The Genus Spinopygina gen. nov. (Diptera, Sciaridae) from Western North America: Preliminary Molecular Phylogeny and Description of Seven New Species

Simple Summary Black-winged fungus gnats (family Sciaridae) are one of the most species-rich groups of flies (Diptera), with about 3000 described species worldwide. Their taxonomy is notoriously challenging, as many genera are difficult to delimit and species identification relies almost exclusively on the male genitalia. Existing phylogenetic hypotheses based on DNA sequences are often contradictory, presumably due to low taxon or gene sampling. In this paper, a new multigene phylogenetic analysis is presented to support the concept and monophyly of a new genus, containing eight species, seven of them being described as new to science. Abstract The genus Spinopygina gen. nov. (type species Camptochaeta uniceps Hippa & Vilkamaa, 1994) from western North America is described. The genus includes the following eight species: Spinopygina acerfalx sp. nov.; S. aurifera sp. nov.; S. camura sp. nov.; S. edura sp. nov.; S. peltata sp. nov.; S. plena sp. nov.; S. quadracantha sp. nov.; and S. uniceps (Hippa & Vilkamaa, 1994) comb. nov., transferred from Corynoptera Winnertz. The new species are described and Spinopygina uniceps is re-diagnosed. The species are keyed and illustrated. In the maximum-likelihood phylogenetic hypothesis based on four gene fragments (28S, 18S, 16S and COI), Spinopygina gen. nov. appears as the sister group of Claustropyga Hippa, Vilkamaa & Mohrig, 2003. In the same analysis, a remarkable, undescribed species is placed within Camptochaeta Hippa & Vilkamaa clade.


Introduction
Sciaridae (black-winged fungus gnats) is one of the little studied terrestrial Dipteran families with about 3000 described species in about 100 genera and subgenera, occurring in all continents [1]. Most species live in shady forested and moist habitats. Larvae are predominantly saprophagous and live in soil and litter or under bark of dead wood. The taxonomy is notoriously challenging, as many genera are difficult to delimit and are rich in small and rather similar species. The species identification relies almost exclusively on the male hypopygium, and in most genera the females are unidentifiable. Some trials to reconstruct phylogenies extensively over the family or focused on a limited number of taxa have been made, either using morphological characters [1][2][3][4][5][6][7][8] or using molecular markers [9][10][11][12]. Often the hypotheses obtained have been contradictory, presumably due to variable choice of morphological characters, insufficient number of molecular characters used or because of low taxon sampling. The paper by Shin et al. [9] is the most comprehensive of the molecular analyses, but it misses many crucial genera from the Holarctic region and lacks almost completely the extra-Holarctic taxa in its taxon sampling. Shin et al. [9] divided the family into three subfamilies, and later [10] named a fourth, but

Morphological Methods
The material originated from Malaise trap samples, and all specimens were detected and picked out from unsorted sciarid or insect material stored in ethanol. The holotype of Camptochaeta uniceps was obtained from Canadian National Collection, Ottawa, Canada (CNC) and a paratype from Royal British Columbia Museum, Victoria, Canada (RBCM), the other paratypes having been deposited in Zoological Museum, Finnish Museum of Natural History. The specimens were mounted on microscope slides in Euparal, after dehydrating them in absolute ethanol. Only males were studied: the females are unknown. The terminology and methods of measuring structures follow Hippa and Vilkamaa [28] and Hippa et al. [3,37]. The photographs of the slide-mounted specimens were taken with a Leica MC170 HD camera mounted on Leica DM 4000 B LED research microscope. The habitus of Spinopygina uniceps was photographed with Canon EOS 5DS digital SLR camera with a Canon MP-E 65 mm macro lens. The Figures were processed with Photoshop version CS5, CorelDraw2017 and CorelPhotopaint2017. The type material of the new species is deposited in Zoological Museum, Finnish Museum of Natural History, Helsinki, Finland (MZH). The specimen data of the MZH specimens will be added into the specimen database of the Finnish Museum of Natural History (Luomus) and will be found with the specimen codes https://luomus/GE.####.
