Sybistroma Meigen
Creators: name: SCOTT E. BROOKS
Publisher: name: Zenodo
Year: 2005
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Diptera
Dolichopodidae
Sybistroma

description: Genus Sybistroma Meigen
(Figs. 30 A–E, 31A–E, 32A–E) Sybistroma Meigen, 1824: 71: Type species: Dolichopus discipes Germar (as “Ahrens”) [Palaearctic], designation by Westwood, 1840: 135 (see “Remarks”).
Hypophyllus Haliday, 1832: 359: Type species Dolichopus obscurellus Fallén [Palaearctic], by monotypy (see “Remarks”).
Ludovicius Rondani, 1843: 43. Type species: Ludovicius impar Rondani [Palaearctic], by monotypy. syn. nov.
Nodicornis Rondani, 1843: 46. Type species: Nodicornis wiedemanni Rondani [Palaearctic], by monotypy [= Sybistroma nodicornis Wiedemann in Meigen, 1824: 72]. syn. nov.
Haltericerus Rondani, 1856: 143. Type species: Ludovicius impar Rondani [Palaearctic], by original designation. syn. nov.
Nemospathus Bigot, 1859: 215, 228. Type species: Sybistroma dufouri Macquart [Palaearctic], by monotypy. syn. nov.
Osodostylus: Bigot, 1859: 215, incorrect original spelling of Ozodostylus Bigot, 1859 by revision of Evenhuis and Pont (2004: 43).
Ozodostylus Bigot, 1859: 225. Type species: Sybistroma nodicornis Wiedemann in Meigen (as “Macq.”) [Palaearctic], by original designation. syn. nov.
Dasyarthrus Mik, 1878: 5. Type species: Gymnopternus inornatus Loew [Palaearctic], by original designation. syn. nov.
Spathitarsis Bigot, 1888a: xxiv [1888c: xxiv]. Type species: Dolichopus discipes Germar (as “Ahrens”) [Palaearctic], by original designation.
Hyppophyllus, incorrect subsequent spelling by Bigot, 1890: 276.
Hyphyllus, incorrect subsequent spelling by Becker, 1917: 255
Hemospathus, incorrect subsequent spelling by Bigot, 1888a: xxiv, 1888c: xxiv
Ludovicus, incorrect subsequent spelling by Bigot, 1859: 218
Paecilobothrus incorrect subsequent spelling by Bigot, 1890: 294
Spatiotarsus incorrect subsequent spelling by Bigot, 1890: 263
New Combinations and Transfers: The following new combinations are hereby established: Sybistroma acutatus (Yang, 1996b) comb. nov. (Ludovicius); Sybistroma apicicrassus (Yang & Saigusa, 2001a) comb. nov. (Ludovicius); Sybistroma apicilarius (Yang, 1999a) comb. nov. (Ludovicius); Sybistroma biaristatus (Yang, 1999a) comb. nov. (Ludovicius); Sybistroma biniger (Yang & Saigusa, 1999) comb. nov. (Ludovicius); Sybistroma bogoria (Grichanov, 2004) comb. nov. (Ludovicius); Sybistroma brevidigitatus (Yang & Saigusa, 2001a) comb. nov. (Ludovicius); Sybistroma crinicauda (Zetterstedt, 1849) comb. nov. (Dolichopus); Sybistroma curvatus (Yang, 1998c) comb. nov. (Ludovicius); Sybistroma digitiformis (Yang, Yang & Li, 1998) comb. nov. (Ludovicius); Sybistroma dorsalis (Yang, 1996a) comb. nov. (Ludovicius); Sybistroma emeishanus (Yang, 1998a) comb. nov. (Ludovicius); Sybistroma eucerus (Loew, 1861a) comb. nov. (Haltericerus); Sybistroma fanjingshanus (Yang, Grootaert & Song, 2002) comb. nov. (Ludovicius); Sybistroma flavus (Yang, 1996b) comb. nov. (Ludovicius); Sybistroma golanicus (Grichanov, 2000b) comb. nov. (Ludovicius); Sybistroma henanus (Yang, 1996b) comb. nov. (Ludovicius); Sybistroma impar (Rondani, 1843) comb. nov. (Ludovicius); Sybistroma incisus (Yang, 1999b) comb. nov. (Ludovicius); Sybistroma inornatus (Loew, 1857) comb. nov. (Gymnopternus); Sybistroma israelensis (Grichanov, 2000b) comb. nov. (Ludovicius); Sybistroma longiaristatus (Yang & Saigusa, 1999) comb. nov. (Ludovicius); Sybistroma longidigitatus (Yang & Saigusa, 2001a) comb. nov. (Ludovicius); Sybistroma lorifer (Mik, 1878) comb. nov. (Hercostomus); Sybistroma luteicornis (Parent, 1944) comb. nov. (Hypophyllus); Sybistroma miricornis (Parent, 1926) comb. nov. (Ludovicius); Sybistroma neixianganus (Yang, 1999a) comb. nov. (Ludovicius); Sybistroma qinlingensis (Yang & Saigusa, 2001a) comb. nov. (Ludovicius); Sybistroma sciophillus (Loew, 1869) comb. nov. (Hypophyllus); Sybistroma sheni (Yang & Saigusa, 2000b) comb. nov. (Ludovicius); Sybistroma sichuanensis (Yang, 1998b) comb. nov. (Ludovicius); Sybistroma sinaiensis (Grichanov, 2000b) comb. nov. (Ludovicius); Sybistroma spectabilis (Parent, 1928) comb. nov. (Ludovicius); Sybistroma sphenopterus (Loew, 1859) comb. nov. (Hypophyllus); Sybistroma transcaucasius (Stackelberg, 1941) comb. nov. (Ludovicius); Sybistroma yunnanensis (Yang, 1998a) comb. nov. (Ludovicius). The following species are reassigned to Sybistroma: Sybistroma dufouri Macquart, 1838; Sybistroma nodicornis Wiedemann in Meigen, 1824.
