Review of Canadian species of the genus Mocyta Mulsant & Rey (Coleoptera, Staphylinidae, Aleocharinae), with the description of a new species and a new synonymy

Abstract Six species of the genus Mocyta Mulsant & Rey are reported from Canada: Mocyta amblystegii (Brundin), Mocyta breviuscula (Mäklin), Mocyta discreta (Casey), Mocyta fungi (Gravenhorst), Mocyta luteola (Erichson), and Mocyta sphagnorum Klimaszewski & Webster, sp. n. New provincial and state records include: Mocyta breviuscula – Saskatchewan and Oregon; Mocyta discreta – Quebec, Ontario and Saskatchewan; Mocyta luteola – New Brunswick, Quebec, Ontario, Massachusetts and Minnesota; and Mocyta fungi – Saskatchewan. Mocyta sphagnorum is described from eastern Canada from specimens captured in Newfoundland, New Brunswick, Quebec and Ontario. Mocyta negligens Mulsant and Rey, a native European species suspected of occurring in Canada, is excluded from the Nearctic fauna based on comparison of European types with similarly coloured Canadian specimens, which are now identified as Mocyta luteola. The European species, Mocyta gilvicollis (Scheerpeltz), is synonymized with another European nominal species, Mocyta negligens, based on examination of type material of the two species. Lectotypes are designated for Eurypronota discreta Casey, Atheta gilvicollis Scheerpeltz, Homalota luteola Erichson, Colpodota negligens Mulsant and Rey, Acrotona prudens Casey and Dolosota redundans Casey. The latter species is here synonymized with Mocyta luteola. A review of the six Nearctic species is provided, including keys to species and closely related genera, colour habitus images, images of genitalia, biological information and maps of their distributions in Canada.


Introduction
There has been considerable confusion about the taxonomic status of the genus Mocyta Mulsant & Rey, 1874. Species have historically been assigned to many genera including Atheta Thomson, 1858, Acrotona Thomson, 1859, Colpodota Mulsant & Rey, 1873, Dolosota Casey, 1910, Eurypronota Casey, 1894, and Homalota Mannerheim, 1830. Seevers (1978 included Mocyta fungi, and other groups with the pronotal hypomeron strongly deflexed and not visible in lateral view, within the genus Acrotona. Casey (1894Casey ( , 1910 did not formally recognize Mocyta as a distinct genus and described several species of Mocyta and Acrotona in the genera Eurypronota Casey and Dolosota Casey. Lohse and Smetana (1985) examined types of Homalota breviuscula Mäklin from Sitka, Alaska and assigned the species to Mocyta as a subgenus of Atheta. This species was later recorded as Mocyta breviuscula from eastern Canada by Klimaszewski et al. (2005Klimaszewski et al. ( , 2007aKlimaszewski et al. ( , 2008, Webster et al. (2009), and Majka and Klimaszewski (2010). Lohse et al. (1990) recognized Mocyta as a distinct genus and reported M. amblystegii (Brundin) for the first time from northwestern North America, confirming it as a holarctic species. An adventive Palaearctic species, M. fungi (Gravenhorst), is now broadly distributed in Canada and the USA (Muona 1984, Gusarov 2003, McLean et al. 2009, Klimaszewski et al. 2011, 2013. We believe that species of Mocyta constitute a monophyletic evolutionary lineage defined by the shape of the spermatheca, antennal and pronotal structure, and pubescence and punctation patterns. The genus is externally similar to Acrotona, Strigota and Atheta, sharing with the two former genera a strongly deflexed hypomeron on the pronotum, which is not visible in lateral view. Molecular studies by Elven et al. (2012) clearly treat Mocyta as a taxon of generic rank within the clade of Athetini. The purpose of this paper is to review all Canadian species of Mocyta and to provide modern tools and illustrations for their proper identification. Mocyta species are often abundant in forest litter samples and may be used as indicators of forest health.

