Merziella, Stuke, Jens-Hermann, 2014

Stuke, Jens-Hermann, 2014, A new genus of Conopidae from Europe (Diptera), Zootaxa 3795 (4), pp. 472-482 : 472-480

Description of Merziella gen. nov.

(figs 1–19)

Material examined. 2♂ 1♀ no date, "Schlesien", leg. Letzner, coll. Senckenberg Deutsches Entomologisches Institut, Müncheberg ( SDEI); BULGARIA: 1♀, 11.–25.vi.1998, Sofia, University Experimental Farm, c. 600 m, leg. P. V. Atanassova, coll. Universiteit van Amsterdam, Instituut voor Taxonomische Zoologie, Zoologisch Museum, Amsterdam ( ZMAN); GERMANY: 1♂, 15.vii.1889, Brandenburg, Fürstenberg i. M., leg. Konow, coll. SDEI; GREECE: 1♂ 1♀, 23.vi.2004, Lesbos, 3.8 km SSE Agiasos, 760 m, 39°3’17’’N 26°23’50’’E, chestnut forest, at Crepis spec., leg. M. Kapsali, coll. Jens-Hermann Stuke, Leer ( PJHS); ITALY: 1♂, 20.vii., Rom, Arsoli, collector unknown, coll. PJHS; ROMANIA: 1♂, 16.vii.1912, Dacia, Mehadia, leg. Oldenberg, coll. SDEI; 1♂, 18.vii.1912, ditto, coll. PJHS.

Diagnosis. The monotypic genus Merziella can easily be identified as belonging in the subfamily Myopinae by the following suite of characters: ocelli present; filiform arista either dorsally or subapically on basal flagellomere; face lacking obvious carina; proboscis doubly bent, with a long labellum; lack of a subcostal-radial-crossvein sc-r. Within the Myopinae Merziella is distinguished from all other genera by the obviously elongated proboscis (figs 1, 5) and the characteristic male postabdomen with its unique long sclerotised postgonite evagination (figs 15: poe, 18: poe, 19: poe) and ‘window’ in the anteriorly directed sheath of the hypandrium (fig. 18: whys). The combination of characters described in the key below distinguishes Merziella from other Myopinae in greater detail.

Type-species. Merziella longirostris ( Lyneborg, 1962) , herewith designated.

Etymology. The genus Merziella is derived from "Merz" and the diminutive ending "-iella". The patronomy is dedicated to Dr. Bernhard Merz (Geneva) to whom I am very grateful for his support throughout the period that I have been working with acalypterate flies. Bernhard Merz´s contributions to the knowledge of several acalypterate families cannot be overestimated. The name Merziella is to be treated as masculine.

Description. Head. Antenna (figs 3–4) with arista situated dorsally on the basal flagellomere. Arista with two obvious aristomeres, with inconspicuous rudimentary third aristomere at base (fig. 4: bar), apical aristomere long, broad basally, becoming abruptly narrower in the apical third. Pedicellus about twice as long as maximum width, completely covered with black setae with the exception of the ventral surface. Basal flagellomere short, slightly longer than high, and shorter than the pedicellus; rounded dorsally, without membranous area. Basal flagellomere without bristles. Lunule between bases of antennae and ptilinal suture, more or less completely invaginated. Eyes brown, without ommatrichia, facets all of about the same size. Posterior margin of eye convex, without any indentation. Gena below eye moderately broad (ratio of maximum eye height: height of gena below eye = 4.0–6.3). Ocellar tubercle with three distinct orange-brown ocelli. Ocellar triangle evident, not reaching further forward than half the length of the frons (fig. 2: otr). Vertex not developed. Frons longer than broad, parallel-sided, not projecting above the eyes (fig. 2). Frons with silver dusting laterally at the eye margin in posterior view, and silver dusting all over in anterior view. Black hairs over entire frons which might include frontal and orbital setae, but these usually not distinct. No frontofacial spots. Face slightly silver dusted, facial grooves shiny. Gena and facial ridge with scattered black hairs. Distinct facial grooves reaching to a small, ventral facial tubercle. Facial grooves broader than maximum width of an antenna. Facial carina absent. Ptilinal suture stretching beneath the antennal bases. Mouth opening not tapering dorsally. Adjacent to posterior margin of eye there is a stripe of dense silver dusting. Postgena widened and therefore separated from the small occiput. Postgena distinctly silver dusted, the remaining postcranium hardly dusted to shining. Postgena with long white hairs, occiput with long black hairs. No hairs on a narrow area adjacent to the eye margin. Median occipital sclerite ventrally with scattered hairs. Bottom portion of postcranium distinctly separate and without hairs. Proboscis brown to black. Indistinct brown spot between frontoclypeal membrane and mouth edge. Frontoclypeal membrane narrow, broadened basally, light yellow and distinctly separate from brown clypeus. Palp long (fig. 7: pl) brown to black, hardly widening distally, covered with long white hairs. Proboscis doubly bent (figs 1, 5). Labium about 1.5 times as long as head-length, projecting out of the mouth opening, hardly thickened at base. Labellum (fig. 7) as long as labium, divided only at apex, slightly narrower than adjacent haustellum and covered with scattered hairs. Labrum short. Head with distinct ocellar seta (oc), postocellar seta (poc), medial vertical seta (m vt) and sometimes with less distinct lateral vertical seta (l vt). Frontal and orbital setae are difficult to pick out, but may be more obvious in some specimens.

