Integrative taxonomy of Nearctic and Palaearctic Aleocharinae: new species, synonymies, and records (Coleoptera, Staphylinidae)

Abstract A long tradition of separate Nearctic and Palaearctic taxonomic studies of the diverse aleocharine rove beetles (Coleoptera: Staphylinidae) has obscured the recognition of Holarctic species and detection of adventive species in both regions. Recently, integrated study of the two regions through detailed morphological comparisons and development of an authoritatively identified DNA barcode reference library has revealed the degree to which these two aleocharine faunas are interconnected, both naturally and through human activity. Here this approach is adopted to recognize new species, reveal Holarctic species, and recognize adventive species in both North America and Europe. The following new species are described: Isoglossatriangularis Klimaszewski, Brunke & Pentinsaari, sp. nov. from British Columbia; Gnypetaimpressicollis Klimaszewski, Brunke & Pentinsaari, sp. nov., from Ontario, Maryland and North Carolina; Aloconotapseudogregaria Klimaszewski, Brunke & Pentinsaari, sp. nov., from Ontario and Virginia; and Philhygrapseudolaevicollis Klimaszewski, Brunke & Pentinsaari, sp. nov. from eastern Canada. Dasygnypetavelata and Philhygraangusticauda are revealed to be Holarctic species, resulting in the following synonymies: Dasygnypetavelata (Erichson, 1839) = Gnypetaminuta Klimaszewski & Webster, 2008, syn. nov. and Philhygraangusticauda (Bernhauer, 1909) = Atheta (Philhygra) pinegensis Muona, 1983, syn. nov. The Nearctic species Hylotaochracea (and genus Hylota), Thecturotatenuissima, and Trichiusarobustula are newly reported from the Palaearctic region as adventive, resulting in the following synonymies: Hylotaochracea Casey, 1906 = Stichoglossa (Dexiogyia) forticornis Strand, 1939, syn. nov.; Thecturotatenuissima Casey, 1893 = Athetamarchii Dodero, 1922, syn. nov.; and Trichiusarobustula Casey, 1893 = T.immigrata Lohse, 1984, syn. nov. The Palaearctic species Amarocharaforticornis, Anomognathuscuspidatus, Oligotapumilio, and Parocyusarubicunda are newly confirmed from the Nearctic region as adventive, resulting in the following synonymies: Parocyusarubicunda (Erichson, 1837) = Chiloporaamericana Casey, 1906, syn. nov. and Anomognathuscuspidatus (Erichson, 1839) = Thecturaamericana Casey, 1893, syn. nov. The genus Dasygnypeta, sensu nov. is newly reported from North America, Paradilacra is newly reported from eastern North America, and Haploglossa is newly reported from Canada, resulting in the following synonymy: Paradilacradensissima (Bernhauer, 1909) = Gnypetasaccharina Klimaszewski & Webster, 2008, syn. nov. Native Cypheawallisi is newly reported from across Canada and C.curtula is removed from the Nearctic fauna. The status of both Gyrophaenaaffinis and Homalotaplana is uncertain but these species are no longer considered to be adventive in North America. Three new combinations are proposed: Dasygnypetabaranowskii (Klimaszewski, 2020) and D.nigrella (LeConte, 1863) (both from Gnypeta) and Mocytascopula (Casey, 1893) (from Acrotona). Dolosota Casey, 1910, syn. nov. (type species Eurypronotascopula Casey), currently a subgenus of Acrotona, is therefore synonymized with Mocyta Mulsant & Rey, 1874. Additionally, four new Canadian records and 18 new provincial and state records are reported.


Introduction
Historically, taxonomic research on the hyperdiverse aleocharine rove beetle (Coleoptera: Staphylinidae) faunas of North America and better-known Europe has been conducted separately, with a few exceptions (e.g., Klimaszewski et al. 1979). More recently, a closer examination of Aleocharinae in these two regions has demonstrated that a number of species are shared between the Nearctic and Palaearctic, either naturally (Holarctic) or through human activity (adventive) (e.g., Muona 1984;Klimaszewski et al. 2007;Klimaszewski et al. in press). The interconnectedness of these assemblages, combined with the sheer diversity of the subfamily, have made it difficult to avoid describing synonyms of taxa from other regions, especially when those taxa have been described in entirely different genera (e.g., Gusarov 2003a). One strategy to broadly address this challenge is the publication of detailed illustrations of habitus and genitalia in comprehensive faunal treatments such as the recently available 'Aleocharinae of Eastern Canada' (Klimaszewski et al. 2018) and 'the Danish Beetle Bank' website (Hansen et al. 2017), the latter an online resource for the Danish beetle fauna. In the past few years, resources such as these have made it possible to efficiently cross-check Nearctic and Palaearctic aleocharines without consulting a comprehensive reference collection for each region.
In combination with careful morphological study, large-scale DNA barcoding (e.g., deWaard et al. 2019) has accelerated the discovery of Holarctic species, and the detection of new adventive species and potential synonyms in the Canadian beetle fauna (e.g., Pentinsaari et al. 2019) by algorithmically flagging potential taxonomic issues and novelties, and connecting authoritatively identified specimens to unidentifiable females, damaged specimens, or other life stages. This integrated taxonomic approach, as applied to Aleocharinae, has already resulted in the detection of adventive species of genera Amischa, Atheta, and Myllaena in North America , and has refined the classification of Holarctic species in Atheta (Klimaszewski et al. in press), Boreophilia (Klimaszewski et al. 2019), and Gnathusa (Klimaszewski et al. in press).
Here we broadly compare morphological and molecular data across the Nearctic and West Palaearctic Aleocharinae in order to better integrate the taxonomic knowledge of these two regions. We describe four new Nearctic species, propose revised generic concepts, report new distributional records, and propose a number of new synonyms that impact our understanding of Holarctic and adventive species.

