseline for long term monitoring of invertebrate communities in space and time. Since the most recent review of the Svalbard invertebrate fauna was produced in 2014, knowledge of this fauna has developed and this inventory is here critically revised and updated. Our aims are (1) to critically review the inventory based on current taxonomic knowledge, (2) publish the complete species inventory, including cross-referencing to the relevant publications, in an open access data archive (GBIF), and (3) highlight the particular advantages that working in Svalbard may bring for scientists working on terrestrial, freshwater, and cryospheric environments. The inventory contains a total 1091 valid species names or interim names. A gap analysis in the Barcode of Life Data Systems reveals that 50% of the species currently documented from Svalbard lack COI (Cytochrome c oxidase subunit 1) barcode reference sequences in this database. Gaps in our knowledge of the Svalbard fauna and how these may be resolved are discussed.

In the NHMO zoological collections, specimens from the Arctic include about 9,000 mammals and 7,100 birds, whereas the Insect Collection holds about 105,000 specimens plus more than hundred jars with unsorted material. The Fish Collection contains approximately 1,400 specimens, while the Herptile Collection (amphibians & reptiles) holds only thirty-one specimens of three taxa. Many of these specimens originate from expeditions to E Greenland, N Canada, Svalbard, Novaya Zemlya, Finnmark, and NE Siberia in the period 1898 to 1966. Furthermore, the DNA Bank has about 5,600 tissue and extracted DNA samples, mostly sampled from wild animals during the last decades but also from specimens in the voucher collections. Most of the Arctic specimens have been digitized and are available in online data portals like GBIF, except for the Insect Collection, where only the type material and about 30 percent of the total specimens are digitized.

In this study, we use low‐coverage shotgun sequencing of genomic DNA, commonly referred to as genome skimming, to investigate the phylogenetic relationships of the fungus gnat genus Allodia Winnertz (Mycetophilidae, Mycetophilinae, Exechiini). Nineteen specimens, representing 16 in‐group and three outgroup taxa, were successfully sequenced and molecular markers of both mitochondrial and nuclear origin were retrieved. The phylogenetic analyses of 13 protein‐coding mitochondrial genes, two ribosomal mitochondrial genes and the nuclear ribosomal 18S and 28S strongly support the monophyly of its two subgenera Allodia s.s. and Brachycampta . Complete mitochondrial genomes of 15 species were assembled, which enables further comparisons with the mitochondrial genomes of other Diptera. Overall, the methodology used in this study proved successful and promising for other dipteran groups. In addition to the phylogenetic reconstruction, the morphological characters previously used to separate the two subgenera were evaluated and re‐examined. Together with the composite structure of the male genitalia, we consider details of the scutal bristles appropriate for separating the two groups. Based on the achieved results, we reinstate Brachycampta stat. rev. as a separate genus.