Nothybidae

Lonsdale, O. & Marshall, S. A., 2016, Revision of the family Nothybidae (Diptera: Schizophora), Zootaxa 4098 (1), pp. 1-42 : 5-10

Diagnosis of Nothybidae

Elongate-bodied and long-legged flies with anterior portion of thorax strongly produced ( Figs 1 –10); body length 5.5–15.0mm; wing length 5.0–10.4mm. Subscutellum large and subconical, reaching or (usually) greatly exceeding scutellar apex ( Fig. 12 ). Colour variable but usually orange to brown with abdomen darker in part, and with pigmented stripes and spots on head and thorax; head with three dark velvety patches. First flagellomere slightly to distinctly angled, narrow, twice as long as wide; pedicel with dorsal seam. Frons and back of head rounded; ocellar tubercle slightly separated from vertical and postocellar setae. Vibrissa and ocellar setae absent. One dorsocentral seta. Katepisternal seta absent. Fore tarsus white in part, at least on basitarsomere. Costa unbroken; vein sc complete; cell br open; cell cup mostly or entirely without microtrichia; alula and anal lobe nearly absent; veins R4+5 and M1 parallel to slightly divergent. Female tergite and sternite 7 separate, not forming oviscape (Figs 17–20). Similar taxa: The family most likely to be confused with Nothybidae is Micropezidae , most species of which are also large, slender-bodied, long-legged flies, and many of which resemble nothybids in head chaetotaxy. Some micropezids also have an enlarged subscutellum, and one Australasian-Oriental genus ( Nestima ) is characterized by an inflated subscutellum that resembles that of Nothybidae in exceeding the scutellum. Several Micropezidae have a single similar dark velvety patch on the frons (a single patch is also seen in Megamerinidae and Tanypezidae ). Micropezidae , however, have one or more katepisternal setae, do not have the fore coxae widely separated from the anterior margin of the thorax, lack a precoxal bridge, and have veins R4+5 and M1 convergent. Micropezids also have different male terminalia, usually with a forked posteromedial process on sternite 5 and, unlike Nothybidae , female micropezids, as in other Nerioidea, have tergite and sternite 7 fused to form a conical oviscape.

Definition of Nothybidae

Colour: Setae mostly or entirely black. Usually yellowish-orange in base colour, abdomen often darker; sometimes dark brown with smaller orange patches; often with brown mottling or ill-defined stripes. Most of thorax and abdomen covered with light pruinosity that is often greyish ( Fig. 6 ) but sometimes thicker and black (Fig. 7). First flagellomere usually black apically, face usually with dark brown to black spot often flanked or surrounded by silvery tomentosity ( Fig. 38 ). Frons with three black velvety patches including one comma-shaped pair anterolaterally and one rounded/subquadrate patch behind ocelli; ocellar tubercle black/dark brown ( Fig. 11 ). Thorax sometimes with pigmented stripes, always with purplish-white pruinose iridescent stripes that are most prominent on postpronotum (sometimes only visible at certain light angles) ( Figs 3 , 5 , 9). Apices of femora, tibiae and tarsi usually dark; fore tarsus white, at least at base. Wing often lightly infuscated past dm-cu, sometimes with discrete infuscated bands around veins, and often with darker pigment marginally; usually with transverse brown band extending from CuA1 to costa at level of dm-cu, past which is clouded region often enclosing two or three clear and strongly iridescent spots in cells r2+3, r4+5 and m1 ( Fig. 69 ); medial region of wing often with faint iridescence (spots and iridescence absent in N. longicollis , Fig. 67 ); sometimes with subapical cloud on CuA1 and around r-m. Halter white to yellow with base usually partially brown and knob sometimes faintly brownish. Abdomen with velvety patch on at least tergite 5 (as in Fig. 40).

Chaetotaxy: 1 inner vertical; 1 outer vertical (approximately 3/5 length inner vertical); 2 strong reclinate fronto-orbitals, anterior seta slightly inset; 0 ocellars; 0 postocellars; vibrissa absent. 0 presutural intra-alars; 0 postpronotals; 1 notopleural (anterior seta absent); 1 posterior supra-alar; 1 postalar; 0 posterior intra-alars; 1 dorsocentral; 0 acrostichals; 1 lateral scutellar, 1 apical scutellar; 0 proepisternals; 1 anepisternal; 0 katepisternals. Back of head with lateral row of weak postocular setae. Mid coxa with strong lateral seta. Mid tibia with 1 strong ventroapical seta.