Materials and methods
Almost all specimens used in this study were dissected and their genitalia were subsequently examined on microslides. The genital structures were dehydrated in absolute ethanol, mounted in Canada balsam on celluloid microslides, and pinned with the specimens from which they originated. The photographs of the entire body and the genital structures were taken using an image processing system (Nikon SMZ 1500 stereoscopic microscope; Nikon Digital Camera DXM 1200F) and processed in Adobe Photoshop. Terminology mainly follows that used by Lohse et al. (1990) and Klimaszewski et al. (2018). The ventral part of the median lobe of the aedeagus is considered to be the part of the bulbus containing the foramen mediale, the entrance of the ductus ejaculatorius, and the adjacent venter (ventral part of the tubus of the median lobe) of the tubus; the opposite side is referred to as the dorsal part.
We have examined all DNA barcode data for Aleocharinae previously generated by a variety of projects in both Europe and North America (e.g., Rulik et al. 2017;Sikes et al. 2017;McClenaghan et al. 2019; and other studies summarized by . Fifty-three barcode sequences, the majority of which are Canadian sequence records originating from various projects coordinated by CBG, are published here for the first time. All sequences were analyzed using the workbench tools of the BOLD platform (http://www.boldsystems.org) after applying filters to exclude those flagged as misidentifications, those with sequence lengths under 100 bp, those with stop codons, and those flagged as contaminated. Sequences were generally visualized as clusters in neighbour-joining trees (using the Taxon ID Tree tool). In addition, BIN Discordance Reports, which compare the taxonomy of the specimen records to their BIN assignments, were used to detect potential misidentifications and synonyms.
All COI barcode sequences in BOLD that fulfill quality criteria (minimum length 500 bp, less than 1% ambiguous bases) are automatically assigned into BIN clusters (Barcode Index Numbers; Ratnasingham and Hebert 2013). In addition, sequences between 300-500 bp can be assigned as members of an existing BIN, but they will not be accepted as founding members of a new BIN. BINs correspond to species at a high accuracy in northern and central European beetles (Hendrich et al. 2015;Pentinsaari et al. 2017), and we treat BINs here as provisional hypothetical species.
The DNA barcode sequences studied here, including both previously unpublished data and the sequences published in earlier studies, have been compiled into a publicly available dataset on BOLD (DS-ALEO2020, https://doi.org/10.5883/DS-ALEO2020) along with collecting data, images of the specimens (if available), and other metadata related to the specimens and sequences. The sequences are also available through Gen-Bank (accessions provided in Suppl. material 1: Table S1).

Taxonomic accounts
Tribe Aleocharini Fleming, 1821  Glen Rouge campground, 43.804, -79.146, marsh scrub along riverside, pitfall trap, 9.VI.2013, BIObus 2013 ;Cambridge,rare Charitable Research Reserve,Preston Flats,43.3908, Diagnosis. Amarochara forticornis may be easily recognized among the other Canadian species of the genus by the distal antennomeres, which are less than twice as wide as long. The species is also unique within the genus by having a distinct basal impression on abdominal tergite VI.
Bionomics. In its native range, A. forticornis occurs in a variety of open and forested habitats, including forests, edges of waterways, grasslands, agricultural fields, and gardens (Assing 2002). It has been mostly collected by pitfall traps in the spring and summer, and then from flood debris in the cooler months of the year (Assing 2002). Assing (2002) suggested that beetles in flood debris were washed from some cryptic, subterranean microhabitat. Canadian specimens were collected in similar ways as in Europe.
Comments. Newly reported as adventive in North America, from several localities in southern and eastern Ontario. It is native to the West Palaearctic and is known from most of Central Europe, Russian Central Territory, Armenia, and Georgia (Newton 2019).
The key to Eastern Canadian Amarochara in Klimaszewski et al. (2018) should be modified as follows

1A
Antennomere 10 only weakly transverse (Fig. 1A) (Fenyes), by the bicolored elytra and fusiform body (Klimaszewski and Ashe 1991). Based on the shape of the spermatheca with its narrow capsule and broadly rounded apex, H. nebulosa may be most closely related to Palaearctic H. marginalis (Gravenhorst) as is suggested by barcode clustering. However,  (Casey) A habitus B median lobe of aedeagus in lateral view (adapted from Klimaszewski and Ashe (1991)) C median lobe of aedeagus in dorsal view (adapted from Klimaszewski and Ashe (1991)) D spermatheca E male tergite VIII F male sternite VIII G female tergite VIII H female sternite VIII. Scale bars: 1 mm (A); 0.2 mm (B-H).
H. nebulosa can be readily distinguished by the pronotum, which is dark and paler only along the margins, while H. marginalis has broad pale areas laterally. Haploglossa nebulosa was compared to Palaearctic H. villosula (Stephens) by Klimaszewski and Ashe (1991;as H. pulla (Gyllenhal)), but the species is quite different externally (much darker, finer pronotal punctation) and the spermatheca of the latter species is of the type with a large, rounded capsule.
Bionomics. All members of Haploglossa are nidicolous, mostly in bird nests but also in mammal and ant nests (summarized by Staniec et al. 2010). Some species with well-known life histories appear to specialize on particular types of host nests, such as birds of prey (H. picipennis (Gyllenhal)) or bank swallows (H. nidicola (Fairmaire)) (Staniec et al. 2010). The genus is very rarely collected in North America. The Nearctic species H. barberi (Fenyes) was collected in long series from bank swallow nests (Klimaszewski and Ashe 1991). One specimen of H. nebulosa has been found in a rodent nest within a hollow tree (Klimaszewski and Ashe 1991) but bird and mammal nests have been poorly sampled in the Nearctic and more collecting is needed to determine the biology of the Nearctic Haploglossa (Brunke and Buffam 2018).
Comments. The genus Haploglossa and H. nebulosa are newly reported from Canada, from a single locality in southern Ontario. The species is also known from Oklahoma and Pennsylvania, United States (Klimaszewski and Ashe 1991).
The key to genera of Oxypodini in Eastern Canada in Klimaszewski et al. (2018) should be modified as follows

