Epischnomyia tkoci, Roháček, 2018

Roháček, Jindřich, 2018, First Anthomyzidae (Diptera) from China: a new genus, six new species and new records, Acta Entomologica Musei Nationalis Pragae 58 (1), pp. 35-76 : 57-60

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 dissimilar to that of relatives. Postgonite ( Fig. 77 ) very similar to that of E. merzi including long seta in proximal third and minute setiform sensilla externally. Aedeagal part of folding apparatus ( Fig. 81 ) with asymmetrical armature different from that of both relatives, on left side composed of dark robust elongate spines (2 anterodorsal, and a group of 3 fused posteroventral) and fine striae ( Fig. 81 ), and on (larger) right side with an area of dense flat short spines and 1 elongate sclerotized posteroventral band terminating in 2 fused dark spines ( Fig. 75 ); connecting sclerite closely resembling those of other Epischnomyia species, short, heavily sclerotized and dark-spinose. Phallapodeme and aedeagus of the same general construction as in Epischnomyia species but basal fork of phallapodeme less deep and less asymmetrical; also phallophore similarly projecting into robust epiphallus but its distal part longer ( Fig. 81 ). Saccus with armature distinctly different ( Fig. 81 ), having 4 (only 1 robust, others smaller) spikes distally and some flat or rounded processes subbasally (the latter absent in relatives) (cf. Fig. 80 ). Filum ( Figs 80, 81 ) formed by homogenous elongate and curved sclerite as in congeners and having apex of filum ( Fig. 79 ) shortly lanceolate, with small subapical denticle and reduced distal membranous lobe. Ejacapodeme slightly bigger than in relatives, with longer digitiform projection ( Fig. 81 ).

Female unknown.

Discussion. Epischnomyia tkoci sp. nov. is the third species of the genus. Its congeners, viz. E. triarmigera ( Sueyoshi & Roháček, 2003) and E. merzi Roháček, 2009 are closely related and very similar both in external and genital characters (cf. ROHÁČEK 2009) but this new Chinese species differs distinctly from both of them with its distally strongly tapered gonostylus having 2 small denticles on apex, differently formed medandrium, more setose pregonite, aedeagal part of folding apparatus with elongate robust spines on both sides, saccus armed with 4 (but 3 smaller) spikes distally and some additional subbasal projections and some other details in the male internal genitalia.

Epischnomyia tkoci seems to be generally darker than both relatives but considering the known colour variabi- lity, particularly in E. merzi (see ROHÁČEK 2009: 84), this dissimilarity is of limited diagnostic value, particularly as regards the dark form of E. merzi . The only distinct external difference has been found in the specialized chaetotaxy of the male hind femur where E. tkoci has more and very densely arranged thickened setae in the distal half (see Fig. 71 ).

Etymology. The new species is named in honour of my friend Michal Tkoč (NMPC), a keen dipterist and specialist in Platypezidae , who collected this species in Sichuan.

Biology. Poorly known. The holotype was swept from rich herbaceous vegetation on a forested slope (see its habitat in Fig. 72 ) in a montane valley (2050 m), on 24 June (detailed information from M. Tkoč, personal communication, 2018).

Distribution. China: Sichuan.

Figures

Figs 68–72. Epischnomyia tkoci sp. nov. and its habitat. 68–71 – E. tkoci sp. nov., male holotype (China: Sichuan): 68 – head, dorsolaterally; 69 – holotype before dissection, laterally (body length 2.9 mm); 70 – f1 and t1, posteriorly; 71 – distal half of f3, posteriorly; 72 – habitat of E. tkoci in the type locality. Photos by M. Tkoč.

Figs 99–106. Anthomyza sulphurea sp. nov., male paratype (China:Yunnan).99–100 – external genitalia (99 – caudally; 100 – laterally); 101 – hypandrial complex, laterally; 102 – gonostylus, lateroventrally (widest extension); 103 – basal end of phallapodeme, dorsally; 104 – aedeagal complex, laterally; 105 – transandrium, caudally; 106 – apex of filum, ventrally. Scales = 0.1 mm.

Figs 73–81. Epischnomyia tkoci sp. nov., male holotype (China: Sichuan). 73–74 – external genitalia (73 – caudally; 74 – laterally); 75 – right wall of aedeagal part of folding apparatus;76 – gonostylus, subcaudally (widest extension); 77 – hypandrial complex (right side), laterally; 78 – transandrium, caudally; 79 – apex of filum, sublaterally; 80 – distiphallus, ventrally; 81 – aedeagal complex, laterally. Scales = 0.05 mm (Figs 76, 79), 0.1 mm (others). For abbreviations see p. 37.