This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The LSID for this publication is: urn:lsid:zoobank.org:pub:9962DD66-13CC-4191-B6FF-0A7DD1934F75.

Molecular Methods
For the ingroup, representatives of taxa from the three subfamilies of Sciaridae were chosen as well as selected terminals from the non-monophyletic 'Pseudolycoriella group' of genera proposed by Shin et al. [9,10]. From the latter group, terminals were chosen to adequately cover the morphological diversity of the group.
The specimens used for DNA analysis (Table 1) were alcohol-preserved (70% to 99.9% ethanol). The DNA was extracted using NucleoSpin Tissue Kit (Macherey-Nagel, Düren, Germany) following manufacturers' protocols. PCRs were performed using primers listed by Shin et al. [9]. All amplified products were purified using Gel/PCR DNA Fragments Extraction Kit (Geneaid, New Taipei City, Taiwan) and subsequently, the samples were sequenced by Eurofins (Hamburg, Germany). All sequences were assembled, manually inspected, and primers trimmed in SeqTrace [38]. New sequences were deposited in the GenBank database, with their accession numbers listed in Table 1.
Diagnosis. Small to medium sized Sciaridae, wing length 1.6-2.2 mm. Antenna long, flagellomeres with long setae and necks. Mouth parts small, maxillary palpus with 2 segments, 2nd segment much reduced. Anal lobe of wing small, halter with long stalk. Body setosity dark, long and strong. Legs long and slender, fore tibial organ poorly differentiated. Intergonocoxal area long or moderate, without medial lobe. Gonocoxae united medially, setae at medial margins short. Gonostylus impressed or deeply excavated medially, with lambda-shaped basomedial sclerotization; with strong megasetae with basal bodies, including (in most species) strongly procurved basal megaseta; without apical tooth. Tegmen modified, with flat apicolateral parts, without detectable aedeagal teeth.
Thorax ( Figure 2). Brown; setae dark. Acrostichal setae few anteriorly, dorsocentral and lateral setae in indistinct rows of a few long and strong and short and fine setae. Scutellum with 2 long and strong setae and a few short and fine setae. Posterior pronotum non-setose. Anterior pronotum and prothoracic episternum with a few setae, other pleural sclerites non-setose. Mesothoracic katepisternum high with oblique anterior margin.
Wing ( Figure 3A-C). Fumose. Length 1.6-2.2 mm. Anal lobe small. Veins distinct, except stM. Membrane non-setose, veins C, R and R1 setose, R5 with only dorsal setae, bM, r-m, stM, M and stCuA non-setose. c/w 0.70-0.90, R1/R 0.70-1.15, R1 joining C well before level of base of M-fork. Halter yellow, with long stalk. Thorax ( Figure 2). Brown; setae dark. Acrostichal setae few anteriorly, dorsocentral and lateral setae in indistinct rows of a few long and strong and short and fine setae. Scutellum with 2 long and strong setae and a few short and fine setae. Posterior pronotum non-setose. Anterior pronotum and prothoracic episternum with a few setae, other pleural sclerites non-setose. Mesothoracic katepisternum high with oblique anterior margin.   Legs ( Figure 3D,E). Yellow or pale brown, long, femora slender; setae dark; tibial spurs 1:2:2, fore tibial spur as long as tibial width or slightly longer, middle and hind left and right tibial spurs subequal in size, longer than tibial width. Fore tibia without spinose setae, middle tibia rarely with 1 spinose seta, hind tibia with dorsal row of strong spinose setae. The retrolateral apical setae of hind tibia fine. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Tarsi unmodified, long, length of fore basitarsomere/length of fore tibia 0.47-0.63. Tarsal claws unmodified, without teeth.