Recognition. Most males of Sybistroma can be distinguished by the following combination of characters: antenna usually modified, with enlarged scape, reduced pedicel, arista 1­segmented and usually with one or more lamellae; wing with weak sinuous anterior bend before middle; hypopygium usually with basiventral epandrial lobes elongate and digitiform with pointed or frayed knob­like tip, shifted ventrally and lying beside hypandrium. Males lacking modified antennae can be distinguished by the possession of greatly elongated and setose apicoventral epandrial lobes. Females cannot readily be distinguished from some species currently placed in Hercostomus.
Description. Head: Sometimes distinctly broader than high in male (e.g., S. dufouri). Vertex more or less flat to weakly excavated, 1 pair of strong vertical setae, stronger than postverticals. Frons about 2– 3 x wider than high, sides weakly convergent anteriorly, male occasionally with dense tuft of velvety hairs between antennal socket and eye margin near frons­face boundary (e.g., S. nodicornis). Face very narrow to broad in male, with sides converging below, broad in female, sides subparallel to weakly converging below; clypeus relatively narrow and flat to weakly produced in male, broad and often strongly produced in female, lower margin straight to weakly emarginate, not reaching lower eye margin. Palp usually small, ovoid, occasionally enlarged and flattened (e.g., S. dorsalis) with fine setae on outer surface, distinct apical seta present or absent. Antenna often modified in male, occasionally inserted just slightly above middle of head in male; scape of male usually slightly to greatly swollen and semi­globular (e.g., S. impar), sometimes unmodified and subconical (e.g., S. obscurellum), medioventral process usually absent or indistinct, sometimes weakly developed; scape of female short, subconical, with well­developed to indistinct medioventral process; pedicel short, often strongly reduced in male (e.g., S. impar); first flagellomere of male variable in size and shape, short and rounded apically (e.g., S. spectabilis) to greatly elongated and acute apically (e.g., S. nodicornis); first flagellomere of female short, usually about as long as wide, rounded or pointed apically; arista of male dorsobasal to apical, 1 or 2­segmented, short to greatly elongated, often with apical lamella, occasionally also with 1–2 medial lamellae, basal segment occasionally elongate (e.g., S. discipes), distal segment weakly pubescent to glabrous; arista of female dorsal to subapical, 2­segmented, distal segment weakly pubescent. Lower postocular setae sometimes weaker. Postvertical setae subequal to distinctly stronger than uppermost pair of postoculars.
Thorax: Acrostichals usually biserial, occasionally extending to base of scutellum (e.g., S. nodicornis), sometimes uniserial (e.g., S. biniger), reduced or absent (e.g., S. flavus); 6 dorsocentrals, fifth pair slightly to strongly offset medially; 1 strong outer posthumeral, 1 weak to indistinct inner posthumeral; 2 notopleurals; 1 presutural; 1 sutural; 2 supraalars; 1 postalar. Upper and lower part of propleuron with fine hairs; lower part of propleuron with 1 strong prothoracic seta; pleural surface in front of posterior spiracle bare; metepisternum usually with 1 or more fine hairs in a cluster or row, occasionally absent (e.g., S. inornatus); katepisternum sometimes with sparse fine hairs (e.g., S. impar, S. eucerus, S. dufouri). Scutellum with 1 strong inner seta and 1 small outer seta on lateral margin, dorsum and posterior margin often with fine setae, sometimes dense (e.g., S. nodicornis).
Legs: Pulvilli usually developed normally on all legs, occasionally somewhat reduced on foreleg of males with enlarged fifth tarsomere (e.g., S. discipes). Foreleg: Femur usually with distinct posteroventral preapical seta; tibia occasionally with distinct anterodorsal comb­like row of strong setae (e.g., S. flavus); tarsus of male sometimes modified (e.g., S. crinipes Staeger, S. discipes, S. eucerus). Midleg: Coxa of male occasionally with elongate, curved marginal setae (e.g., S. eucerus); femur with 1 anterior preapical seta, occasionally with weakly differentiated to distinct posterior preapical in addition to terminal posteroventral preapical seta that is usually present (e.g., S. lorifer, some specimens of S. impar), male sometimes with 2–3 long basiventral setae (e.g., S. flavus), or with row of elongate ventral setae (e.g., S. eucerus); tarsus of male occasionally modified, with distal segments flattened (e.g., S. nodicornis). Hindleg: Coxa with strong lateral seta near or slightly above middle; femur with 1 anterodorsal preapical seta, male occasionally with 1 or more long ventral setae in basal part (e.g., S. miricornis), male sometimes with welldeveloped setae dorsobasally (e.g., S. nodicornis); tibia of male with or without weak dentiform posteroapical process; basitarsus usually shorter than second tarsomere, occasionally subequal, often with a few ventral setae, male with or without weak dentiform or hook­like process posterobasally.
Wing: Brownish to grayish. R2+3 relatively straight; R4+5 with distinct posterior curve in distal section; distal section of M beyond crossvein dm­cu with weak sinuous anterior bend before middle, ending near to distinctly before wing apex; R4+5 and M weakly to distinctly convergent, occasionally subparallel; crossvein dm­cu distinctly shorter than distal section of CuA1.
Abdomen: Subconical, sometimes elongate and slender in male, with tergites long. Male: T5 sometimes with elongate setae on posterior margin; T6 bare; S2 and S3 unmodified to weakly sclerotized and partially membranous; S4 emarginate posteromedially to mainly membranous; S5 mainly membranous, often with weakly sclerotized longitudinal bands; S6 mainly membranous, weakly sclerotized along anterior margin; segment 7 forming well­developed peduncle; S8 subtriangular or heart­shaped to subquadrate, setose. Hypopygium (Figs. 30 A–C, 31A–C, 32A–C) large. Epandrium variable in shape, about 1.5–3.0 x longer than high, often deeply cleft dorsally with cerci arising preapically (Figs. 30 A, 31A); foramen slightly to distinctly dorsolateral, close to base of cerci (e.g., S. obscurellum, Fig. 30 A) or well­separated from base of cerci (e.g., S. nodicornis, Fig. 32 A); basiventral epandrial lobes shifted ventrally and lying beside hypandrium, right and left lobes usually elongate, digitiform and symmetrical, occasionally asymmetrical, basiventral epandrial seta apical usually thickened, knob­like with pointed or frayed tip (Figs. 31 A, 32A), occasionally unmodified (Fig. 30 B); apicoventral epandrial lobe variable, weakly to strongly developed, with or without setae, lobe sometimes greatly elongated, with elongate and/or modified setae (e.g., S. obscurellum, S. impar, Figs. 30 A,C, 31A,C). Surstylus bilobed. Ventral and dorsal lobe more or less digitiform and similar in size, sometimes extremely elongate and slender (e.g., S. obscurellum, S. impar, Figs. 30 B, 31B), dorsal lobe occasionally with frayed seta (e.g., S. nodicornis, Fig. 32 B). Postgonite with anteroventral portion weakly to moderately sclerotized, sometimes distinctly flattened laterally; posterodorsal portion well­developed, slightly to strongly upturned, sometimes elongate (e.g., S. obscurellum, S. impar, Figs. 30 B, 31B), usually with weak lateral projection in basal portion, projection occasionally well­developed and subapical (e.g., S. nodicornis), extreme base occasionally with weak, sometimes bifurcate, projection (e.g., S. discipes, S. eucerus). Proctiger brushes absent. Cercus variable in shape, subrectangular to subtriangular or ovoid, sometimes with distinct notch along apical margin, often with 1 or more thick, modified setae (e.g., S. obscurellum, S. impar, Figs. 30 A, 31A). Hypandrium variable, trough­like (e.g., S. obscurellum, Fig. 30 C), to asymmetrical, sometimes partially membranous and/or with dorsal projections (e.g., S. nodicornis, Fig. 32 B,C), hypandrium laterally flanked by basiventral epandrial lobes and fused with lobes basally; hypandrial apodeme present, well­developed; hypandrial arms connected to hypandrium. Sperm pump small, rounded to subconical; ejaculatory apodeme usually short and rod­like, often upturned, apex occasionally weakly flattened laterally; basal sclerite of sperm pump weakly developed, widening apically, subtriangular to V­shaped in dorsal view. Phallus long, slender and curved (e.g., S. obscurellum, Fig. 30 B) to relatively short and straight, with distinct articulation basally with sperm pump (e.g., S. nodicornis, S. impar, Figs. 31 B, 32B). Female (Figs. 30 D,E, 31D,E, 32D,E): T6, T7, S6 and S7 undivided; T8 divided medially, S8 divided medially or undivided, tergite and sternite not fused anterolaterally; T10 divided medially into hemitergites each bearing 3–5 spines, apex of spines rounded and flattened. Upper lobe of cercus usually with long apical seta.
Geographical Distribution. Sybistroma, as newly defined above (i.e. including species of Ludovicius and Nodicornis), occurs in the Palaearctic (Europe and North Africa to China), Oriental China (Yunnan) and in the Afrotropical realm.
Phylogenetic Relationships. Sybistroma is most closely related to the Hercostomus longiventris lineage based primarily on the position of the basiventral epandrial lobes that are shifted ventrally and laterally flanking the hypandrium (character 63:1).
Remarks. As noted by Chandler (1998: Note 3), Hypophyllus Haliday, 1932 is a junior synonym of Sybistroma Meigen, 1824 because of the designation of Dolichopus discipes Germar, 1821 as the type species of Sybistroma by Westwood (1840: 135). Dolichopus discipes Germar, 1822 is considered to be congeneric with Dolichopus obscurellus Fallén, 1823, the type species of Hypophyllus.
Yang (1996c) described Hypophyllus sinensis Yang from Palaearctic China; however, this species is not congeneric with Sybistroma and clearly belongs to the clade including Poecilobothrus, Parahercostomus and Grichanov’s (1999a) Afrotropical Hercostomus species group 1, based on the possession of preapical dorsolateral lobes on the postogonite. In particular, this species appears to be closely related to Grichanov’s (1999a) Afrotropical Hercostomus species group 1 based on the modified hind tarsus of males; however, until a more extensive phylogenetic analysis of this lineage is completed this species will remain unplaced. For the present I have listed it below as “ Hypophyllus ” sinensis indicating the problematic generic assignment.
Parent (1938) noted that the arista of males of S. miricornis is 2­segmented; however, a more detailed examination (including a slide mount of the arista under a compound microscope at high power) indicates that the arista is actually 1­segmented.
Material Examined. Sybistroma binodicornis Stackelberg, [PA]: 1ɗ (USNM); Sybistroma crinipes (Staeger), [PA]: 3ɗ, 5Ψ (LEM); Sybistroma discipes (Germar), [PA]: 2ɗ (CNC); 1ɗ, 1Ψ (BMNH); Sybistroma dufouri Macquart, [PA]: 2ɗ, 1Ψ (CNC); Sybistroma eucerus (Loew), [PA]: 2ɗ (DEI); Sybistroma flavus (Yang), [PA]: 1ɗ (LEM); Sybistroma impar (Rondani), [PA]: 1ɗ, 2Ψ (DEI); 1ɗ (BMNH); Sybistroma inornatus (Loew), [PA]: 2ɗ, 2Ψ (USNM); 1ɗ, 1Ψ (CNC); Sybistroma lorifer (Mik), [PA]: 1ɗ, 1Ψ (ISNB); Sybistroma maerens Loew, [PA]: 2ɗ, 2Ψ (DEI); Sybistroma miricornis (Parent), [PA]: 2ɗ syntypes, 2Ψ syntypes (DEI); 2ɗ syntypes, 2Ψ syntypes (MNHN); Sybistroma nodicornis Wiedemann, [PA]: 2ɗ, 2Ψ (LEM); 1ɗ (BMNH); 1ɗ (CNC); Sybistroma obscurellum (Fallén), [PA]: 13ɗ, 4Ψ (LEM); 4ɗ, 2Ψ (CNC); Sybistroma setosa Schiner, [PA]: 2ɗ, 1Ψ (DEI); Sybistroma spectabilis (Parent), [PA]: 1ɗ (MNHN); Sybistroma sphenopterum (Loew), [PA]: 1ɗ (LEM); “ Hypophyllus ” sinensis Yang, [PA]: 1ɗ paratype, 1Ψ paratype (LEM).
description: Published as part of SCOTT E. BROOKS, 2005, Systematics and phylogeny of Dolichopodinae (Diptera: Dolichopodidae), pp. 1-158 in Zootaxa 857 on pages 112-120, DOI: 10.5281/zenodo.170753