Scenopinus jerei, Pohjoismäki & Haarto, 2021

Pohjoismaeki, Jaakko & Haarto, Antti, 2021, Scenopinus jerei, a new species of window fly (Diptera, Scenopinidae) from Finland, ZooKeys 1059, pp. 135-156 : 135

Scenopinus jerei sp. nov.

Figures 1A, B , 2 , 3A, B , 4A, B , 4E, F

Type material.

Holotype (1♂): Finland, Sa: Kouvola, 674-679:347-350 [60.7686-61.2184, 26.4495-27.0000] / e.l. 2018 ex Strix aluco nest box. / M. Mutanen leg. // Scenopinus jerei sp. nov. Pohjoismäki & Haarto 2021 / ( Diptera : Scenopinidae ) / J. Pohjoismäki det. // HOLOTYPE [red label] [MZH] Paratypes: 1♂ (dissected, DNA barcoded JP2020-S1), 1♀, same collection data; // Scenopinus jerei sp. nov. Pohjoismäki & Haarto 2021 / ( Diptera : Scenopinidae ) / J. Pohjoismäki det. // PARATYPE [yellow label] [MZH]; 1♂: Finland, EP: Isokyrö / Orisberg 6983:[3]265 [62.8744, 22.3795]/ 7.7.1999/ A. Haarto leg.// SCENOPINIDAE / Scenopinus / Scenopinus vitripennis Meig./ det. A. Haarto 1999// PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [red label] [AHC]; 1♂: Finland, ES [ Etelä-Savo]: Rantasalmi/ Korhola 68720:[3]5802 [61.9458, 28.5278] / 27.6.2006/ A. Haarto leg.// SCENOPINIDAE / Scenopinus / sp./ det. A. Haarto 2006// PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [red label] [AHC]; 2♂: Finland, Kb: Ilomantsi/ Kelovaara 70008:36826 [63.0638, 30.6144]/ 24.7.2021/ J. Pohjoismäki leg. // PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [yellow label] [JPC]; 1♀: Finland, ES: Rantasalmi/ Korhola 68720:5802 [61.9458, 28.5278]/ 29.6.2006/ A. Haarto leg.// SCENOPINIDAE / Scenopinus / sp./ det. A. Haarto 2006// PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [red label] [AHC]; 1♀: Finland, Kb: Liperi/ Viinijärvi 6951:3615 [62.6451, 29.2425] / e larva 2013/ Ali Karhu leg.// linnunpönttö [nest box]// SCENOPINIDAE / Scenopinus / sp./ det. A. Haarto 2014/ AHa14-000891// PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [red label] [AHC]; 1♀: Finland, Kb: Liperi/ Käsämä suo 6950:3619 [62.6349, 29.3197]/ 26.-28.6.2013/ Ali Karhu leg.// SCENOPINIDAE / Scenopinus / sp./ det. A. Haarto 2020/ AHa20-000473// PARATYPE/ Diptera : Scenopinidae / Scenopinus jerei / Pohjoismäki & Haarto 2021 [red label] [MZT].

Diagnosis.

Scenopinus jerei sp. nov. belongs to the S. fenestralis group and is easily recognisable from the other species in this group based on the contrasting colour differences between the femora and the yellow to orange tibiae. The coxae as well as the knob of the halteres are always uniformly black or dark brown, similar to the colour of the thorax.

Description.

Male (Figs 1A ; 2A, B ; 4A, B, F, G ) (characters in square brackets refer to the holotype). Body length: [4.1]-4.9 mm (n = 6) [dried specimens, fresh specimens are longer).

Head (Fig. 2A, B ). Black with greasy-looking shine, including oral margin and occiput, apart from weak grey microtomentum around occipital foramen, mouth edge and antennal base; semi-circular, height 1.5-1.7 [1.6] (n = 6) × its maximum width in lateral view. Antennal insertion slightly below mid eye level. Antenna dark brown with pedicel and anterior part of flagellomere paler; scape short and subrectangular; pedicel short and cylindrical, [0.8]-1.0 (n = 6) × as long as wide, flagellomere laterally flattened, 1.8[1.9]-2.0 × as long as high, subrectangular, narrowing apically and 4.8-[5.4] (n = 6) × as long as pedicel and with subcircular, subapical, sensory pore on outer side. Eyes large and bare; fronto-orbital plates meeting at [0.25]-0.3 (n = 6) length of frons; no frontal vitta; gena reduced to narrow strip between lower eye margin and mouth edge. Diameter of ommatidia on upper half of compound eye, above antennal base, 2-3 × diameter of ommatidia on lower half. Ocellar triangle acute, distance between posterior ocelli distinctly shorter than their distance to anterior ocellus. Frons bare but patterned with minute pits. No setae or setulae on head, apart for short brown setulae at lower posterior part of gena behind mouth edge. Mouthparts, including palpus, black.