Abdomen (Figures 4-9). Pale brown or yellowish, normal, slender; setae dark, long and strong. Hypopygium brown or yellowish, as abdomen. Intergonocoxal area long or moderate, without lobe(s). Gonocoxa unmodified, longer than gonostylus, gonocoxae fused ventromedially; rather richly setose, setae at ventromedial margin short, medial membrane non-setose; with 1 elongated seta ventrally and dorsally at apicomedial corner. Gonostylus elongated, widest medially and distinctly narrowed towards apex or evenly wide and slightly narrowed towards apex, strongly excavated or at least slightly Legs ( Figure 3D,E). Yellow or pale brown, long, femora slender; setae dark; tibial spurs 1:2:2, fore tibial spur as long as tibial width or slightly longer, middle and hind left and right tibial spurs subequal in size, longer than tibial width. Fore tibia without spinose setae, middle tibia rarely with 1 spinose seta, hind tibia with dorsal row of strong spinose setae. The retrolateral apical setae of hind tibia fine. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Tarsi unmodified, long, length of fore basitarsomere/length of fore tibia 0.47-0.63. Tarsal claws unmodified, without teeth.
Female unknown. impressed medially, with lambda-shaped basomedial sclerotization; without apical tooth; with apical, subapical and medial megasetae, or only apical or subapical megasetae present; megasetae strong and with distinct basal bodies, in some species basalmost megaseta distinctly procurved; with some elongated setae medially and apically. Tegmen variable in shape, truncate or slightly curved apically, slightly curved basolaterally, constricted subapically, membranous or with sclerotized rim apically, with flat apicolateral parts; parameres sclerotized, approaching each other and joining to sclerotized rim or ending at apex separately. Apodemes of tegmen and aedeagal apodeme usually short, aedeagal teeth not detectable. Tergite 9 rather narrow, with long and strong setae. Tergite 10 (cercus) normal.

Comparative Diagnosis of Spinopygina gen. nov.
Mohrig et al. [13] transferred Camptochaeta uniceps Hippa &Vilkamaa, 1994 into the Corynoptera spinifera group sensu [1]. Spinopygina gen. nov. resembles the C. spinifera group in having a rather similar lambda-shaped basomedial sclerotized structure of the impressed or excavated gonostylus, in lacking the apical tooth of gonostylus, in having the megasetae

Comparative Diagnosis of Spinopygina gen. nov.
Mohrig et al. [13] transferred Camptochaeta uniceps Hippa &Vilkamaa, 1994 into the Corynoptera spinifera group sensu [1]. Spinopygina gen. nov. resembles the C. spinifera group in having a rather similar lambda-shaped basomedial sclerotized structure of the impressed or excavated gonostylus, in lacking the apical tooth of gonostylus, in having the megasetae with strong basal bodies, in having an apical gonostylar megaseta in all and a strongly curved basal gonostylar megaseta in part of the species. Spinopygina differs from the C. spinifera group as well as from the Corynoptera parvula group sensu [1] in important characters: the long necks of antennal flagellomeres, the 2-segmented maxillary palpus without the sensory pit, the long stalk of the halter, the indistinct, not impressed fore tibial organ, the basoven-trally united gonocoxae with distinctly shortened setae at their ventromedial margins and the tegmen with flat apicolateral parts and the apparent lack of the aedeagal teeth; see, e.g., Figures 4,5 and 30A,B in Hippa & Vilkamaa (1994) [36]. Moreover, Spinopygina differs from Camptochaeta Hippa &Vilkamaa, 1994 in the sense of [1] in the lack of the apical tooth of the gonostylus in addition to the characters mentioned above.