Pattern of setulae and minor setae as follows: pedicel with minute scattered medial and marginal setulae, one large dorsal seta and several enlarged ventral setae; dorsal half of face, parafacial and anterolateral region of frons minutely setulose; palpus with stout scattered setulae; prementum with minute setulae and one pair of short and long setae; notopleuron with small cluster of setulae around posterior tubercle and with larger, sparser patch anteromedially; remainder of scutum with setulae in usually distinct patches with gap between rows just outside dorsocentral row ( Fig. 13 ); setulae lateral to dorsocentral row postsuturally in several rows that extend to supra-alar seta, and presuturally in two to several rows that are sparser to absent; setulae on and between dorsocentral rows divided into two bands presuturally (separated by a narrow gap), the lateral section of which is sometimes united with those setulae lateral to dorsocentral row, and the medial section of which is sometimes split along midline anteriorly; scutellum with irregular row of setulae along lateral margin; katatergite with setulae along posterior margin and anatergite with setulae medially; anepisternum with setulae along posterior margin dorsally; katepisternum with short setulae scattered ventrally; subalar sclerite and proepisternal lobe with scattered setulae; longer setulae present anteroventrally on fore coxa (lateral one or two larger) and mid coxa (larger towards centre); hind coxa with scattered setulae; femora with rows of setulae (setulae smaller ventrally and midline bare) that become scattered dorsoapically; tibiae and tarsi with setulae in rows with dense ventrobasal patch on basitarsomeres. Abdominal tergites and sternites with scattered setulae.

Head. Suborbicular, ocelli apparently near midpoint of head. Antenna angled with pedicel cap-like and with dorsal seam, arista bipectinate; first flagellomere slightly longer than wide. Ocellar tubercle small and near posterior margin of ocellar triangle, which is long, narrow with sides subparallel and slightly converging anteriorly. Face well sclerotized, convex; often with glossy, dark brown to dark yellow protrusion/tubercle ventromedially that is surrounded by silvery tomentosity ( Fig. 38 ) ( N. longicollis with dark subquadrate spot, without glossy patch; Fig. 11 ). Gena and postgena very narrow. Clypeus large, produced; prelabrum widest past midpoint; palpus narrow, subcylindrical ( Figs 15, 16 ). Head with broad post-ocellar concavity and bulge above foramen.

Thorax. Extended anteriorly, displaced from base of fore coxa (especially pronounced in N. longicollis , Figs 1– 4 ); postpronotum elongate. Posterolateral corner of notopleuron with small tubercle at base of seta. Scutellum relatively long, flat dorsally and laterally. Subscutellum conical, larger than scutellum ( Fig. 12 ). Posterodorsal margin of katepisternum abruptly recessed. Proepisternum extending into lobed plate anteriorly. Katepisternum and meron partially fused. Greater ampulla absent. Coxopleural streak sometimes visible. Precoxal bridge present, very large and broad, fused to teardrop-shaped prosternum ( Fig. 14 ); postmetacoxal bridge absent. Spiracles broadly ovate, fringed with short hairs.

Wing. ( Figs 67–78 ) Length 5.0–10.4mm. Alula and anal lobe vestigial. Costa unbroken. Vein sc complete. A1+CuA2 reaching wing margin when present. Cell cu p and bm short. Cell br open. Cell bm open anterodistally. Basal cells and cell cu p without microtrichia. R2+3 to CuA1 slightly diverging. CuA1 reaching wing margin ( Fig. 67 ). CuA2 slightly curved. Wing with deep basal “pocket” (i.e. bulging ventrally) occupying most of wing base posterior to stem vein. Upper calypter linear, pubescent; lower calypter vestigial.

Legs. Long and slender; tarsus elongate, similar in length to tibia. Fore legs shifted posteriorly, distant from head. Hind basitarsus with slight basal swelling, similar to Tanypezidae .

Abdomen. Relatively stout, subcylindrical, slightly constricted at base and gradually tapering apically. Pregenitalic sternites long and narrow, except sternite 1 wider than long (Fig. 18) and sternite 6 relatively short. Spiracles 1–6 in membrane, male 6th spiracles associated with weakly sclerotized margin of tergite 6; 7th spiracle sometimes absent.

Female genitalia. Tergite and sternite 7 separate, not forming oviscape (Figs 17, 19, 20). Female terminal segments relatively short, wider than long; tergite 8 longitudinally divided basally (Fig. 19); sternite 8 entirely divided (Fig. 20); tergite 10 and sternite 10 small, subtriangular. Two small black spherical spermathecae on separate long, unpigmented, distally narrowed ducts; ducts narrowly constricted at base and arising on a short common duct or process of the bursa copulatrix (Fig. 21). Ventral receptacle of dissected females with transversely wrinkled stem expanding into bent, pigmented apical lobe with small membranous sac emerging subapically.

Male genitalia. ( Figs 96–101 ) Sternite 7 membranous, very short, sometimes not evident except for a pair of widely separated sensory setulae. Sternite 8 dorsal, tapered laterally, symmetrical. Cercus finger-like or relatively broad, often flat or slightly raised, subconical in N. longicollis . Surstylus long and slender to small and rounded; usually partially to entirely fused with epandrium basally at least on posterior half (free in N. longicollis ), and fused with subepandrial sclerite along inner surface (partially fused in N. longicollis ). Subepandrial sclerite with curved medial plate elevated from inner surface of epandrium, extending ventrally to fuse to inner surface of surstylus (modified in N. biguttatus ). Hypandrium with broad, densely setose lateral plates connected medially with ventrolateral extensions of phallapodeme (separate from phallapodeme in N. longicollis ); often prominent laterally and with outstanding setae. Pregonite well-developed, setose, pointed and covered with minute bumps or microspinules; this structure is here interpreted as the pregonite because of its external articulation with the hypandrium and chaetotaxy, although its position relative to the base of the phallapodeme does suggest the possibility that this structure could instead be the postgonite, which is currently interpreted as absent. Basiphallus subcylindrical with ring-like base, fused to distiphallus, extending posteriorly as reticulate and ill-defined epiphallus. Distiphallus long, flat and ribbon-like with one pair of dark bands extending at least to midpoint; apex often with one pair of clear tubules. Ejaculatory apodeme with clear blade, well-developed stalk with minute cylindrical perforations medially, and well developed asymmetrical base usually enclosing narrow fossa; sperm sac without sclerotizations.