Thorax. Black, dense silver to golden dusted all over. Anteriorly on the scutum with two more or less distinct narrow less-dusted submedial stripes reaching to the indistinct transverse suture. These stripes are bordered by a pair of distinct, broad, less-dusted sublateral stripes or patches. Anepisternum less dusted ventrally and katepisternum less dusted anteriorly. Presternum only a narrow sclerotised strip. Basisternum narrow, narrowing to tip, with several long black hairs apically. Proepisternum with several black hairs ventrally and without hairs dorsally. Mediotergite convex, hairless, about as long as scutellum. Subscutellum inconspicious. Scutellum covered with long black hairs, with two pairs of scutellar bristles. Lateral scutellar bristles slightly smaller and therefore less distinct. Scutum with long black hairs, about as long as tibia diameter, posterior hairs at least twice as long as anterior hairs. 1 postpronotal, 2 notopleural, 2–4 supra-alar, 2–4 postalar, and 0–1 prescutellar dorsocentral setae. Setae hard to detect between the long hairs and readily confused. Several black bristles and hairs posterodorsally and ventrally on katepisternum. Metakatepisternum may have a few bristles. Anepisternum and anepimeron hairless and without bristles. Wing (figs 8–9) with membrane uniformly hyaline and completely covered with microtrichia. No subcostal-radial crossvein sc-r. Radial-medial-crossvein r-m complete, basalmedial-cubital-crossvein bm-cu incomplete. Radius R1 and subcosta Sc terminate together in costa C, well before end of radius R2+3 (fig. 9). R1 touches subcosta where it terminates in the costa. Costa not thickened at insertion of Sc+R1 (fig. 9). Radius R4+5 with shallow and even curve in distal section directed towards wing tip. Radial cell r4+5 open, i.e., vein R4+5+M not expressed. Cubital cell cup elongated, distinctly longer than vein A1+CuA2, and with a point distally (i.e. cubitus CuA2 and anal vein A1 meet at an acute angle). Vein A1+CuA2 reaching hind margin of wing only indistinctly. Cubital vein CuA1 and crossvein bm-cu distinctly separated. Upper and lower calypters white, upper calypter with long white hairs on margin. Alula broad, length about twice width, with long hairs on posterior margin. Venae spuria pronounced in cubital cell cup and indistinct in cubital cell cua1 and discal medial cell dm, but not developed in radial cell r4+5. Haltere yellow to light brown, with a slightly darker brown base. Base and stem of haltere each with areas of sensillae. Knob of haltere with isolated indistinct light brown hairs. Leg coloration variable, almost completely orange-brown, with only the tarsi more or less black to almost completely black. Legs with more or less obvious silver dusting. Posterior surfaces of fore and middle tibiae without obvious dusted fields distally. Legs all with long, semiadpressed or erect black hairs. Areas of dense golden brown to black hairs ventrally at tip of fore tibia and ventrally and posteriorly at tip of hind tibia. Middle femur posteriorly without regularly arranged long hairs, but with a few longer hairs. Hind femur dorsally with few outstanding long hairs. Preapical bristles dorsally on tibiae. Fore and middle tibiae basally on ventral surface with a more or less indistinct row of short, thick adpressed black bristles. All femora distally on ventral surface with two parallel rows of short, thick black bristles. Fore coxa with 1–3 black bristles which are stronger than the surrounding scattered hairs. Middle and hind coxae with several distinct strong lateral bristles which are about as long as diameter of basal hind tibia. Hind femur not obviously thickened in basal half. Pulvilli yellow-whitish. Claws yellowish white with distinct black tips. Empodium whitish yellow. Empodium about as long as pulvilli. Abdomen. Ground colour black. ♂ abdomen covered almost completely with white hairs only, ♀ abdomen with white hairs on tergites 1–3 and black hairs on the remaining tergites. ♂ abdomen slightly golden dusted all over with the exception of a shining posterior area on the protandrium (sternite 8 sensu Schneider 2010) and the epandrium. ♀ abdomen silver dusted all over with the exception of the shining syntergite 7+8. In posterior view a more or less broad black central area can be seen on the tergites. ♂ abdomen with 5 tergites. Tergite 1 with white hairs laterally which are shorter than the lateral hairs on tergite 2. Tergite 2 without lateral bulbous projection or obvious lateral hair tufts but with slightly longer hairs than those laterally on tergite 3. Tergite 2 shorter than broad. Tergite 3 not widened posteriorly. Sternites 1–5 present, sternites 1 and 2 fused to some extent but still distinguishable. Tergite 5 and sternite 5 distinctly separate. Sternite 4 slightly broader than long and obviously narrower than sternite 5, with several long black hairs. Sternite 5 apically with a field of thick black bristles and long hairs. Protandrium not projecting over the epandrium. Shining sternite 8 hardly delimited from the protandrium but occupying about half of the protandrium. Ventrally the lateral edges of the protandrium are fused by a narrow strip. Paired cerci distinct, completely sclerotised and covered with hairs. Epandrium (figs 13–14) not fused behind cerci and broadly separated. Hypoproct slightly sclerotised and not projecting out of epandrium. Posterior surstylus slightly elongated, and rounded apically; anterior surstylus inconspicious. No strong black bristles at base of surstyli. Subepandrial plate not sclerotised. No dorsal hypandrial bridge evident (fig. 19). No hypandrial lobe evident. Hypandrium ends in a broad hypandrial arm with a large excision (fig. 16). Hypandrial membrane without obvious dense microtrichia