Thorax (Fig. 1A ). Dorsally and laterally black with greasy-looking shine. Scutum patterned with small rugae and minute, barely distinguishable setulae. Pleura with similar patterning but with more distinct, short, sparse, greyish to brownish setulae. Hirsuteness most developed on anepisternum, where longest setulae are approximately same length as width of flagellomere.

Legs (Fig. 1A ). Coxae black; femora brown and apically paler. Fore and mid tibiae [pale brown] to dirty orange, clearly paler than femora. Hind tibia otherwise of similar colour as femora but paler at base and apex. Hind coxa with thin black posterior setulae, longest setulae as long as width of coxa at its base. Femora with thin posterodorsal setulae, longest being 0.5 × as long as width of femora. Fore tibia preapically with [2]-3 ventral setulae. Mid tibia with two short, ventral, preapical setae and two adjacent setulae. Hind tibia with one ventral preapical setula and thin posteroventral setulae covering proximal half, longest of which are as long as width of tibia. Apart from aforementioned setae and setulae, all legs covered in minute setulae that provide rugous texture.

Wings (Fig. 1A ). Hyaline with greyish tinge. Tegula black, basicosta brownish black, wing veins brown. Petiole and knob of haltere uniformly black.

Abdomen (Fig. 1A ). Elongated, dorsally flattened except for domed terminal segments, black in colour, with greasy shine and covered by irregular, minute, robust setulae. Tergites 6, 7, and 8 with black marginal setulae, longest of which ca. as long as width of hind femora.

Terminalia (Fig. 4A, B, E, F ). Hypandrium divided to two similar subrectangular halves, posterior margin with long dense setulae (Fig. 4A ). Epandrium similarly divided into subtriangular halves with long posteroventral marginal setulae (Fig. 4B ). Cercus subtriangular (Fig. 4E ); gonocoxal apodeme scapula-shaped and curving slightly inwards at its posterior part; gonostylym bluntly subrectangular, posteriorly concave and ending with a ventral apex. Distiphallus with long, narrow, curved apical processes, hooking outwards prior to apex (Fig. 4F ). Aedeagus rod-shaped, slightly bent at middle and with a short-forked apex.

Female (Figs 1B , 3A, B ). Differs from male as follows:

Body length: 4.3-5.7 mm (n = 4). Head (Fig. 3A, B ). Frons broad, at its narrowest point 0.62-0.69 (n = 4) × as wide as an eye in dorsal view. Frons shiny black with minute longitudinal rugae on frontal stripe and transverse rugae on sides. Orbital plates smooth and shiny. Ocellar triangle equilateral. No obvious size difference between ommatidia of upper and lower half of compound eye. Thorax (Fig. 1B ). Very weak whitish grey microtomentum at anterior parts of postpronotum and proepisternum. Abdomen (Fig. 1B ). Dorsally flattened along its entire length. Terminalia. Last visible tergite 9 bluntly triangular at its posterior edge and not divided into hemitergites.

DNA barcode divergence among Scenopinus .

Scenopinus spp. are poorly covered in the DNA barcode databases, such as Barcode of Life Database (BOLD, www.boldsystems.org) or GenBank. It is noteworthy that all S. fenestralis specimens in the databases from Europe to North America have almost identical COI sequences and represent the same barcode index number (BIN). The DNA barcode of Scenopinus jerei sp. nov. differs markedly from the other northern European species, its closest match being Scenopinus fenestralis from which it is separated by 12.48% sequence difference (Fig. 5 ). There are no other closer matches among the barcode sequences in the BOLD or GenBank.

Notes

on the biology and distribution of Scenopinus jerei sp. nov. The larvae of Scenopinus species are predators of other invertebrates living in dry organic substrates, such as in animal nests. In Finland, Scenopinus jerei sp. nov. has been collected inside sheds, attics and indoor storages as well as reared from nest boxes of birds. These rearings produced large numbers of tineid moths ( Lepidoptera : Tineidea), especially Monopis laevigella (Denis & Schiffermüller), but also other Monopis spp., Niditinea striolella (Matsumura), and Tinea spp. Other insects observed from the same nest boxes included Ceratophyllus fleas, various beetles ( Histeridae , Dermestidae ) and flies ( Piophilidae , Fanniidae , Heleomyzidae ). Apart for two male specimens found dead on a windowsill in an attic of an old house in Kelovaara on July 24 (see type specimens), most observations are from third week of June. According to the observations of Jere Kahanpää (pers. comm.), Scenopinus jerei sp. nov. hibernates as full-grown larvae and the adults emerge in a couple of weeks in room temperature rearing conditions. Based on the collection locations, it is likely that Scenopinus jerei sp. nov. is a boreal forest specialist.