Bionomics.
Little is known about the microhabitat preferences of this species, but it likely occurs in in nests or cavities within trees as does H. ochracea (Klimaszewski et al. 2018).
Comments. Hylota ochracea, a widespread Nearctic species (Klimaszewski et al. 2018), is newly reported from the Palaearctic region and had been previously known from Finland, Denmark, Germany, Norway, Sweden, and Switzerland (Lundberg 2006;Schülke and Smetana 2015;Newton 2019) under the synonym Dexiogyia forticornis. Hylota is also a new genus record for the Palaearctic region. Nearctic Hylota ochracea and Palaearctic D. forticornis share a BIN and do not form separate clusters. One of the DNA barcode haplotypes is shared between Finnish and Canadian specimens. Nearctic and Palaearctic populations also have identical male and female genitalia. Based on its specialization on microhabitats in forests, we do not consider H. ochracea to be a naturally occurring Holarctic species. Holarctic beetles are generally those that occur north of the treeline and have crossed treeless Beringia in the last 2.8 Mya (reviewed in Brunke et al. 2020). Hylota ochracea may have been introduced to the Palaearctic region with the nest material of poultry or domestic pigeons, or with another form of decaying plant matter. A similar situation has occurred with the bird nest-associated staphylinid Bisnius palmi (Smetana), which was originally described from Italy but later found to be a native Nearctic species (Smetana 1995).
With the above synonymy, the genus Dexiogyia is now known only from externally similar sister species D. angustiventris (Casey) (Nearctic) and D. corticina (Erichson) (West Palaearctic), plus Afrotropical D. congoensis (Scheerpeltz). As in the former D. forticornis, D. congoensis is probably misplaced due to superficial similarity. Hylota is readily separated from Dexiogyia by the shape of the pronotum, which is strongly convergent anteriad, such that its apical width is subequal to the width of the head. In Dexiogyia, the head is distinctly narrower than the pronotum.

Comments.
In Klimaszewski et al. (2020), Neoisoglossa was incorrectly attributed to Casey but was actually proposed by Klimaszewski and Pelletier (2004), apparently as an unnecessary replacement name for Isoglossa Casey 1893. The previous treatment of these generic names and two other synonyms in the catalog of Gouix and Klimaszewski (2007) is correct and followed here. Blackwelder (1952)  Diagnosis. Isoglossa triangularis can be easily distinguished from all Nearctic species of the Ocalea group of genera by a combination of the strongly transverse and sparsely punctate pronotum, transverse antennomere 4, distinct triangular apex of the median lobe in lateral view (Fig. 5B), and distinct and simple 'walking cane' shape of the spermatheca (Fig. 5D).
Bionomics. The specimens were collected in a Malaise trap on an open field surrounded by mixed forest.
Comments. Based on a combination of small size (< 4.5 mm), superficial, meshed microsculpture, sparse pronotal punctation, with punctures separated by more than two puncture diameters, pronotum transverse, shorter and narrower than elytra, and the transverse antennomeres 5-10, I. triangularis keys to genus Isoglossa Casey in Klimaszewski and Pelletier (2004). However, barcode sequences of this species do not cluster with Isoglossa agnita but rather form a cluster with Gennadota canadensis and the species of Neothetalia which bear a spermatheca with broad, circular loops, similar to those of Gennadota. Isoglossa triangularis has a simple spermatheca with a long straight stem and is not externally similar to these taxa (see above), and the barcode divergence between these species and I. triangularis is 11-12%. It is likely that I. triangularis belongs in a separate genus, but this is outside of the scope of this study. We here place I. triangularis tentatively in Isoglossa as not to disturb the existing morphological diagnoses of the genera and identification keys (e.g., Klimaszewski and Pelletier 2004;Klimaszewski et al. 2020), pending generic revision of the Ocalea group.  Bionomics. In North America, most specimens of this species have been collected from near water, including a sandy creek bank, in a dried streambed and in moss near the splash zone of a waterfall (Klimaszewski et al. 2018). Nearctic populations of this species are only known from female specimens and the species may be parthenogenetic in North America. In its native distribution, the northern and northwestern populations are also parthenogenetic (Assing 2021) and most likely represent the source population for the Nearctic introduction.
Comments. Parocyusa rubicunda is a widespread West Palaearctic species (Europe, European Russia, Turkey, Georgia, Iran, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan) (Assing 2021). It is confirmed as established in the Nearctic region and had been previously known from North America under the synonym Tetralaucopora americana (Casey) (Klimaszewski et al. 2018). Assing (2021) recently reported this species from BC and treated T. americana as a tentative synonym based on the results presented in this paper.
Although all available sequences of this species are partial (382-407 bp) and a BIN has not been established as that would require at least one founding member with a minimum sequence length of 500 bp, Nearctic and Palaearctic sequences form a distinct cluster with only a single variable nucleotide site. External morphology and that of the spermatheca are identical. As spermathecae are of generally poor diagnostic value (especially the distal part) in Parocyusa (Assing 2021), the barcode evidence was quite critical for the resolution of this issue. Based on this evidence and a distribution centered around populated areas in northeastern and western North America, we here consider this species to be adventive in the Nearctic region. At the moment, it is not yet possible to determine whether the population in BC is a separate introduction from the northeastern population.
Recently, Assing (2021) revalidated Parocyusa as a genus separate from Tectusa after the discovery that Tectusa was not a monophyletic group. The type species of Parocyusa was found to be congeneric with that of Tetralaucopora, and the latter became a junior synonym of the former.

Tribe Tachyusini C.G. Thomson
Revised key to the Canadian genera of Tachyusini Adapted from Klimaszewski et al. 2018. 1 Elytra at humerus only slightly broader than pronotum at base ( Abdomen clavate, at base distinctly narrower than head (Fig. 9); tergite III ca. as long as wide or longer; tergal impressions with median carina (Fig. 9)  Bionomics. This species has been collected from various wetland microhabitats including the edges of lakes, rivers, and a beaver pond (Gusarov 2003a).
Comments. Paradilacra densissima and the genus Paradilacra, widespread in western and central North America (Gusarov 2003a), are newly reported from SK (records in Klimaszewski et al. 2016a, as G. saccharina) and eastern North America based on records from NB ) and ON (this study), including one sequenced paratype of synonym Gnypeta saccharina. Under the present concept, only one widespread species of this genus is known.