FIGURES 8–9. Wing of Merziella longirostris (Lyneborg) . 8. Wing. 9. Costa and adjected veins. Abbreviations: r-m, radialmedial crossvein; R1, radius R1; R2+3, radius R2+3; SC, subcosta.

(fig. 16: hym). Hypandrium sheath not fused dorsally; apically without obvious evagination and without any teeth or bristles, dorsomedially without a notch. Hypandrium sheath with a large ‘window‘ (fig. 18: whys). Left and right postgonites distinct, similar to each other and without hooks or teeth. Obvious postgonite evagination completely sclerotised and large (figs 15: poe, 18: poe, 19: poe). There is an outer plate which is recurved when the phallus is directed forward, and directed anteriorly when the phallus is retracted (figs 18: src, 19: src). A ring sclerite is developed but not evident (fig. 19: rs). Epiphallus distinct, covered with microtrichia (fig. 18: epp). Distiphallus long, almost as long as the epandrium, covered with blunt microtrichia and without any evaginations, but with indistinct sclerotised dorsolateral strips which are connected with the ring sclerite (fig. 18: dp). Phallus apodeme longer than hypandrium arm. Ejaculatory apodeme elongate, distinctly sclerotised, attachment to sperm sac evident (fig. 17). ♀ abdomen has its maximum width at segment 2. Sternites 1–2 fused but still distinct. Sternites 3–4 slightly protuding ventrally, only the posterior parts of the sternites conspicious. Tergite 5 and sternite 5 separate, the latter with a slightly projecting theca below. Anterior surface of theca lacking hairs. Apical half of posterior surface with close-set, short blunt spicules, entirely arranged in horizontal lines (fig. 10). Anterior part of Sternite 5 (fig. 10: aS 5) obviously elongated and deflexed. Sternite 6 almost completely covered with short blunt spicules which are entirely arranged in horizontal lines (fig. 11). Posterior part of sternite 6 is nearly bent at a right angle to the middle part of the sternite. Tergite 7 is distinctly bent ventrally, without a longitudinal gap, and with a hardly protuding tooth in the middle of the posterior margin. The area between the sides of syntergite 8+9 is completely sclerotised, and there is no distinct sternite 8. Lateral tooth on syntergite 8+9 distinct, its base elongated anteriorly. Beneath the tip of the tooth there is a strong sclerotisation of syntergite 8+9. Sternite 9 covered with strong, blunt black bristles and with long hairs on posterior margin. Paired cerci obvious. Sack-like ventral protrusion of vagina with a distinct annular sclerotisation (fig. 12: ave) and covered with black bristles over a broad area distally (fig. 12: bve). No obvious sclerotisation at base of either the accessory glands or spermathecal ducts. No obvious dorsal sclerotisation on sack-like ventral protrusion of vagina. Two pairs of spherical spermathecae, the spermathecal ducts fusing shortly after leaving the spermathecae. Spermathecal ducts not sclerotised at junction with spermathecae.

Distribution. The monotypic genus Merziella is widely distributed in the Palaearctic region from Belgium in the West to Kazakhstan and the Altai in the East, with records from Armenia ( Chvála & Smith 1988; Zimina 1976), Austria ( Franz 1989; Lyneborg 1962), Belarus ( Zimina 1976), Belgium ( Tomasovic 2000), Bulgaria (this paper), Germany ( Kormann 1983; Kormann & Hassler 1993; this paper), Greece ( Stuke et al. 2012; this paper), Hungary ( Tóth 2007), Italy ( Mei 2000; Smith 1967; this paper), Kazakhstan ( Zimina 1968), Poland ( Bankowska 1974, 1979, 1981; Chvála 1965), Romania ( Chvála & Weinberg 1970), Russia ( Chvála & Smith 1988; Zimina 1976), Ukraine ( Zimina 1976) and Turkey ( Koçak & Kemal 2013). Merziella longirostris is seldom collected with any frequency anywhere within its distribution.

Biology. Zimina (1968) reports Apis mellifera L. as a host of Merziella longirostris . Recorded flower visits for M. longirostris include Crepis sp., Taraxacum sp. and Matricaria recutita L. ( Stuke et al. 2012).

Identification. A key to the genera of Myopinae is provided below. The only known species of Merziella has previously been described, or included in keys, as T. longirostris , for example by Lyneborg (1962), Chvála (1965), Smith (1967), Bankowska (1974, 1979, 1981), Zimina (1988, 2000), Rivosecchi (1996) and Tomasovic (2000).