Spinopygina resembles Claustropyga Hippa, Vilkamaa & Mohrig, 2003 in having the maxillary palpus 2-segmented (in part of Claustropyga), the sensilla scattered on the dorsal side of 1st segment of the maxillary palpus, in having a weakly modified fore tibial organ, in having the medial part of the gonostylus impressed or excavated, in having distinct basal bodies of the gonostylar megasetae and in having the megasetae strong at least in part of the species, in having the gonocoxae united basoventrally with the intergonocoxal area long or at least moderate. Spinopygina differs in having the basomedial part of gonostylus impressed with the lambda-shaped sclerotized structure (the impression lacks in Claustropyga), in having long flagellomeral necks and stalk of halter and in the lack of the apical tooth of gonostylus (lacks also in one known species of Claustropyga). Moreover, even if long, the intergonocoxal area of Spinopygina is not lobe-like produced as in most species of Claustropyga.
Spinopygina resembles Xylosciara Tuomikoski, 1960 in having a long intergonocoxal area, in having strong gonostylar megasetae including apical ones and in having a poorly differentiated patch of setae on the fore tibial organ. Spinopygina differs most strikingly in having 2-segmented maxillary palpus, longer necks and setae of antennal flagellomeres, in having strong and dark body vestiture and in having a modified tegmen and a strongly hollowed gonostylus.
Some species of Spinopygina resemble Keilbachia Mohrig, 1987 in having a strong procurved megaseta basally or subbasally on the gonostylus. Some species of Keilbachia lack the apical tooth of gonostylus and some species have a strongly modified tegmen reminiscent of that of Spinopygina, but Keilbachia has a 3-segmented maxillary palpus with a sensory pit on the 1st palpal segment, the fore tibial organ in depression at least in part of the species and it has ventromedially separated gonocoxae.
By the reduced maxillary palpus with sensilla scattered, long antennal flagellomeral bodies and their necks, long and slender legs, the long and oblique mesothoracic katepisternum, the strongly reduced anal lobe of wing and the poorly modified fore tibial organ, Spinopygina resembles Epidapus Haliday, 1851 and in lacking the apical tooth of gonostylus, especially Epidapus (Pseudoaptagogyna) absconditus group sensu [1]. Epidapus absconditus (Vimmer, 1926) has, like Spinopygina, strong apical-subapical gonostylar megasetae with distinct basal bodies. However, the megasetae of Epidapus absconditus are stout, straight and symmetrically narrowed at apex, not long and curved as in Spinopygina. The four megasetae of the related Epidapus quadrispinosus Mohrig & Mamaev, 1990 are all recurved. Moreover, Spinopygina differs from the E. absconditus group in having subequal left and right spurs on middle and hindtibia (unequal), in having the intergonocoxal area long with the gonocoxae united basoventrally (short and separate), with shortened setae at the ventromedial margin (equal), in having the tegmen strongly modified and with distinctly sclerotized parameres (simple, laterally and apically roundish and completely membranous tegmen in Pseudaptagogyna Vimmer, 1926) and in having the gonostylus impressed or excavated (in Pseudoaptagogyna convex medially) and in having (in part of the species) a curved basal megaseta in the gonostylus.
Spinopygina differs from all above-mentioned genera in having the tegmen with flat apicolateral parts and in lacking the aedeagal teeth (the teeth not detectable using a compound microscope.

Descriptions of New Species
Spinopygina acerfalx sp. nov. Figures 2B, 3A, 4A and 9A. LSID urn:lsid:zoobank.org:act: 008D0F6D-919A-4915-99A8-8AB979A3DAD2. Comparative diagnosis. By its tegmen, Spinopygina acerfalx sp. nov. is very similar to Spinopygina camura sp. nov., S. quadracantha sp. nov. and S. uniceps (Hippa & Vilkamaa). All have the tegmen narrowed subapically, with flat apicolateral parts and with the parameres joining a shortly sclerotized rim apically. Spinopygina acerfalx is similar to S. edura sp. nov. and differs from all above-mentioned species in having only three, not four or five, gonostylar megasetae. Moreover, in the form of the gonostylus and in the arrangement of the gonostylar megasetae Spinopygina acerfalx resembles S. edura, but the latter is distinct in having the tegmen much smaller and more sclerotized basally and in having the parameres wide apart, joining the broadly sclerotized rim separately at the apex.