Material and methods
Approximately 1000 adults of the genus Mocyta from Canada were studied, and most specimens were dissected to examine the genitalic structures that were dehydrated in absolute alcohol, mounted in Canada balsam on celluloid microslides, and pinned with the specimens from which they originated. Images of the entire body and the genital structures were taken using an image processing system (Nikon SMZ 1500 stereoscopic microscope; Nikon Digit-like Camera DXM 1200F, and Adobe Photoshop software).

Distribution
Each species is cited with its currently known distribution in Canada and USA. Data for distribution map (Canada only) were extracted from specimens in collections. Geographic coordinates were standardized using the NAD83 datum, and maps projected onto a Lambert Conic Conformal using ESRI ArcMap version 10 for Windows. The following abbreviations are used in the text for Canadian provinces and territories: AB -Alberta, BC -British Columbia, LB -Labrador, MB -Manitoba, NB -New Brunswick, NF -Newfoundland (island), NS -Nova Scotia, NT -Northwest Territories, NU -Nunavut, ON -Ontario, PE -Prince Edward Island, QC -Quebec, SK -Saskatchewan, YT -Yukon Territory.
USA state abbreviations follow those of the USA Postal Service.

Key distinguishing Mocyta, Acrotona and Strigota
[Canadian genera with pronotal hypomeron not visible in lateral view] 1 Antennae thick, articles V-X more or less transverse (Fig. 1a); body narrowly elongate, densely punctate, particularly on abdomen, dorsal surface with fine white pilose pubescence (Fig. 1a); pronotum approximately as broad as maximum width of elytra (Fig. 1a); tergite VIII in both sexes with the basal line (antecostal suture) joining the base of tergite (Figs 1d, g), and not the sides of the disc as in other aleocharines; apical margin of female sternite VIII with row of strong microsetae on its dorsal side (Fig. 1h)  3a-8a, e); pronotum broad and shield-shaped, often broader than maximum width of elytra, pubescence moderately dense and directed straight posteriad or obliquely posterolaterad from midline of disc (Figs 3a-8a, e); abdomen gradually narrowed apically and broadly rounded posteriorly; spermatheca with capsule hemispherical or elongate and sac-shaped with usually small apical invagination and short neck, stem thin and regularly or irregularly coiled posteriorly (Figs 3g,h,4f,7e,8f Antennae normally developed and not appearing very thin, usually not strongly contrasting in colour with head (Fig. 2a); pronotum subquadrate to transverse, approximately as wide as elytra, pubescence usually very dense and directed lateroposteriad from midline of disc (Fig. 2a); abdomen tapering apically and often slightly pointed; spermatheca differently shaped, capsule more or less spherical and extended to elongate neck, stem broader than that in Mocyta, regularly coiled posteriorly and often with swelled apex (Fig. 2f) .......Acrotona Thomson

Mocyta Mulsant & Rey, 1874
For synonymy, see Gusarov 2003, Lohse et al. 1990, Smetana 2004 Diagnosis. Mocyta may be distinguished from the other genera of Canadian Aleocharinae except for Acrotona Thomson and Strigota Casey, by having the pronotal hypomeron not visible in lateral view. From Acrotona and Strigota, as well as other aleocharine genera, it may be distinguished by the following combination of characters: antennae very thin and pale, in most specimens contrasting with body colour (Figs 3a-7a); pronotum glossy, moderately convex, broad and shield-shaped, widest at or near middle, with pubescence directed posteriad in midline or entire central section of disc ( Fig. 6a) and posterolaterad at sides, pronotum is at least as broad as the base of the elytra but in most specimens broader ( The shape of the spermatheca in Acrotona is different, with a capsule more or less spherical and extended to a broad and long neck, often pitcher-shaped, and a stem that is broader than that in Mocyta, regularly coiled posteriorly and often with a swelled apex (Fig. 2f). Strigota may be easily distinguished from Mocyta and Acrotona by the basal line of the abdominal tergum VIII laterally joining the base of the tergum in both sexes (Figs 1d,g), while in other athetines the basal line is separated from the tergite base (Figs 3e, i). For illustrations, see also Gusarov (2003).