Dasygnypeta Lohse, 1974, sensu nov.
In his key to the genera of Tachyusini, Paśnik (2010) distinguished Dasygnypeta, with its single Palaearctic species Dasygnypeta velata (Erichson), from the Nearctic genera by the following features: the narrow and slender abdomen with base approximately as wide as head, the 'very deep' tergal impressions, abdominal pubes- cence of tergites III-V directed posteriad, basal segment of metatarsus shorter than following two segments. Through an analysis of barcode data, we have discovered that the recently described Gnypeta minuta Klimaszewski & Webster is a synonym of D. velata (see below). A re-examination of other Nearctic Gnypeta species revealed two others that are closely related to D. velata: G. baranowskii Klimaszewski, and G. nigrella (LeConte). Their morphological divergence from other Gnypeta was represented by an earlier placement in the 'Nigrella species group' of Gnypeta by Klimaszewski et al. (2008), together with G. saccharina (now a synonym of Paradilacra densissima). In corroboration with morphology, DNA barcodes of D. velata and G. nigrella form sister clusters (sequences of G. baranowskii not available). Transfer of these two Gnypeta species to Dasygnypeta required a new concept for this genus as most of the distinguishing features were apomorphies of D. velata or found not to be of diagnostic value due to variability or overlap with other genera. Here we distinguish members of Dasygnypeta by their characteristic abdomen (Figs 10-12): base of abdomen ca. as wide as head; basal half of abdomen elongate, tergite III (first visible) only moderately transverse, ~ 2 × as wide as long (at least 2.5 × in Gnypeta); tergites III-V with very deep basal impressions, each creating strongly convex areas on the disc. Members of Dasygnypeta could be confused with Tachyusa, which also bears an elongate basal abdomen, but in the latter genus tergites III-V are far more elongate and the abdominal base is narrower than the head (Fig. 9). Dasygnypeta nigrella was even originally described by LeConte (1863)  Bionomics. The type series was collected by sifting litter (Klimaszewski et al. 2020).
Comments. We here transfer this species to Dasygnypeta sensu nov. based on morphology illustrated by Klimaszewski et al. (2020). This recently described western species is most similar to eastern D. nigrella based on the moderately elongate antennae, more robust body and the distinctive deep emargination of female sternite VIII. However, it is easily distinguished by the coarser pronotal punctation, and male and female genitalia (Fig. 10). The aedeagus of D. baranowskii is superficially similar to P. densissima but these taxa are externally quite different.   Bionomics. Collected along the edge of a variety of running and standing waterbased habitats.
Comments. We here transfer this species to Dasygnypeta sensu nov. based on morphology and close clustering of DNA barcode sequences with D. velata. Dasygnypeta nigrella is a widespread species in eastern North America and is here newly reported from Manitoba and Quebec. Bionomics. Nearctic specimens have been collected most frequently along the margins of running water but also along the margins of a forest pool (Klimaszewski et al. 2018).
Comments. Dasygnypeta velata is newly reported from North America and was previously known in the Nearctic region under the synonym Gnypeta minuta (Klimaszewski et al. 2018). We here newly record this taxon from MB. Dasygnypeta velata is here considered a Holarctic species as it has a broad, transpalaearctic distribution (Europe to Siberia; Newton 2019), occurs along rivers and has been collected north of the treeline in Alaska.
This species has been collected together with D. nigrella in southern Manitoba (see above). The barcode sequences of the specimens from Alaska are all partial (386 to 407 bp), but the overlapping parts of the sequences are identical to the two German sequences. Etymology. The species epithet refers to the longitudinal impression on the pronotum, most strongly developed in males.
Diagnosis. Gnypeta impressicollis can be easily distinguished from all Nearctic species of the genus (except eastern G. baltifera (LeConte)) by the hexagonal pronotum with a longitudinal impression in the basal half (females) to nearly entire pronotal length (males). Males also have an impression on the vertex of the head. We have examined the female type of G. baltifera and it is externally similar but differs by the shorter, less angulate hexagonal pronotum, reddish and longer elytra and spermatheca with an elongate stem (C-shaped in G. impressicollis).
Description. Body length 3.2-3.4 mm; colour dark brown, elytra brown with irregular rust-brown patches, first two or three basal tergites rust-brown with posterior edge yellow, apex of abdomen rust-brown, legs and antennae rust-brown; integument highly glossy (Fig. 13A); pubescence yellowish grey, moderately long and moderately sparse; all antennomeres distinctly elongate; head round with short neck (visible only when head is distended from thorax), vertex in males with broad central impression, vertex of females with much smaller and narrower median impression, maximum width of head slightly less than maximum width of pronotum; pronotum hexagonal in shape, ca. as long as head, with a longitudinal impression in the basal half (females) to nearly entire pronotal length (males), pubescence on disc directed anteriad along midline and obliquely laterad elsewhere; elytra wider than either head or pronotum, at suture shorter than pronotum along midline, pubescence directed obliquely posteriad forming wavy pattern medially on each side; abdomen arcuate laterally, broadest in apical third, at base distinctly narrower than elytra; legs very long, hind tarsus with basal tarsomere ca. as long as the two following ones combined. MALE. Tergite VIII with apical margin truncate medially and arcuate laterally (Fig. 13E); sternite VIII elongate, narrowed apically, apex truncate medially and oblique laterally (Fig. 13F); median lobe of aedeagus in lateral view with tubus very short, triangular and gradually tapering to narrowly rounded apex, ventral margin broadly curved ventrad in apical half (Fig. 13B); in dorsal view bulbus moderately large and tubus swelled basally and triangular apically (Fig. 13C); internal sac with complex membranous structures (Fig. 13B,C). FEMALE. Tergite VIII broadly arcuate apically (Fig. 13G); sternite VIII rounded apically with very shallow median emargination (Fig. 13H); spermatheca C-shaped, capsule subspherical with broad apical invagination, stem tubular and C-shaped (Fig. 13D).
Distribution. Origin: Nearctic. Canada: ON. United States: MD, NC. Gnypeta impressicollis is probably broadly distributed in eastern North America.
Bionomics. Specimens were collected by sifting leaf litter along a lake margin and by treading pond vegetation.
Comments. It was challenging to place this species in either Gnypeta or Ischnopoda Stephens based on the concepts of Pašnik (2010). The extremely long legs, pronotal shape, C-shaped spermatheca and superficial punctation of the pronotum and abdomen are consistent with at least some Neotropical members of Ischnopoda but the ligula of G. impressicollis is divided to the base, which is considered to be a feature of Gnypeta (Pašnik 2010). The C-shaped spermatheca of Gnypeta impressicollis also bears some similarity to the G. crebrepunctata group of Klimaszewski et al. (2008) but it is rather different in external morphology. We place this species in Gnypeta pending future systematic research. Bionomics. This species is generally found in anthropogenic habitats, including compost, dung, and old hay and grass (Klimaszewski et al. 2018). In Canada, it has been collected in compost and in ocean coastline drift at the top of the littoral zone (Klimaszewski et al. 2018).
Comments. Oligota parva is a cosmopolitan species that is adventive in Canada. Here we newly report it from Ontario.  Diagnosis. Among Canadian species of Oligota, O. pumilio is extremely similar to O. pusillima in the narrow, parallel body (Fig. 15A) and in male and female genitalia (Klimaszewski et al. 2018). However, it can be distinguished by the more abruptly truncate apex of the median lobe in lateral view (Fig. 15B), differently shaped sclerites of the internal sac (Fig. 15B), medially projected apex of male sternite VIII, and the transverse capsule of the spermatheca (Fig. 15C) (Kapp 2019).
Bionomics. This species occurs in a wide variety of habitats across a broad elevational range, including hollow trees, plant debris, old hay in cattle barns, moldy substrates and in mushrooms (Kapp 2019). The barcoded Nearctic specimens were collected from grassland habitats by an intercept trap (Alberta) and a pitfall trap (Montana).
Comments. Oligota pumilio is a West Palaearctic species that is adventive in Canada. Although it has been previously reported from the United States (OH, IL, DC) (Newton 2019), these records need confirmation as they are in the east, some distance away from the present records. This species' presence in North America is thus verified here for the first time, from both Canada (AB) and United States (MT). It has also been reported as adventive from Argentina, Chile, and New Zealand (Newton 2019). The barcoded specimens of O. pumilio from Canada and the United States share the same DNA barcode haplotype, which is also shared by some of the specimens from Germany. Bionomics. This species occurs in a variety of moist to dry, decaying organic matter including rotting hay, compost, hollow trees, and ant nests (Kapp 2019). Canadian specimens were collected in compost (Webster et al. 2016), and in malaise traps and flood debris in a suburban setting (present study).
Comments. Oligota pusillima is a Palaearctic species that has been introduced to North America, South America, Australia, Africa, and southeast Asia (Kapp 2019, Newton 2019. It is here reported from Ontario and Alberta for the first time, the latter representing the westernmost record in North America. Specimens from Alberta  Comments. Anomognathus athabascensis, recently described from Alberta (Klimaszewski et al. 2016b), is newly reported from Manitoba. This native Nearctic species is likely transcontinental but rarely reported due to its small size and elusive habits.  Males and females of the syntype series were morphologically consistent with the specimens forming molecular cluster BOLD:AAO0339, including those sequenced from Ontario, Canada. As the most obvious difference between A. cuspidatus and the potential new Central European species (see Diagnosis) was the shape of the median process on male tergite VIII (in lateral view) (Fig. 18B, D), a male syntype (see above) was designated as the lectotype of this species to fix its identity. Morphology of the aedeagus itself was difficult to study due to its small size and obvious differences between molecular clusters (see below) were not observed (Fig. 19).
Casey (1893) gave numerous characters to distinguish A. americanus from A. cuspidatus but all of these were observed to be highly variable within populations in the material studied, including the shape of apical antennomeres, shape of the pronotum, position of the abdominal tubercles in the male, and the type of dorsal expansion of the median process of male tergite VIII. We could not find the depression at the base of tergite VIII on the holotype of A. americanus mentioned by Casey (1893). Although the aedeagus of the holotype was not studied (not extracted from partly damaged and fragile pygidium), male tergite VIII was intact and its median process in lateral view bears an apical hook, matching the present concept for A. cuspidatus (Fig. 20). Therefore, in corroboration with Fenyes (1918), we treat A. americanus as a synonym of A. cuspidatus.    Smetana, 1963 (11); Nová Sedlica, Smetana, 1961 (2); Ruská Poruba, Smetana, 1956 (2 Diagnosis. Anomognathus cuspidatus is distinctive for its trident-shaped apex of male and female tergite VIII (Fig. 20A-C) and can be distinguished from all described species by this feature alone. However, in the course of this study, specimens representing a remarkably divergent barcode cluster (BOLD:ACA9191; 9.63% uncorrected p-distance to A. cuspidatus) were investigated and found to likely represent an undescribed species of Anomognathus in Europe (confirmed specimens from Finland and Germany). Although most morphological characters of A. cuspidatus and the putative new species are highly variable, including the median lobe of the aedeagus, males can be dependably separated based on the shape of their median process of tergite VIII in lateral view: A. cuspidatus bears a minute to distinct hook at the apex (Fig. 20A-C), while in the undescribed species, the median process converges evenly to a single point, creating an elongate, turnip-shape (Fig. 20D). The shape of tergite VIII in females was observed to be extremely variable and no features were deemed to be diagnostic. Externally, most specimens can be recognized as either species (especially males) by the relative proportions of the head versus the pronotum, with A. cuspidatus generally bearing a small pronotum, narrower than the head (Fig. 18A) and the undescribed species bearing a wider, longer pronotum, wider than the head (Fig. 18C). The limits of this taxon need further investigation and should include morphological study of a much wider range of sequenced material.

