Ortochile Latreille

SCOTT E. BROOKS, 2005, Systematics and phylogeny of Dolichopodinae (Diptera: Dolichopodidae), Zootaxa 857, pp. 1-158 : 80-83

Genus Ortochile Latreille

( Figs. 19 A–E)

Ortochile Latreille, 1809: 289 . Type species Ortochile nigrocoerulea Latreille [Palaearctic], by monotypy.

Orthochile incorrect subsequent spelling by Latreille, 1825: 489, followed by Berthold, 1827: 497, 587. Erroneously listed as an emendation by Neave, 1940: 469.

Recognition. Species of Ortochile can be recognized by their greatly elongated mouthparts, which are longer than the height of the head.

Description. Head: Vertex not distinctly excavated, 1 pair of strong vertical setae, stronger than postverticals. Frons about 2.3 x wider than high, sides weakly convergent anteriorly. Face slightly broader in female, sides distinctly convergent below, lower portion of face produced at boundary with clypeus. Clypeus produced along upper margin, weakly rounded below, not reaching lower eye margin. Palp and proboscis greatly elongated. Palp shorter than labium, rounded apically with weak setae on outer surface, lacking distinct apical seta. Labrum­epipharynx, epipharyngeal armature and hypopharynx narrow and elongate, hypopharynx tapering to a fine point apically. Labium about 1.2–1.6 x as long as head is high, labellum divided medially into narrow, subtriangular lobes. Antenna: Scape subconical, with distinct acute medioventral process; pedicel short; first flagellomere ovoid to subtriangular; arista dorsal to subapical, 2­segmented, distal segment with very short pubescence. Postvertical setae stronger than uppermost pair of postoculars.

Thorax: Acrostichals weakly developed, biserial anteriorly, irregular or absent posteriorly; 6 dorsocentrals, fifth offset medially; 1 strong outer posthumeral, 1 weaker inner posthumeral; 2 notopleurals; 1 presutural; 1 sutural; 2 supraalars; 1 postalar. Upper part of propleuron with a cluster of fine hairs; lower part of propleuron with 1 strong prothoracic seta and a few fine hairs; pleural surface in front of posterior spiracle bare; metepisternum bare. Scutellum with 1 strong inner seta and 1 weak outer seta on lateral margin.

Legs: Pulvilli developed normally on all legs. Foreleg: Basitarsus usually with 3–4 distinct ventral setae. Midleg: Femur with 1 anterior preapical seta, with or without distinct posterior preapical seta in addition to terminal posteroventral preapical; fifth tarsomere sometimes dorsoventrally flattened (e.g., O. soccata Loew ). Hindleg: Coxa with strong lateral seta near middle; femur with 1 anterodorsal preapical seta, sometimes with distinct anteroventral preapical seta; basitarsus subequal to slightly shorter than second tarsomere, with or without distinct basiventral seta, male with small dentiform process posterobasally.

Wing: Gray to brownish, usually darker anteriorly. R2+3 nearly straight; R4+5 curved posteriorly in distal section; distal section of M beyond crossvein dm­cu with weak anterior bend before middle, convergent with R4+5, ending well before wing apex, close to apex of R4+5 (very close in O. soccata ); crossvein dm­cu distinctly shorter than distal section of CuA1.

Abdomen: Subconical. Male: T6 bare, well­developed; S2 and S3 unmodified, S4 emarginate posteriorly, S5 mainly membranous, with a pair of weakly sclerotized longitudinal bands; S6 Y­shaped, fused to T6 posterolaterally, with narrow base extending anteromedially to middle of S5; segment 7 forming well­developed peduncle; S8 teardropshaped, setose. Hypopygium ( Fig. 19 A–C): Epandrium longer than wide, ovoid with rounded anterior margin in lateral view, symmetrical, laterally compressed, especially in anterior half; foramen positioned laterally, slightly before middle, well­separated from base of cerci; basiventral lobe weakly developed, with small dentiform process immediately anterior to weak basiventral epandrial seta; apicoventral epandrial lobe well­developed, subrectangular in lateral view with expanded apex, with 1–2 lateral and 2 apical setae, medial surface with well­developed mediodorsal ridge. Surstylus bilobed. Ventral lobe laterally flattened, subquadrate, narrowed apicoventrally, with strong seta on inner surface and stout apical seta. Dorsal lobe digitiform, slightly longer than ventral lobe. Postgonite with anteroventral portion weakly sclerotized; posterodorsal portion welldeveloped, simple, tapered distally and curved ventrally. Proctiger brushes absent. Cercus subtriangular with long marginal and apical setae. Hypandrium simple, trough­like, as long as apicoventral epandrial lobe, fused to epandrium laterally near basiventral epandrial lobe/seta; hypandrial apodeme present, well­developed; hypandrial arms connected to hypandrium. Sperm pump small, spherical; ejaculatory apodeme well­developed, weakly flattened laterally; basal sclerite of sperm pump heavily sclerotized, V­shaped in dorsal view. Phallus long and slender with preapical fin­like projection. Female ( Fig. 19 D, E): Terminalia elongate, longer than abdomen. T6, T7, S6 and S7 undivided; T8 and S8 divided medially, tergite and sternite not fused anterolaterally. Furca present, elongate and narrow. T10 not divided, each side with 3 long apically flattened and rounded spines and a small inner medial spine or seta ( Fig. 19 E). Upper lobe of cercus with 1 long ventral preapical seta and 1 long apical seta.

Geographical Distribution. Ortochile is known from the western Palaearctic region, including Europe, Turkey, Israel and North Africa ( Negrobov 1991; Parvu 1997).

Phylogenetic Relationships. This genus is most closely related to the clade including Poecilobothrus , Parahercostomus and Grichanov’s (1999a) Afrotropical Hercostomus species group 1 based on characters of the male and female genitalia.

Remarks. Unlike most dolichopodine genera, adults of Ortochile are associated with flowers (in particular those of the family Asteraceae ) and two species are known to feed on nectar (Dyte unpublished manuscript). During genitalic dissections, I found pollen grains in the rectum of both O. nigrocoerulea and O. soccata , further supporting the hypothesis of flower feeding habits of this genus.

Nectar­feeding is also known in some species of Hercostomus , including H. germanus and H. nigripennis (Dyte unpublished manuscript), the latter of which possesses elongated mouthparts, which are similar to, but distinctly shorter than those of Ortochile . As noted by Dyte, these species have very similar male genitalia and appear to be closely related to each other. My studies of the male genitalia indicate that these species are part of the sister group to Ortochile based on the possession of preapical lateroventral lobes on the postgonite (character 59:1). As noted by Dyte, Hercostomus conformis , H. morenae (Strobl) , H. pandellei and H. rostellatus also appear to be closely related to H. germanus and H. nigripennis based on the genitalic illustrations and descriptions in Parent (1938).

Material Examined. Ortochile nigrocoerulea Latreille , [PA]: 2ɗ, 6Ψ ( CNC); Ortochile soccata Loew , [PA]: 2ɗ, 2Ψ (LEM); Ortochile unicolor Loew , [PA]: 5ɗ, 5Ψ ( USNM).

Figures

FIGURE 19. Ortochile nigrocoerulea: (A) Male genitalia, left lateral view (external); (B) Male genitalia, left lateral view (internal); (C) Male genitalia, ventral view (postgonite, surstylus and cerci not shown); (D) Female genitalia, left lateral view; (E) Female genitalia, dorsal view.