1
Body bicoloured, head and at least posterior part of abdomen brown to almost black, and remainder of the body reddish to yellowish-brown, pronotum in most specimens paler than the rest of the body, in some specimens elytra mottled with small and irregular in shape darker spots ( Pronotum approximately as broad as elytra (
Diagnosis. Body narrowly oval (Fig. 3a), length 2.5-3.0 mm; uniformly brown to black, appendages light brown (Fig. 3a); antennal articles I-IV elongate and V-X subquadrate or slightly transverse (Fig. 3a); pronotum broad, strongly transverse, rounded laterally and arcuate basally; elytra transverse and at least as long as pronotum; broadly arcuate laterally. MALE: median lobe of aedeagus as illustrated (Figs 3b-d); tergite VIII truncate apically (Fig. 3e); sternite VIII produced apically, with numerous macrosetae and with a broad space between base of disc and antecostal suture, the suture nearly straight or slightly sinuate (Fig. 3f). FEMALE: spermatheca with capsule sac-shaped, as illustrated (Figs 3g, h); tergite and sternite VIII truncate apically (Figs 3i, j). Adults are externally similar to those of M. fungi and may be identified with certainty by the pear-shaped capsule of spermatheca. The presence of males in Canadian populations of M. amblystegii and lack of males in Canadian populations of M. fungi may also aid in identification of this species.
Distribution. Mocyta amblystegii is, according to Lohse (Lohse et al. 1990), a holarctic species recorded in North America from Alaska, Northwest Territories, Yukon and northern Manitoba (Lohse et al. 1990). In Europe, it is recorded from Finland, Norway, and Sweden (Smetana 2004).
Natural history. Adults were found under leaf litter and in moss (Lohse et al. 1990). Diagnosis. Body narrowly oval (Fig. 4a), length 2.4-3.0 mm; body uniformly dark brown to almost black and often with reddish tinge, appendages yellowish to reddishbrown; antennal articles I-IV elongate and V-X subquadrate; pronotum transverse, arcuate laterally and arcuate basally; elytra transverse and nearly as long as pronotum; abdomen broadly arcuate laterally. MALE: Median lobe of aedeagus as illustrated (Figs 4b, c); tergite VIII truncate apically (Fig. 4d); sternite VIII slightly produced apically with broad space between base of the disc and antecostal suture, the suture more or less sinuate (Fig. 4e). FEMALE: spermatheca with capsule pitcher-shaped and flat apically with elongate apical invagination, stem broadly coiled posteriorly (Fig. 4f); tergite and sternite VIII truncate apically (Figs 4g, h). The combination of uniform body colour, elytra no longer than pronotum, distinct shape of spermatheca with deep capsular invagination, and shape of male sternite VIII with broad space between base of disc and antecostal suture, can distinguish M. breviuscula from the remaining Nearctic congeners.

Mocyta breviuscula (Mäklin)
Distribution. Mocyta breviuscula is a native Canadian species distributed transcontinentally in northern Canada, and it was also reported from Alaska, California and Nevada (Lohse and Smetana 1985, Lohse et al. 1990, Gusarov 2003, Webster et al. 2009, Klimaszewski et al. 2005, 2007b, 2011, Majka and Klimaszewski 2008, Brunke et al. 2012. We include new records of this species from Saskatchewan and Oregon (see below for new distribution localities).
Natural history. In Newfoundland, adults were frequently caught in pitfall traps in various forest types (birch, spruce-lichen, spruce-poplar, fir), in vegetation on coastal sand dunes, on shrubby limestone barrens and in disturbed fields amongst grass and weeds (Klimaszewski et al. 2011). The activity period is June to September. Adults were captured in pitfall traps from June to August in yellow birch/balsam fir forest in southern Quebec and in sphagnun and litter in an eastern white cedar swamp in New Brunswick (Klimaszewski et al. 2005, 2007b, Webster et al. 2009 Diagnosis. Body broadly oval (Fig. 5a), length 2.4-3.0 mm; body uniformly dark brown to black, in some specimens body black and posterior or central part of elytra with reddish tinge, appendages light brown; antennal articles I-IV elongate and V-X subquadrate or slightly transverse; pronotum broad, transverse, rounded laterally and arcuate basally; elytra transverse and ca. as long as pronotum or longer; abdomen broadly arcuate laterally (Fig. 5a). MALE: median lobe of aedeagus as illustrated (Figs 5b,c) [absent in North America]. FEMALE: spermatheca with capsule pear-shaped, as illustrated (Figs 5d-h); tergite VIII truncate apically (Fig. 5i); sternite VII broadly rounded apically with fringe of microsetae, distance between antecostal suture and base of disc narrow, antecostal suture sinuate (Fig. 5j). This species is externally very similar to M. amblystegii and may be identified with certainty only by the shape of the spermatheca. The presence of males in Canadian populations of M. amblystegii and lack of males in Canadian populations of M. fungi may also aid in the identification of these species.
Distribution. Palaearctic, adventive in North America, cosmopolitan in many regions of the world (Smetana 2004). Canada: YT, NU, BC, AB, SK, ON, QC, NB, NS, PE, LB, NF, and USA: AK, ME, MA, MN, NY, OR, RI (Moore and Legner 1975, Muona 1984, Gusarov 2003, Klimaszewski et al. 2005, 2007a, 2011, Majka and Klimaszewski 2008, 2010, Brunke et al. 2012. We include new records of this species from Saskatchewan in Canada. Natural history. Mocyta fungi is represented in North America by parthenogenetic females only. In Newfoundland, adults were collected in pitfall traps in cut and burned balsam fir, birch, spruce-poplar and riparian forests, in agricultural fields and amongst vegetation on coastal sand dunes (Klimaszewski et al. 2011). The adult activity period in Newfoundland is June to September. Adults were captured by pitfall traps from May to September in forest litter in mixed wood, red spruce in New Brunswick and yellow birch forest in southern Quebec (Klimaszewski et al. 2005, Majka andKlimaszewski 2010).

II. Mocyta luteola species group
Diagnosis. Pronotum strongly transverse, 1.5 times broader than long, sides arcuate, pubescence directed posteriad in midline and central part of the disc (Fig. 6a); elytra approximately as wide as pronotum (Fig. 6a); spermatheca and median lobe of aedeagus as illustrated (Figs 6b, e-g). Diagnosis. Body narrowly elongate (Fig. 6a), length 1.8-2.6 mm; head and posterior part of abdomen from brown to almost black, pronotum and basal half of abdomen light yellowish-brown to reddish brown, elytra yellowish to reddish-brown with some irregular small dark brown spots; legs and palps yellowish-brown and antennae either uniformly yellowish or basal articles I-IV yellowish and apical ones light brown; antennal articles I-IV elongate and V-X subquadrate to slightly transverse; pronotum short, transverse, strongly rounded laterally, and arcuate basally (Fig. 6a); elytra ca. as long as pronotum (Fig. 6a); abdomen broadly arcuate laterally. MALE: median lobe of aedeagus as illustrated (Fig. 6b); tergite VIII truncate apically, distance between base of disc and antecostal suture moderate in width, suture slightly sinuate medially (Fig.  6c); sternite VIII rounded apically (Fig. 6d). FEMALE: spermatheca with capsule small, pear-shaped and with shallow invagination, stem thin and twisted posteriorly, twists are irregular in shape or forming more or less regular coils (Figs 6e-g); tergite VIII truncate apically (Fig. 6h); sternite VIII broadly rounded apically with apical fringe of short microsetae, distance between base of disc and antecostal suture narrow, suture strongly sinuate medially (Fig. 6i).