Like other Scenopinus spp., Scenopinus jerei sp. nov. is not very active flier, does not visit flowers and therefore is rarely collected by active netting or traps. Judging from the few Finnish observations, the species appears widespread in the southern and central parts of the country. We are certain that Scenopinus jerei sp. nov. can also be found in boreal forest biotopes in the other Nordic countries and Russia but has been until now overlooked.

Etymology.

This species is named after Mr. Jere Kahanpää, Helsinki, who was to first to discover that the taxon is new to science and kindly agreed with the current arrangement for its formal description.

Provisional key to the identification of European Scenopinidae species

Because the existing literature on the European species of Scenopinidae are outdated or difficult to obtain, we felt necessary to provide a key for the known European species of Scenopinidae . We must emphasise that we have been only able to examine the species with specimens listed in this paper, for which the identification key should work well. For the remainder, our approach was to go through the written species descriptions and pick features which we judged, by our collective species identification experience, to be useful for determination. To us this approach was better justified than reproducing the keys given in earlier literature, which are often difficult to follow or focus on limited number of poorly defined features. The diagnostic features for the key have been obtained from the descriptions in Kröber (1925), Trojan (1956), Kelsey (1969), Krivosheina (1981), Narchuk (1988), and Carles-Tolrá (2001). Fortunately, the European species separate into three easily recognisable species groups, each with relatively few species. The species groups appear in the key in alphabetical order, enabling fast navigation when one is familiar with the groups. Although result appears satisfactory, the key might not capture all the variations seen within each species and we strongly encourage DNA barcoding of specimens for future reference. In any case, we hope that this key can form a basis for forthcoming work with this interesting family of flies.

Figures

Figure 1. Habitus of northern European Scenopinus fenestralis group species of Scenopinidae A holotype male of Scenopinus jerei sp. nov., Kouvola, Finland B paratype female of Scenopinus jerei sp. nov., Kouvola, Finland C male of Scenopinus fenestralis, Liperi, Finland D female of Scenopinus fenestralis, Liperi, Finland E male of Scenopinus vitripennis, Wuerttburg, Germany. Photograph by Susanne Leidenroth F female of Scenopinus vitripennis, Warszawa, Poland. Photograph by D. Schimrosczyk G female of Scenopinus glabrifrons, Ockstadt, Germany. Scale bar: 500 mm.

Figure 2. Male heads of Scenopinus species A lateral view of holotype Scenopinus jerei sp. nov., male head B frontal view of holotype Scenopinus jerei sp. nov., head C lateral view of Scenopinus fenestralis male head D frontal view of Scenopinus fenestralis male head. For the illustrations of male heads of S. vitripennis and S. glabrifrons, see Krivosheina (1981). Scale bar: 500 mm.

Figure 3. Female heads of Scenopinus species A lateral view of paratype Scenopinus jerei sp. nov., female head B frontal view of paratype Scenopinus jerei sp. nov., head C lateral view of Scenopinus fenestralis female head D frontal view of Scenopinus fenestralis female head E l ateral view of Scenopinus vitripennis female head. Photograph D. Schimrosczyk F frontal view of Scenopinus vitripennis female head. Photograph D. Schimrosczyk G lateral view of Scenopinus glabrifrons female head H frontal view of Scenopinus glabrifrons female head. Scale bar: 500 mm.

Figure 4. Scenopinus male terminalia A hypandrium of Scenopinus jerei sp. nov. paratype B epandrium of Scenopinus jerei sp. nov. paratype C hypandrium of Scenopinus fenestralis D epandrium of Scenopinus fenestralis E terminal segments of Scenopinus jerei sp. nov. paratype F aedeagus of Scenopinus jerei sp. nov. paratype G terminal segments of Scenopinus fenestralis H aedeagus of Scenopinus fenestralis. aed - aedeagus; aed lb - aedeagal lobe; distph - distiphallus; ej apod - ejaculatory apodeme; epand - epandrium; goncx apod - gonocoxal apodeme; gonst - gonostylym; hypand - hypandrium; pm sh - parameral sheath. For the illustrations of male terminalia of S. vitripennis and S. glabrifrons, see Krivosheina (1981).

Figure 5. Maximum likelihood tree of COI sequence similarities among Scenopinus spp. Numbers at nodes indicate posterior probabilities and scale bar the relative sequence divergence. BOLD sample ID number is given after the species name.