Etymology. The name is a Latin noun in apposition, formed from acer, sharp, and falx, sickle, referring to the sharp and curved gonostylar megasetae. Description. Male. Head. Face and antenna uniformly brown, maxillary palpus pale brown. Eye bridge 1-2 facets wide. Body of 4th antennal flagellomere 2.60-3.20× as long as subapically wide, the neck longer than wide, the longest setae longer than the width of flagellomere. Face with 5-9 dark long and short setae. Clypeus non-setose or with 1 dark seta. Maxillary palpus with 2 segments; 2nd segment reduced; 1st segment with 1 sharp seta, with large indistinct dorsal patch of sensilla, 2nd segment with 1-5 setae.
Legs. Yellow, long. Fore femur slender. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Fore tibial spur longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.63.
Spinopygina aurifera sp. nov. Figures 1D, 3B, 4B and 9B. LSID urn:lsid:zoobank.org:act: B9089867-2FA5-4A03-92E4-5C99E60BD592. Comparative diagnosis. In having the basal megaseta of the gonostylus strongly procurved, Spinopygina aurifera sp. nov. resembles S. camura sp. nov. and S. uniceps (Hippa and Vilkamaa) but by its form of the gonostylus and the tegmen, S. aurifera is not very similar to any other known species of the genus: the apicalmost megaseta is shifted to a subapical position and the two medial megasetae are in a lobe-like extension of the ventromedial margin of the gonostylus. The tegmen is characteristic in being strongly constricted at the middle, and in having the apex wide and roundish and in having the flat apicolateral parts small and triangular. Spinopygina aurifera differs from all other species of the genus in having a peculiar conical lobe apicodorsally in the gonocoxa.
Etymology. The name is a Latin noun in apposition, from the words auris, ear, and the suffix -fer, bearing, referring to the ear-like apicolateral parts of the tegmen. Description. Male. Head. Face and antenna uniformly brown, maxillary palpus pale brown. Eye bridge 1-2 facets wide. Body of 4th antennal flagellomere 2.25-2.55× as long as subapically wide, the neck longer than wide, the longest setae longer than the width of flagellomere. Face with 5-7 dark long and short setae. Clypeus non-setose or with 1 dark seta. Maxillary palpus ( Figure 1D) with 2 segments; 2nd segment reduced; 1st segment with 1(2) sharp setae, with an indistinct dorsal patch of sensilla, 2nd segment with 3-5 setae.
Legs. Yellow, long. Fore femur slender. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Fore tibial spur as long as tibial width. Length of fore basitarsomere/length of fore tibia 0.47. Abdomen. Pale brown; setae dark, long and strong. Hypopygium ( Figure 4B) brown, as abdomen. Intergonocoxal area long, with short setosity. Gonocoxa wide, slightly longer than gonostylus; setosity normal, at medial margin shorter. Gonostylus elongated, slightly curved, strongly excavated medially; with a few elongated setae apically and medially; without apical tooth, with 4 megasetae, 1 subapical and 2 medial at ventral margin and 1 basally arising from medial excavation, the megasetae long and strong, nearly straight except the basalmost one procurved, all with basal bodies. Tegmen ( Figure 9B) longer than wide, curved apically, constricted laterally, with parameres ending wide apart at apex; with small triangular apicolateral parts. Aedeagal apodeme rather short, aedeagal teeth not detectable.
Spinopygina camura sp. nov. Figures 1C, 5A and 9C. LSID urn:lsid:zoobank.org:act: 144A1DDD-712D-4B81-862A-735709641561. Comparative diagnosis. Spinopygina camura sp. nov. is distinguished from all other species of the genus in having five instead of three or four gonostylar megasetae, the basalmost of which is strongly procurved (a paratype of S. quadracantha has five megasetae on one of its gonostyli) Spinopygina uniceps (Hippa and Vilkamaa) and S. aurifera sp. nov. also have a procurved basal megaseta on their gonostylus but they have only four megasetae. See also under S. acerfalx sp. nov. and S. quadracantha sp. nov.