Immature stages

Immature stages of Nothybus are known from two first instar larvae, one reported by J.F. McAlpine (1989) and one found during the current study and figured here, both extracted from the abdomens of N. longicollis specimens from Sabah, Malaysia. McAlpine’s specimen was found in an enlarged oviduct and had its head directed anteriorly. The larva found during the current study occupied the posterior half of the female abdomen, and measured 4.2mm by 0.9mm.

Description. Each segment with dorsal and ventral creeping welts ( Figs 22–29 ); abdominal welts strongly developed with 15–20 loose rows of small spicules, posterior rows strong, anterior rows smaller, middle rows minute. Mandibles (mouth hooks) robust, directed ventrally and apparently working at right angles to an elongate (three times as long as wide) hypopharyngeal sclerite. Parastomal bar robust, triangular, articulating with an elongate (four times as long as wide) anteroventral lobe of the tentaropharyngeal sclerite; tentaropharyngeal sclerite with dorsal cornu relatively narrow and with a strong lobe projecting dorsad over basal third of anteroventral lobe. Anterior spiracular process not visible. Posterior spiracular lobes twice as long as wide but contiguous or fused to form a broad posterior spiracular process, each spiracle (two ovate openings on each lobe) sclerotized and ringed by long hairs; trachea darkly sclerotized from spiracle to base of spiracular lobes.

Figures

FIGURES 1 – 4. Nothybus longicollis (Walker), Borneo, Sabah; 1 – 2: male and female, © M. Ng; 3 – 4: male (?), female © S. Gaimari.

FIGURES 11 – 14. Nothybus longicollis (Walker), male; 11: head, anterior; 12: habitus, right lateral; 13: habitus, dorsal; 14: habitus, ventral.

FIGURES 5, 6. Nothybus absens spec. nov., holotype female, China, © S. A. Marshall. Fig. 7: N. lineifer Enderlein, Sabah, male, © S. Gaimari. Figs 8 – 10: N. sumatranus Enderlein, Vietnam, male, © S. A. Marshall.

FIGURES 36 – 38. Nothybus cataractus spec. nov., holotype male, photos; 36: dorsal; 37: left lateral; 38: head, anterior. FIGURES 39 – 41. N. kuznetsovorum Galinskaya & Shatalkin, non-type male, photos; 39: dorsal; 40: left lateral; 41: head, anterior.

FIGURES 67 – 78. wings, photos; 67: Nothybus longicollis (Walker), with relevant veins listed; 68: N. biguttatus Wulp; 69: N. kempi (Brunetti), with relevant cells listed; 70: N. procerus spec. nov., holotype; 71: N. kuznetsovorum Galinskaya & Shatalkin; 72: N. cataractus spec. nov.; 73: N. lineifer Enderlein, syntype; 74: N. decorus Meijere [syn. nov. of N. lineifer], syntype; 75: N. lineifer, CNC specimen; 76: N. triguttatus Bezzi; 77: N. sumatranus Enderlein, syntype; 78: N. sumatranus, Thai specimen.

FIGURES 15 – 16. Nothybus kuznetsovorum Galinskaya & Shatalkin, mouthparts; 15: left lateral; 16: posterior. FIGURES 17 – 21. N. biguttatus Wulp, female abdomen; 17: left lateral; 18: sternites 1 and 2; 19: segment 7 to cercus, dorsal; 20: same, mostly ventral; 21: internal genitalia. Abbreviations: T—tergite; S—sternite; sp—spermatheca; vr—ventral receptacle.

FIGURES 96 – 101. Nothybus lineifer Enderlein, male abdomen; 96: external components, segment 6 to cercus, left lateral; 97: external components past sternite 8, right posterior; 98: same, anterior; 99: internal components, ventral; 100: same, left lateral; 101: ejaculatory apodeme. Abbreviations: T—tergite, S—sternite.

FIGURES 22 – 30. Nothybus longicollis (Walker), first-instar larva; 22: anterior end, left lateral; 23: same, ventral; 24: habitus, left lateral; 25: habitus, ventral; 26: detail, ventral creeping welts, thoracic segment 2; 27: same, abdominal segment 2; 28: same, terminal segments; 29: venter, detail, thoracic segment 2 to abdominal 3; 30: posterior segment, left lateral.