Mocyta luteola (Erichson)
Distribution. This native Nearctic species is reported in Canada for the first time from New Brunswick, Quebec, and Ontario (Map 1). In the USA, new records are provided for Massachusetts and Minnesota, and an additional record is provided for New York. The species was previously reported from Indiana, Michigan, New York and Wisconsin (Erichson 1839, Casey 1910, Bland 1865, Blatchley 1910, Moore and Legner 1975. Natural history. Most adults from Quebec were collected in yellow birch and balsam fir dominated forest using pitfall traps (Klimaszewski et al. 2007b). In New Brunswick, adults were found: under decaying seaweed on sea beach; under driftwood on a riverbank; in grass, moss and leaf litter near water in alder and cedar swamps and Carex marshes; in Spagnum moss and leaf litter in a young regenerating mixedwood forest; and in other decaying material in forests. In Ontario, adults were captured in litter around raspberry bushes near a bog, in a Typha marsh, and in a nest of Microtus pennsylvanicus. Adults were active from March to October in Canada. In Minnesota, adults were captured on a lakeshore and in a Microtus nest, and in Indiana were taken by sifting dump vegetable debris from March to November (Blatchley 1910  Comments. In new material of Mocyta from Quebec and New Brunswick, we discovered an unrecorded bicoloured species from Canada that was similar in body size, coloration and shape of spermatheca to the native Mocyta luteola (Erichson) and the European Mocyta negligens (Mulsant & Rey) and Mocyta gilvicollis (Scheerpeltz). After examining the types and additional specimens of the two European species and Mocyta luteola and comparing them with Canadian individuals of our new species, we have concluded that our populations represent Mocyta luteola and that they are not conspecific with the two European species, as they differ in external morphological features such as body proportions, microsculpture, and shape and pubescence of pronotum. After examining the types of both nominal species (M. negligens, M. gilvicollis), and additional specimens from Europe, we found no significant morphological differences between the two species. Therefore these two European species are considered as conspecific, and M. gilvicollis is considered as a new synonym of M. negligens with details listed below (Figs 9a-g, 10-14). Mulsant and Rey 1873: 156 (Figs 10-14); Benick and Lohse 1974 (as Mocyta) ;Smetana 2004 (as Acrotona).

Colpodota negligens
LECTOTYPE (male): the specimen does not have any original label but it is from the historical Rey collection (CCL) and it is pinned next to the original name label by Rey. It bears V. Gusarov's lectotype designation label (2000), and his identification label as Atheta fungi (Gravenhorst), 2000. Because this designation was never published, we formally designate this specimen as a lectotype and put our determination label as Mocyta negligens (Mulsant and Rey), J. Klimaszewski 2014.
PARALECTOTYPES: there are 4 syntypes (1 male, 3 females) in Rey's collection that are here designated as paralectotypes. One of the syntypes (female) bears a black dot label, which indicates that the specimen was taken in Provence, in southeast France. The specimens bear Paralectotype designation labels by V. Gusarov (2000) but because these designations were not published, we formally designate them as paralectotypes. All are determined as Mocyta negligens (Mulsant and Rey), det. J. Klimaszewski 2014. Scheerpeltz 1949: 355 (Figs 9a-g