Etymology. The name is a Latin adjective, camura, curved, referring to the curved basal megaseta of the gonostylus. Wing. Fumose. Length 2.0 mm. Width/length 0.40-0.45. Anal lobe small. R1/R 0.80. c/w 0.80. stM slightly longer than M-fork, bM shorter than or as long as r-m, stCuA shorter than bM. bM and r-m non-setose. Halter yellow, long.
Legs. Yellow, long. Fore femur slender. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Fore tibial spur longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.60.
Comparative diagnosis. By its gonostylus with a sharp apex and three megasetae Spinopygina edura sp. nov. is very similar to S. acerfalx sp. nov. although the former has the medial megaseta slightly closer to apex of the gonostylus. Spinopygina edura differs from all the species of the genus in its small and more sclerotized tegmen with concave parameres joining a broadly sclerotized rim apically. Description. Male. Head. Face and antenna uniformly brown, maxillary palpus pale brown. Eye bridge 1-2 facets wide. Antennae in poor condition in the specimen studied, the neck longer than wide. Face with 10 dark long and short setae. Clypeus with 1 dark seta. Maxillary palpus with 2 segments; 2nd segment reduced; 1st segment with 1 sharp seta, with an indistinct dorsal patch of sensilla, 2nd segment with 3-4 setae.
Legs. Yellow, long. Fore femur slender. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Fore tibial spur slightly longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.60.
Etymology. The name is formed from the Latin word pelta, shield, referring to the wide tegmen.
Material  Figure 1B) as long as subapically wide, the neck longer than wide, the longest setae longer than the width of flagellomere. Face with 5-9 dark long and short setae. Clypeus with 1 dark seta.
Legs ( Figure 3D). Yellow, long. Fore femur slender. Fore tibial organ not impressed or proximally bordered, with small patch of a few setae. Fore tibial spur longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.58.
Abdomen. Pale brown; setae dark, long and strong. Hypopygium ( Figure 6A) brown, as abdomen. Intergonocoxal area long, with short setosity. Gonocoxa rather narrow, much longer than gonostylus; setae rather short, at medial margin shorter. Gonostylus elongated, rather straight, the medial side impressed; with a few elongated setae apically; without apical tooth, with 4 megasetae, 1 at apex in dorsal position, 1 subapically in ventral position and 2 slightly more mediad in dorsal and ventral positions, the megasetae long and strong, nearly straight, with short basal bodies. Tegmen ( Figure 9E) shorter than wide, hyaline and slightly produced apically, roundish basolaterally and slightly constricted subapically, with parameres ending separately wide apart at apex; with flat apicolateral parts. Aedeagal apodeme long, aedeagal teeth not detectable.
Legs. Yellow, long. Fore femur slender. Fore tibial organ ( Figure 3E) not impressed or proximally bordered, with indistinct patch of a few setae. Fore tibial spur longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.50.
Spinopygina quadracantha sp. nov. Figures 7 and 9G. LSID urn:lsid:zoobank.org:act: E8ADE6BD-FF9F-4F09-931A-3DAD514FDCEA. Comparative diagnosis. In having all gonostylar megasetae long and slightly recurved, Spinopygina quadracantha sp. nov. resembles S. acerfalx sp. nov. and S. edura sp. nov. but differs in having four instead of three megasetae. However, two of the studied specimens have an additional procurved megaseta at the basal part in one of their gonostyli ( Figure 7B). These gonostyli with 5 megasetae are difficult to distinguish from those of Spinopygina camura sp. nov. but the tegmen of S. quadracantha is bigger with larger apicolateral flat parts. A large tegmen with convex parameres joining into a short sclerotized rim apically is fairly similar to that of S. acerfalx and differs distinctly from that of S. edura sp. nov. See also under the latter.
Etymology. The name is a Latin noun in apposition, from the words quadrus, four, and acantha, spine, referring to the four gonostylar megasetae.