Non-type material (sequenced specimens indicated in square brackets). Cana
Distribution. Origin: West Palaearctic (adventive in North America). Canada: AB, NB, ON. United States: NY.
Bionomics. This species occurs under the bark of dead trees. One specimen (NB) was collected from a Lindgren funnel.
Comments. Anomognathus cuspidatus is a widespread West Palaearctic species that is known from Europe, European Russia and Algeria (Newton 2019) and has been previously known in North America under the synonym A. americanus. The record from Beijing, China should be verified. The species has become introduced in North America (before 1893) and it is unclear whether the population in Alberta represents a separate introduction from Europe, a secondary introduction from eastern North America or a broad adventive distribution across Canada.
After the results of the present study, two species of Anomognathus are known to occur in North America: native A. athabascensis Klimaszewski, Hammond & Langor and the adventive A. cuspidatus. These are easily separated by the drastically different shapes of male and female tergites VIII (Figs 17D, 20A-C). Previously, only females of A. cuspidatus (as A. americanus) were available from Canada (Klimaszewski et al. 2016b;Webster et al. 2016). Here we demonstrate that all available Nearctic Anomognathus specimens with a trident-shaped tergite VIII correspond to Palaearctic A. cuspidatus.  The aedeagi of the male paratype (holotype in collection of the California Academy of Sciences) of C. wallisi and holotype of A. vincenti are identical and both differ from that of Palaearctic Cyphea curtula (image by V. Assing) by the broader distal lobe in lateral view, which only slightly extends beyond the distal plate ( Fig. 22A-C). Therefore, we transfer Agaricomorpha vincenti from synonymy with Cyphea curtula to synonymy with Cyphea wallisi.

