Epischnomyia tkoci Roháček 2018, sp. nov.

Epischnomyia tkoci sp. nov. (Figs 68–71,73–81) Type material. HOLOTYPE:, labelled: ‘ CHINA, Sichuan prov., Wenchuan, Aba, WOLONG, Wolong Nature Reserve, forested slope, 2050m, 31°01ʹ32ʺN, 103°10ʹ15ʺE, sweep. vegetation, indiv. coll., 24.vi. 2014, J. Hájek, J. Růžička & M. Tkoč lgt.’ and ‘ Holotypus, Epischnomyia tkoci sp.n., J. Roháček det. 2017’ (red label) (NMPC, genit. prep.). Description. Male. Total body length 2.90 mm; body bicolourous (Fig. 69), brown (mainly dorsally) and yellow to yellowish white (ventrally), most resembling the dark form of E. merzi but a bit darker. Head (Fig. 68) somewhat higher than long, also bicolourous but largely brown, with some parts yellow to whitish yellow. Occiput dorsomedially slightly concave, largely dark brown, with only subtriangular (tapered ventrally) medial area between vti, pvt and foramen dirty yellow and silvery white microtomentose but, in contrast to E. merzi, having a medial brown stripe continuing from ocellar triangle, tapering towards foramen and ending immediately above the latter; ventrolateral (dark brown) part of occiput sharply delimited from yellowish white postgena. Frons pattern similar to that of dark form of E. merzi – brown-darkened (darkest anteriorly), dull and distinctly striated between frontal triangle and orbits; frontal triangle very small, narrow (not wider than ocellar triangle), dark yellow and whitish microtomentose, reaching to middle of frons; ocellar triangle relatively small, dark brown and grey microtomentose; ocelli large. Orbit yellow to whitish yellow, whitish microtomentose, slightly tapered anteriorly and widened posteriorly where confluent with yellow medial area on occiput. Frontal lunule reduced, small, orange yellow. Face very narrow, medially less sclerotized, concave, brown and grey microtomentose, laterally with dark brown, relatively broad and bare marginal stripe (reaching onto ventral margin of gena). Parafacialia (very narrow) and gena (except dark marginal stripe) yellow, both with strikingly glittering silvery white microtomentum. Postgena whitish yellow, whitish microtomentose and contrasting with dark brown ventrolateral part of occiput. Mouthparts yellow (clypeus) to whitish yellow (ventrally); palpus dark brown at least in distal two-thirds. Cephalic chaetotaxy: all macrosetae long (Fig. 68); pvt also long and strongly crossed; vti longest of cephalic setae; vte shorter than vti and exclinately curved; oc subparallel, proclinate, only slightly shorter than vti and subequal to posterior ors; 3 ors, 2 posterior strong (hindmost ors as long as oc, middle about as long as vte), 1 anterior small, about one-third of middle ors; 1 additional microsetula in front of the foremost short ors; 3 pairs of medial microsetulae in the anterior half of frons; 1–2 inclinate setulae behind vte; postocular setulae short, numerous (10–11), in single row; postgena with several setulae and 1 longer posteroventral seta; 1 long vi (about as long as vte) but subvibrissa very reduced (or absent?), weak, shorter than anterior peristomal setula; 4 proclinate peristomal setulae. Palpus small, slender, with 2 (1 subapical, 1 ventral) dark setae and a few shorter ventral and lateral setulae. Eye suboval, with longest diameter slightly oblique and about 1.5 times as long as shortest. Gena low, its shortest height about 0.11 times as long as shortest eye diameter. Antenna slightly geniculate, with scape and pedicel yellow but 1st flagellomere largely brownish darkened (dirty yellowish only dorsally in front of base of arista and on posteroventral margin), elongately oval, laterally flattened and densely long white ciliate on anterior margin. Arista brown, with basal segments paler, only 1.8 times as long as antenna and relatively shortly ciliate. Thorax slightly narrower than head, yellow and brown (Fig. 69), and dull due to relatively dense greyish microtomentum. Mesonotum similarly coloured to that of dark form of E. merzi, largely brown but laterally with yellow longitudinal band reaching from posterior end of humeral callus to sides of postnotum and medially with very narrow and faint ochreous dorsocentral lines fading in front of suture and interrupted between both posterior dc macrosetae; scutellum largely brown with only small spots around bases of apical and laterobasal sc ochreous. Humeral callus largely brown but notopleural area yellow to yellowish white (ventrally). Pleural part of thorax whitish yellow, with brown dorsal band extended from cervix to base of abdomen and its width equalling dorsal half of mesopleuron. Postscutellum and postnotum brown except for yellowish ochreous lateral areas of the latter. Thoracic chaetotaxy (Fig. 69): 1 long hu; 2 long npl (anterior longer); 1 prs, 1 sa, 1 pa, all 3 very long, subequal in length; 3 postsutural dc, 1 anterior short (about twice as long as dc microseta in front of it), middle dc slightly shorter than prs, hindmost dc very long, as long as apical sc; only 2 rows + single seta of a 3rd row of ac microsetae on