Mocyta discreta (Casey) Figs 7a-g, Map 2
Eurypronota discreta Casey 1894Casey [1893: 335; Moore and Legner 1975: 359 (as Acrotona Diagnosis. Body broadly oval (Fig. 7a), length 2.4-2.8 mm; head and entire abdomen or its basal part only from brown to almost black, pronotum and basal half of abdomen in most specimens light brown, testaceous or reddish-brown, elytra yellowish to reddishbrown with some irregular small dark brown spots and darker than pronotum, legs and palps yellowish to reddish-brown and antennae either uniformly yellowish to light brown; antennal articles I-IV elongate and V-X variable in length from subquadrate to slightly elongate (Fig. 7a); pronotum transverse, usually very large but variable in width, from slightly broader than elytra to 1/7 wider [pronotum usually broader in females than in males], strongly rounded laterally, and arcuate basally; elytra transverse and shorter than pronotum; abdomen broadly arcuate laterally and with very strong macrosetae apically. MALE: median lobe of aedeagus as illustrated (Fig. 7b); tergite VIII truncate apically (Fig. 7c); sternite VIII slightly produced and rounded apically and with numerous strong macrosetae in apical part of disc, space between base of disc and antecostal suture broad, antecostal suture sinuate medially (Fig. 7d). FEMALE: spermatheca pear-shaped with small and shallow apical invagination, stem thin and straight anteriorly and coiled posteriorly (Fig. 7e); tergite and sternite VIII truncate apically (Fig. 7f, g). This species is readily recognisable from other Mocyta species by its bicoloured body, large pronotum, very strong macrosetae on the apical part of the abdomen, and antennal articles V-X subquadrate to elongate.
Distribution. This nearctic species is newly reported from Canada and the provinces of Ontario, Quebec and Saskatchewan (Map 2), and from Minnesota. Casey (1894) described this species from Cedar Rapids, Iowa, USA, and no other records of this species were published from North America until now.
Natural history. In Ontario, adults were collected in forest litter, deciduous leaf mold, and maple forest from March through October. In Quebec, adults were found in maple-oak forest litter and other deciduous tree litter, from May through August. In Saskatchewan, adults were collected from deciduous forest litter in October.
Etymology. The specific name sphagnorum is an adjective, which derives from the generic name of Sphagnum, in the genitive plural, meaning "of the Sphagnum plant", a dominant plant of the habitat where the species was found.
Diagnosis. Body narrowly oval (Fig. 8a), length 2.4-2.7 mm; uniformly brown to almost black, legs and palps yellowish to reddish-brown and antennae uniformly light brown to brown; antennal articles I-IV elongate and V-X variable in length from subquadrate to slightly transverse (Figs 8a, e); pronotum transverse, variable in width, from slightly-to-distinctly broader than elytra [pronotum usually broader in females than in males, Fig. 8e], strongly rounded laterally, and arcuate basally; elytra transverse and slightly shorter than pronotum; abdomen broadly arcuate laterally and with strong macrosetae apically. MALE: median lobe of aedeagus as illustrated with distinct apical structures of median lobe (Fig. 8b); tergite VIII truncate apically (Fig. 8c); sternite VIII slightly produced and rounded apically and with numerous strong macrosetae in apical part of disc, space between base of disc and antecostal suture narrow, antecostal suture arcuate (Fig. 8d). FEMALE: spermatheca pear-shaped with small and shallow apical invagination, stem thin and irregularly coiled posteriorly (Fig. 8f); tergite and sternite VIII truncate apically (Figs 8g, h).
This species may be distinguishable from other Mocyta species by its large and dark brown to black pronotum, shape of spermatheca and apical structures of internal sac.
Distribution. This nearctic species is known from Newfoundland, New Brunswick, Quebec and Ontario.
Natural history. In New Brunswick, adults were found in sphagnum moss and litter in calcareous eastern white cedar fens and in a black spruce forest. One individual was collected from moldy conifer duff at the base of a large pine in a mixed forest. Adults were found in April and May in New Brunswick, and June to August elsewhere. This species seems to be associated with moist sphagnum moss.
types of Eurypronota discreta Casey and other Casey types. Anthony Davies (CNC) arranged several specimens for study from the CNC collection in Ottawa. Pamela Cheers (LFC) edited and corrected the first draft of the manuscript and Jim Hammond (NoFC) prepared the maps. Natural Resources Canada provided the funding for this study.