Cyphea wallisi
Other material (DNA barcoded specimens Bionomics. Specimens have been collected in Malaise traps, window traps and Lindgren funnels placed in forests. Both the closely related West Palaearctic C. curtula and C. latiuscula Sjöberg have been consistently collected under bark, where they occur in the larval burrows of various longhorn beetles (Cerambycidae), bark beetles (Curculionidae: Scolytinae) and the carpenter moth (Cossus L.) (Palm 1968).
Comments. Cyphea wallisi is a broadly distributed native Nearctic species, reported from AB east to NS. Here we treat Nearctic records of Cyphea as C. wallisi (previously treated as Palaearctic C. curtula, e.g., Klimaszewski et al. 2018) and newly report the genus from ON and NS. Cyphea wallisi is probably far more broadly distributed in North America than currently known and has been underreported due to its small size.
Sequenced Nearctic specimens of Cyphea from ON and NS formed a barcode cluster that was nearly 5% divergent from those of Palaearctic specimens of C. curtula (BOLD:AAO1175, one published sequence record from Belgium and three unpublished records from the Netherlands). Northern European C. latiuscula, the only other species of the genus, has a broader body outline, different male genitalia and is quite differently colored (bicolored pronotum and pale elytra). No barcode sequence data are currently available for C. latiuscula. Based on the study of one paratype of C. wallisi, described from Manitoba and not reported since, it was discovered that Nearctic specimens of Cyphea correspond to this species and differ from Palaearctic C. curtula by the broader distal lobe of the median lobe of the aedeagus in lateral view, which only slightly extends beyond the distal plate ( Fig. 22A-C). The shape of the median lobe of the aedeagus in dorsal view may also be diagnostic (Fig. 22D) but a preparation in this view was unavailable for C. curtula. The illustration in Palm (1968) of the aedeagus of C. curtula in dorsal view appears to be less angulate than that of C. wallisi but this needs verification. Based on these differences in male genitalia (Fig. 22A-C) and the COI barcodes, Cyphea wallisi is morphologically and genetically distinct from Palaearctic C. curtula, and the latter species does not occur in North America as far as known. Both of these species have a median tubercle on male tergite VII, mentioned earlier by Fenyes (1921) but this structure was omitted from the illustrations in Klimaszewski et al. (2018), though it was present in the original description of synonym Agaricomorpha vincenti (Webster et al. 2016). Previous differences between the two species given by Klimaszewski et al. (2018) (e.g., projecting pronotal angles, lighter/ darker body) proved to be highly variable.  woud, 50.7505, 4.423, 135 m, 16.VI.2010, F. Koehler (1, ZSM). Finland: Oba: Oulu, Linnanmaa, 65.0633, 25.4712, 7.VI.2011, M. Pentinsaari (1, ZMUO);Obb: Tornio, Kalkkimaa, 65.9014, 24.4711, 10.VII.2012, M. Pentinsaari (1, ZMUO);Al: Lemland, Herrövägen, 59.9796, 20.1954, car net, 5.VII.2012. Germany: Brohl-Luetzing, Brohltal, 50.4727, 7.31272, 22.V.2010, F. Koehler

Comments.
Gyrophaena affinis is newly reported from AB based on barcoded material. Sequenced Nearctic specimens from ON, AB, NB, and QC form a distinct barcode cluster, separate from all sequenced Palearctic specimens and divergent by 4.65%. This pattern is inconsistent with a species that is adventive in North America and we remove G. affinis from the list of adventive species in Canada. In comparing images between those of Nearctic specimens (Fig. 23B) and those of Enushchenko and Semenov (2016) for Palaearctic specimens, there appear to be slight differences in the median lobe of the aedeagus in lateral view. In the Palaearctic illustration, the apex of the median lobe is more acute and its secondary lobe is evenly rounded at apex, while the Nearctic illustration shows a more rounded apex of the median lobe and knob-like apex of the secondary lobe (Fig. 23B). More research is needed to determine the status of the Nearctic and Palaearctic populations, though the level of genetic divergence between discrete Nearctic and Palaearctic populations suggests that two sister species are involved. Bionomics. Specimens have been collected from a partly dried Pleurotus mushroom, from within the pores of a Trametes polypore, and from the nest contents of a Barred owl (Strix varia Barton) (Klimaszewski et al. 2018). The specimen from QC was collected from Polyporus squamosus on a beech tree.

Gyrophaena gracilis Seevers, 1951
Comments. The new record from QC, near the ON border, bridges the wide gap between previous records in NB and WI. Diagnosis. Gyrophaena simulans is extremely similar to G. criddlei and G. pseudocriddlei but has a slightly more transverse and flatter pronotum, with straighter apical and basal margins, and differently shaped upper process of the median lobe in lateral view (Fig. 25B): longer than that of G. pseudocriddlei but shorter and broader than that of G. criddlei. The emargination of male tergite VIII in G. simulans appears to be shallower and broader than that of G. criddlei but more specimens are needed to confirm this.

Gyrophaena simulans
Bionomics. The Canadian specimens were collected by sifting mushrooms in a deciduous forest. No detailed data on the host fungus were recorded.
Comments. Gyrophaena simulans is a native Nearctic species distributed in eastern North America and is newly reported from Canada. The barcode cluster BOLD:ACY8004 also contains specimens identified as related species G. criddlei (female) and G. pseudocriddlei but more research, with broader sampling of sequenced, identified males, is needed to determine whether these species share a BIN or these specimens are misidentified. As we were unable to verify the identifications at this time, these records are not published here. Bionomics. Specimens occur under bark of dead trees. Comments. Sequenced Nearctic specimens from ON form a distinct barcode cluster, separate from all sequenced Palearctic specimens and divergent by 7.58%. This pattern is inconsistent with a species adventive in North America and we remove H. plana from the list of adventive species in Canada. Preliminary comparisons between images of Palaearctic and Nearctic specimens revealed that there may be some slight differences in the shape of the spermatheca. More research is needed to determine the status of the Nearctic and Palaearctic populations, though the level of genetic divergence between discrete Nearctic and Palaearctic populations suggests that two sister species are involved.   Bionomics. Canadian specimens were collected by car-netting in mixedwood forests, while Palaearctic specimens are known from compost and other plant-based debris (Horion 1967).