suture, 2 rows more posteriorly with hindmost pair of ac microsetae situated slightly behind the level of middle dc; 2 sc, laterobasal short and weak (much shorter than middle dc), apical sc very long; 1 ppl, weak but as long as half height of propleuron; 2 long stpl, anterior distinctly shorter, 1 setula in front of them and 5 below the latter; ventral part of sternopleuron with 3 pairs of longer setae. Scutellum elongately triangular, flat dorsally as in congeners. Legs yellow (coxae and trochanters yellowish white), only apical half of last tarsal segment brown. f 1 (Fig. 70) with ctenidial spine small, distinctly shorter than width of t 1 and with a number of long hair-like setae in posteroventral (longer setae) and posterodorsal row. f 2 with posteroventral row of erect setae, those in middle third thicker and shorter and those in distal fourth denser. t 2 with very weak ventroapical seta, hardly longer than maximum width of tibia; f 3 with dense posteroventral row of setae along entire length, 9–10 in proximal half longer and slender and 11–12 in distal half shortened, thickened and densely arranged (see Fig. 71), thus with more and much denser thickened setae than in both congeners (4–7 in E. merzi, 7–8 in E. triarmigera). Fore and hind basitarsus with somewhat prolonged golden yellow setulae ventrobasally and mid basitarsus with a row of ventral setulae proximal of which may be thicker. Wing (Fig. 69) long, slightly narrower than in E. merzi, with very similar brown and white longitudinal pattern but the dark band somewhat narrower (particularly when compared with that of E. merzi which has brown area distinctly expanded beyond dm cell, see ROHÁČEK 2009: Fig. 106). Veins dark brown, except for whitish yellow Sc, R 1, R 2+3 and most (from base to apex of R 2+3) of C. C with distinct spinulae between apices of R 1 and R 2+3. Shape of R 2+3 and R 4+5 as in other Epischnomyia species; M very slightly divergent from R 4+5 apically; r-m situated in basal two-fifths of dm cell; dm, CuA 1, A 1, alula and anal lobe also very similar to those of congeners. Wing measurements: length 3.22 mm, width 1.01 mm, Cs 3: Cs 4 = 1.49 (slightly lower than in relatives), rm\dm-cu: dm-cu = 3.33 (somewhat higher than in relatives). Haltere relatively small, with dirty yellowish stem and pale brown knob. Abdomen long, with dark brown T1–T5, S6–S8 and (darkest) epandrium; S1–S5 brown (as in E. triarmigera), all abdominal sclerites sparsely greyish microtomentose and more shining than thorax. Preabdominal terga large, broad, reaching far onto ventrolateral aspect of abdomen, of similar shape to those of congeners, with setae on more posterior terga denser and longer. Preabdominal sterna markedly narrower than terga, all somewhat trapezoidal, becoming distinctly wider posteriorly (S4 slightly wider than long, S5 distinctly wider than long and largest sternum). Postabdomen large and constructed similarly to that of other Epischnomyia species, with membranous, unpigmented and bare T6, large S7 (almost as long as S8), both S6 and S7 laterally bulging and anteriorly with dark marginal ledge but S6 not as large and without anterior internal lobe. S6 with 2 (1 longer) distinct setae, S7 with only 1 seta apart from a pair of setiform sensilla at anterior margin. S8 as long as epandrium and with sparse (7 or 8) setae at posterior margin. Genitalia. Epandrium (Figs 73, 74) slightly wider than high, longer than that of both relatives, with relatively dense and long setae, including 2 pairs of long and robust setae. Anal fissure narrowed in dorsal half (Fig. 73) so differing from that of congeners but cercus similar, small, pale-pigmented and finely setose. Medandrium distinctly lower and with sides sinuate, not rectangular as in that of other Epischnomyia species. Gonostylus (Figs 73, 74, 76) dissimilar to that of relatives, slender and elongate, only basally broader, with distal three-fourths narrow, slightly bent medially and posteriorly and with apex terminating in 2 blunt denticles (Fig. 76); its chaetotaxy also different, with denser internal setae and micropubescence reduced, restricted to subbasal area of outer side (see Fig. 76). Hypandrium (Fig. 77) robust but less asymmetrical and less bent than in relatives, also differing in having larger internal submembranous leaf-like lobes. Transandrium (Fig. 78) including inconspicuous short and flat caudal process also similarly formed but its dark dorsal ledge more sinuate; also basal membrane closely resembling those of congeners with its armature formed by small spine-like tubercles (Fig. 78). Pregonites (Fig. 77) less asymmetrical than those of congeners, each with anterior lobe bent internally and its posterior part bulging ventrally being narrower in caudal view (see Fig. 78, with setae omitted); anterior part of pregonite with 4 setae becoming longer ventrally and its posterior bulging part with 4 subequal setae, thus both with chaetotaxy dissim

Topic: Visual perception and processing mechanisms
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences