Subgenus Cryobius is one of the most numerous among the megafauna of tundra soils, but studies on its species distribution, taxonomy, and ecology are lacking. Phylogeny and phylogeography reconstructions of insects with taxonomic complexity have become possible using an integrative approach. Here, we report that specimens of Pterostichus (Cryobius) mandibularoides, described from North America, were detected in Eurasia. Thus, this species has a trans-Beringian range with high distributions in North America, as well as a disjunctive part of the range on the northeastern edge of Asia within Chukotka and Wrangel Island. Eight COI haplotypes with closed relationships (1–2 mutation steps) were detected within the whole range, and one 28S rRNA haplotype was detected for Eurasia. Bayesian phylogeny revealed that P. mandibularoides had the most recent common ancestor with sister species P. brevicornis and P. nivalis. Mean genetic distances of both markers were similar and higher between P. mandibularoides and both P. brevicornis and P. nivalis (>5% ± 1.0%) than between the latter species (<4% ± 1.0%). The obtained results change the previous view about brevicornis group stock differentiation within Cryobius in the Arctic and require a revision of the phylogeny and phylogeography of brevicornis group species and Cryobius altogether.

Coleoptera, the largest insect order, appears to be subordinate to Diptera in the extent of colonization of the Arctic environment. Beetles comprise about 13% of the insect fauna of the tundra zone, yet in the high latitudes several of their families retain considerable levels of species diversity and play significant cenotic roles. The present communication reviews the circumpolar beetle fauna of the Arctic. Based on original data, literature sources and museum collections, with the use of extrapolations and analogies, the taxonomic and ecological diversity patterns of the suborders, series and families of Coleoptera are distinguished, the latitude-zonal distribution and the northernmost range limits of the species are analyzed, and their adaptations and cenotic relations are characterized.

The empidoid flies of the Russian Arctic islands and Svalbard Archipelago are revised including families Empididae (4 genera, 32 species), Hybotidae (2 genera, 3 species) and Brachystomatidae (1 genus, 2 species). The following ten new species are described: Empididae—Empis septentrionalis Shamshev & Sinclair sp. nov. (Russia: Wrangel Island); Rhamphomyia (Dasyrhamphomyia) gorodkovi Shamshev, Sinclair & Saigusa sp. nov. (Russia: Chukotka mainland, Wrangel Island, Taymyr, Yakutia; USA: Alaska); R. (D.) mallochi Shamshev, Sinclair & Saigusa sp. nov. (Canada: Yukon; Russia: Chukotka mainland, Kolyuchin and Wrangel Islands; USA: Alaska); R. (Pararhamphomyia) subfilicauda Shamshev & Sinclair sp. nov. (Russia: Wrangel Island); R. (P.) submacrura Shamshev & Sinclair sp. nov. (Russia: Wrangel Island); R. (P.) subtenuiterfilata Shamshev & Sinclair sp. nov. (Russia: Wrangel Island, Yakutia); R. (P.) wrangeli Shamshev & Sinclair sp. nov. (Russia: Wrangel Island); R. sublongiseta Shamshev, Sinclair & Saigusa sp. nov. (Canada: Yukon; Russia: Wrangel Island); one species of Rhamphomyia was retained as unnamed due to insufficient material; Hybotidae—Platypalpus septentrionalis Shamshev & Sinclair sp. nov. (Russia: Wrangel Island), P. subtectifrons Shamshev & Sinclair sp. nov. (Canada: Northwest Territories, Yukon; Russia: Wrangel Island; USA: Alaska). For previously described species a short diagnosis and a habitus photo are provided to enable easier recognition. In addition, a key to the species of Rhamphomyia (Empididae) occurring on the Russia Arctic islands and Svalbard Archipelago is compiled. A lectotype is designated for Rhamphomyia armipes Sack, 1923. The male and the female of R. taimyrensis Frey and R. kaninensis Frey are described for the first time, respectively. Tachypeza sericeipalpis Frey is newly recorded from North America (Canada: Northwest Territories, Nunavut) and first illustration of the male terminalia is provided. Trichoclinocera lapponica (Ringdahl) is recorded for the first time from the territory of Russia.

The geographic patterns of genetic and morphological variability in ground beetles were examined throughout Northern Eurasia and North America using the most abundant circumpolar tundra subspecies, Pterostichus (Cryobius) brevicornis brevicornis (Kirby, 1837), as a model. Phylogenetic structure was assessed on the basis of a Bayesian approach using two DNA markers (partial sequences of the COI and 28S rRNA genes), while phylogeographic patterns and population genetic diversity were estimated using the COI gene only. Morphological patterns were analysed using elliptical Fourier coefficients that were calculated based on the pronotum and male genitalia shape outlines. The subspecies shares 23 COI haplotypes throughout its entire circumpolar range, while eight haplotypes of 28S rRNA were detected in Northern Eurasia. Phylogenetic analysis did not reveal subdivided species lineages with strict geographical imprint. The network, F_ST and uncorrected pairwise divergence analyses showed that the genetic distances between populations increase by longitude from Northeastern Asia to Europe. The genetic variability among the five studied geographical population groups of P. b. brevicornis was relatively high. The MANOVA showed significant regional divergence between local populations in Northern Eurasia based on both morphological markers, but only male genitalia variability was geographically structured. Neither the pronotum shape nor the male genitalia shape aligned with the phylogeographic patterns discovered on the basis of COI sequences. The genetic (COI) marker had more variation within, rather than among, population groups in addition to morphology of pronotum but not male genitalia.