Comments.
Thecturota tenuissima is native to the Nearctic region and has become accidentally introduced to the West Palaearctic, including the Canary Islands, where it was previously known under the synonym T. marchii (Newton 2019). We expect this species to be broadly distributed in eastern North America and has been overlooked over much of its range because car-netting, an effective method for collecting small, obscure staphylinids, is rarely used in the Nearctic region.
Nearctic and Palaearctic populations do not differ in male and female genitalia or in external morphology. Molecular data were unavailable for the Nearctic population, which was recently reported from Canada (Klimaszewski et al. 2017) but described from Rhode Island, USA in 1893 (Casey 1893). However, we are confident that these species are synonyms. Muona (1984) stated that T. marchii is a 'recent' introduction to Europe but from an unknown source. Thecturota is primarily a New World genus, with ten described species in North and South America (Newton 2019). Thecturota magnifica (Machulka) is currently treated as a synonym of T. marchii (Newton 2019) and we simply transfer this name to synonymy with T. tenuissima. The only Palaearctic species remaining is poorly known T. williamsi (Bernhauer, 1936), known only from the type collected in Great Britain and probably a synonym of T. tenuissima. The characters Bernhauer (1936) gave to separate his species from T. tenuissima (as T. marchii) are slight differences in coloration and body proportions, which are both highly variable in the Palaearctic specimens of T. tenuissima studied. Therefore, we consider T. tenuissima to be a native Nearctic species that has become adventive in the West Palaearctic and suggest that genus Thecturota is naturally restricted to the Nearctic and Neotropical regions.
Etymology. The species epithet refers to the similarity to related species A. gregaria (Erichson), which was originally treated separately from other Aloconota under subgenus Glossola Fowler (e.g., Benick 1954) because it lacks obvious male secondary sexual characters.
Diagnosis. Aloconota pseudogregaria can be easily distinguished from all other species of the genus occurring in eastern North America by the distinctly bicolored abdomen (Fig. 28A). Among Central European species, the spermatheca of A. pseudogregaria is most similar to that of Palaearctic A. gregaria but in the latter the apex is distally truncate, median lobe is distinctly sinuate and only weakly projected ventrad, the abdomen is darker and not distinctly bicolored, and the microsculpture of the forebody is much stronger, creating a dull reflection.
Bionomics. This species has only been collected by passive traps, including malaise and pitfall traps. All specimens have been collected from at least partly disturbed habitats, such as forest edges, agricultural fields, and suburban environments. This species corresponds to 'Aleocharinae sp. 5' in Brunke et al. (2014), which was collected in both soybean fields and adjacent forest edges by pitfall traps.
Comments. Aloconota pseudogregaria is probably broadly distributed in northeastern North America. We have compared the male and female genitalia of A. pseudogregaria with all Central European and Nearctic species of Aloconota, and are confident that this taxon has not been previously described from Europe or North America, despite its occurrence in disturbed habitats in North America, which is typical for introduced species. Although Aloconota pseudogregaria clustered most closely with A. gregaria (BOLD:ABU6164) in our barcode dataset, its BIN is ~ 8% different from that of the latter. Based on morphology of the aedeagus and spermatheca, Aloconota pseudogregaria is probably even more closely related to East Palaearctic Aloconota described from Japan and Korea (e.g., Sawada 1970 [as Tomoglossa], Lee and Ahn 2017) rather than to A. gregaria. However, the described species all differ markedly in external morphology.
Athetini  Atheta ( Bionomics. Canadian specimens have been collected on farmland and directly from horse manure. Comments. Atheta nigra is a Palaearctic species reported from across Europe, European Russia, Kazakhstan, North Korea and southern China (Newton 2019). It is adventive in North America and New Zealand (Newton 2019) and is here newly reported from Ontario. The new record from Ontario indicates that this species is far more widely distributed in North America than previously known. (Casey, 1893), comb. nov. BOLD:ACH8720 Fig. 30A-F Eurypronota scopula Casey, 1893 Pancota laetabilis Casey, 1906 Dolosota abundans  Dolosota flaccida   Diagnosis. Mocyta scopula can be distinguished from bicolored Canadian species and paler specimens of M. fungi by its finely punctate pronotum that is almost as wide as the elytra and ca. as long, and the distinctly transverse antennomeres 6-10 (Fig. 30A). The barcode sequences of M. scopula forms a sister cluster with M. luteola (BOLD:ABW2813), with a sequence divergence of ~ 7.5%. These species can be easily separated using the above diagnosis.