Material Description. Male. Head. Face and antenna uniformly brown, maxillary palpus pale brown. Eye bridge 2 facets wide. Body of 4th antennal flagellomere 2.40-3× as long as subapically wide, the neck longer than wide, the longest setae longer than the width of flagellomere. Face with 4-10 dark long and short setae. Clypeus with 1 dark seta. Maxillary palpus with 2 segments; 2nd segment reduced; 1st segment with 1-2 sharp setae, with an indistinct dorsal patch of sensilla, 2nd segment with 1-3 setae.
Legs. Yellow, long. Fore femur slender. Fore tibial organ with weak vestiture, forming an indistinct patch of few setae. Fore tibial spur longer than tibial width. Length of fore basitarsomere/length of fore tibia 0.60.
Comparative diagnosis. By its form of gonostylus with four megasetae and by the tegmen with flat apicolateral parts and the parameres joining a short apical rim, Spinopygina uniceps (Hippa & Vilkamaa, 1994) most resembles S. quadracantha sp. nov. but differs in having a shorter apical megaseta of the gonostylus, in having the basal megaseta distinctly procurved and with a long basal body and placed in the medial excavation instead at the ventromedial margin of the gonostylus. Spinopygina uniceps has the apex of tegmen narrower and with smaller flat apicolateral parts (Figures 7 and 8

Phylogeny
In general, the present hypothesis ( Figure 10), based on the same gene markers, is similar to the earlier published phylogenies [9,10,12]. The proposed subfamilies Sciarinae, Chaetosciarinae, Cratyninae and Megalosphyinae appear with good supports, as well as the polyphyletic Pseudolycoriella group of genera.
In this study, Spinopygina nested with Claustropyga as its sister group. As in the analysis of [12], Claustropyga in its original sense [3] was not monophyletic, C. refrigerata (Lengersdorf, 1930), in the earlier morphological cladistic analysis [3] appearing as the sister group of all other species of Claustropyga, now appeared in the Megalosphyinae clade. Moreover, Pseudolycoriella porotaka nested in the Cratyninae clade, although with low support. The placement of this genus was different also in the previous molecular analyses [9,12]. Morphologically, Pseudolycoriella is not very similar to any other genus of Sciaridae.
The former placement [13] of S. uniceps into the Corynoptera spinifera group proposed by Menzel and Mohrig (2000) [1] is not supported, and that group appears as polyphyletic. Interestingly, the two analyzed species of the group, C. spinifera Tuomikoski, 1960 and C. verrucifera (Lengersdorf, 1952), included in Camptochaeta [36] and subsequently transferred into the C. spinifera group [1], in the present hypothesis appear in the Camptochaeta clade with strong support. Moreover, the present hypothesis supports the close relationship between Keilbachia and Camptochaeta. The consequent changes in the classification as well as the description of the new species of Camptochaeta with an exceptional tegmen will be done in another publication (Vilkamaa et al. in prep.) Morphological similarities and differences in Spinopygina to Claustropyga, Corynoptera spinifera group and other relevant taxa are discussed under Comparative diagnosis of Spinopygina.

Discussion
Spinopygina gen. nov. has the structure of its tegmen as a unique character. By the combination of this and other characters, although the latter shared with many other genera, the genus is easy to identify.
Spinopygina shares quite a few morphological characters with many other genera, and a hypothesis of its phylogenetic position and of the sister group relationship between Spinopygina and Claustropyga were only possible by analyzing molecular characters. Although the molecular data were available from only two of the eight species, these species represent two different morphological types of Spinopygina, and the monophyly of the eight known species is well founded.
Judging from the few collection localities of the material for the present study, it is highly probable that more species of the new genus will be found in the western Nearctic region.
Regarding the whole sciarid fauna, the Nearctic region is far less known than the Palaearctic fauna [1,13] and it is possible that more new genera remain to be discovered in the region, especially in the less studied western parts.

Data Availability Statement:
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to ongoing research.