Mocyta scopula
Bionomics. The Canadian specimen was collected from forest litter with a Berlese funnel but nothing specific is known about this species' microhabitat preferences.
Comments. Mocyta scopula is a native Nearctic species distributed in eastern North America. Here we newly report it from Canada based on one male specimen collected in southern Ontario. Its distribution in the United States is based on type material, including its putative synonyms, which should be verified.
Mocyta scopula is the type species of Dolosota Casey, which has been treated as a subgenus of Acrotona since Seevers (1978). However, using the generic concepts of Klimaszewski et al. (2015), this species best fits in genus Mocyta based on the following character states: dorsal surface without fine white pubescence; broad tergite VIII with basal line not touching base of tergite; spermatheca with pear-shaped capsule and distinct but small invagination, and thin and irregularly shaped stem ending in a tightly deflexed apex (Fig. 30F) (based on images taken of female syntypes (NMNH). Further evidence comes from barcode sequences of this species, which cluster with the other species of Mocyta. Therefore, we synonymize Dolosota Casey syn. nov. with Mocyta Mulsant and Rey. The other species included in Dolosota by Seevers (1978) were treated as synonyms of M. scopula by Majka and Sikes (2009), in addition to two other Casey names (see above synonymy), following the unpublished results of a type revision by V. Gusarov (Gusarov 2003b). These synonyms and M. scopula are here comb. nov. in Mocyta.
The aedeagus, coloration and punctation of the Canadian specimen are consistent with type material of M. scopula, previously examined and imaged by JK. The two other members of the BIN BOLD:ACH8720 originate from a study by Elven et al. (2010), and were mined into BOLD from GenBank. They were collected in the USA and identified verbatim as Mocyta scopula by V. Gusarov.
The key to Canadian Mocyta in Klimaszewski et al. (2015) can be modified as follows (bicolored species) 2a Pronotum much broader than elytra; antennal articles 5-10 in specimens slightly elongate; spermatheca forming concentric circles posteriorly . Pronotum finely punctate and transverse, but more rounded at base and apex (Fig. 30A); antennal articles 5-10 distinctly transverse (Fig. 30A); median lobe in lateral view only weakly produced ventrad (Fig. 30B)  Bionomics. As with other species of the genus, P. angusticauda is associated with riparian habitats. Comments. Philhygra angusticauda is a Holarctic species that was previously recognized in the Palaearctic (Finland, Norway, European Russia, Russian Far East) (Schülke and Smetana 2015;Newton 2019) under the synonym P. pinegensis (Muona). We newly report this species from Alberta and suggest that it broadly occurs across northern Canada. Specimens from the Nearctic and Palaearctic were found to have identical genitalia and their DNA barcodes form a cluster with only 0.3% divergence between Finnish and Canadian specimens. Diagnosis. This species can be readily recognized by a combination of its small size, large eyes and relatively simple, ventrally projecting median lobe of the aedeagus in lateral view (Fig. 32B).
Bionomics. Nothing specific is known about this species' microhabitat preferences but it probably occurs near water as do other species of the genus. The series of Ontario specimens was collected using a car net, which is typically effective for collecting small staphylinids.
Comments. Philhygra finitima is a native Nearctic species distributed in northeastern North America. Here, we newly report it from Canada. Canadian specimens were identified based on comparison with images ( Fig. 32C) of the unpublished lectotype of P. finitima in the Casey collection at NMNH. Diagnosis. Philhygra laevicollis can be distinguished from most species of the genus by the general shape of the median lobe in lateral view. It is most similar to P. pseudolaevicollis but has a sinuate ventral face of the median lobe in lateral view and large spines in the internal sac (Fig. 33B).
Bionomics. Specimens have been collected from clear cut areas, transitional zone of a coniferous forest, seepages, and river and creek edges, from moss, leaf litter, gravel, dung, carrion and pitfall traps (Klimaszewski et al. 2020).
Comments. Philhygra laevicollis is a western Nearctic species that was previously considered to include eastern populations that we here treat as Philhygra pseudolaevicollis sp. nov. that differs in male genitalia but also by the divergent DNA barcode sequence. Neither this species nor P. laevicollis are known from MB, this error was corrected by Klimaszewski et al. (2020). We have observed some variation in the shape of the sclerotized structure present on the female pygidium between specimens collected in BC, but it is not yet clear whether additional species are overlooked within the present concept of P. laevicollis.  This species was reported from Canada (Manitoba) for the first time in the checklist by Bousquet et al. (2013) but no specimens could be found in the CNC to support this record. It is likely that the species P. tenuicula (Casey, 1911) described from Manitoba and treated as a synonym of P. palustris (Newton 2019), is the basis of this record.
Philhygra palustris was first recorded from North America by Muona (1984) from New York, Maine and Pennsylvania but detailed specimen level data were not provided. Several specimens from various localities in southern Ontario have been sequenced, and their barcodes cluster with European specimens, with multiple haplotypes shared between Canada and Europe. This common European species is here confirmed to be adventive in Canada and is probably broadly distributed in at least eastern North America. Description. Body narrowly subparallel, moderately flattened, length 3.0-4.2 mm; colour dark brown, elytra dark brownish to brownish yellow, except for darker scutellar area and paler legs, basal antennomeres rust-brown (Fig. 35A); integument moderately glossy, forebody sparsely punctate and pubescent, with pubescence long, punctation fine, microsculpture distinct and consisting of round and slightly convex meshes; head slightly elongate, round, ca. as wide as pronotum, eyes as long as genae in dorsal view, postocular carina strong basally, diffuse apically; antennae slender, at least as long as pronotum and elytra combined, antennomeres 1-3 strongly elongate, 6 and 7 slightly elongate, 8 and 9 slightly elongate or subquadrate, and terminal one as long as two preceding antennomeres combined; pronotum slightly transverse, impressed medially, arcuate laterally and basally, pubescence sparse, hypomeron visible almost for entire length of pronotum; elytra transverse, broader than pronotum; abdomen subparallel. MALE. Tergite VIII slightly transverse, arcuate apically (Fig. 35D); sternite VIII highly elongate, rounded apically and with wide distance between antecostal suture and base of disc (Fig. 35E); median lobe of aedeagus with moderate-sized bulbus, tubus short, ventral margin arcuate basally and straight apically, tubus narrowly triangular at apex in lateral view (Fig. 35B); internal sac sclerites without spike-like projections, complex as illustrated (Fig. 35B); in dorsal view bulbus roughly oval, tubus short, triangular apically. FEMALE. Tergite VIII transverse and truncate apically (Fig. 35F); sternite VIII rounded apically, apex slightly produced, distance between antecostal suture and base of disc wide (Fig. 35G); pygidium as illustrated, with weakly sclerotized central plate, slightly broader than in P. laevicollis (Fig. 35C); spermatheca not illustrated, minute with short sac-shaped capsule without apical invagination and with short narrow stem.
Bionomics. This species has been recorded from various wetland and riparian habitats in NB: in moss and leaf litter near brook and in litter, grasses, and moss on hummocks in old-growth eastern white cedar swamps and a wet alder swamp, in moist leaves along vernal pond margins in various mixed forests, and a red oak/red maple forest; also from pitfall traps in regenerating red spruce forests (NB) and from vernal pool litter in ON (summarized by Klimaszewski et al. 2018). Collecting period: IV-V, VIII. Collecting method: sifting leaf litter, grasses, and moss, under bark (probably overwintering).
Comments. Although they were not re-examined here, the specimens reported by Majka and Klimaszewski (2008) as P. laevicollis, certainly belong to P. pseudolaevicollis. This species is very similar externally and genitally to P. laevicollis occurring in western North America (AK, AB, BC, WA). Previously, it was tentatively identified as P. laevicollis pending additional study (e.g., Klimaszewski et al. 2005;Klimaszewski et al. 2020). The present evidence from DNA barcodes (8.5% divergence between the eastern and western specimens) and morphology of the aedeagus revealed that eastern and western populations represent two distinct, cryptic species. The single barcoded specimen of P. pseudolaevicollis produced a 407 bp sequence and therefore, no BIN has been generated.  Material (DNA-barcoded specimens). Austria: Innervillgraten, Arntal, 46.8362, 12.3348, mountain forest and alpine pastures, car net, 25.VIII.2013, GBOL-Team ZFMK (1, ZFMK). Germany: Nuernberg, N Flughafen, 49.5006, 11.0789, sifting