Strongylophthalmyiidae Hendel, 1917

Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, Zootaxa 4735 (1), pp. 1-177 : 50-53

publication ID	https://doi.org/ 10.11646/zootaxa.4735.1.1
publication LSID	lsid:zoobank.org:pub:BD52DF91-3A7E-46FB-8975-38A67BFBBD61
DOI	https://doi.org/10.5281/zenodo.3679558
persistent identifier	https://treatment.plazi.org/id/BD15296C-6A4D-FFB2-FF1A-F954DBD2A10C
treatment provided by	Plazi
scientific name	Strongylophthalmyiidae Hendel, 1917
status

Treatment

Strongylophthalmyiidae Hendel, 1917 View in CoL View at ENA

( Figs 262 View FIGURES 257–262 , 274–290 View FIGURES 274–280 View FIGURES 281–285 View FIGURES 286–290 , 417–418 View FIGURES 411–422 )

Type genus: Strongylophthalmyia Heller 1902: 226 View in CoL [n. n. Strongylophthalmus Hendel , preoccupied by Motschoulsky, 1860], by Hendel 1917: 37 [incorrect original spelling (“Strongylophthalmyinae“), corrected to Strongylophthalmyiinae in Brues & Melander (1932: 340)]. Type species of genus: Chyliza ustulata Zetterstedt, 1847 , by automatic designation [type species for Strongylophthalmus ].

The family Strongylophthalmyiidae , or “hardwood flies”, is known from a single Vietnamese female of Nartshukia Shatalkin ( Shatalkin, 1993, 1994), and 87 species of Strongylophthalmyia ( Evenhuis, 2016; Galinskaya & Shatalkin, 2018), although there are certainly dozens more undescribed, with Evenhuis (2016) estimating approximately 150 species. Many Strongylophthalmyia are distributed in the eastern Palaearctic Region, but most occur in the Orient. Two species occur in the Nearctic and several species extend into, or are endemic to, the Australian Region including mainland Australia, but this Region’s fauna remains undescribed. The family is unknown from the Neotropics, Europe and Africa, with the two described Afrotropical species transferred to the family Clusiidae by Barraclough (2000). The family shows a relatively clean east/west division with its sister-family Tanypezidae , which is primarily New World in distribution ( Lonsdale, 2013).

Within Strongylophthalmyia, Shatalkin (1996) described two species groups that he recognized were not monophyletic and did not encompass most species in the genus. One group was defined by long, thin processes on the epandrium ( S. crinata group) and one was defined by a dorsal process on the male first flagellomere ( S. punctata group). Evenhuis (2016) placed almost all species in four provisionally accepted species groups (pending phylogenetic analysis): the S. punctata group (including the S. punctata and S. coarcta subgroups), the S. crinata group, the S. ustulata group and the S. fascipennis group.

The two Nearctic species were thoroughly revised by Barber (2006). The Old World species were treated in a series of small regional treatments in Frey (1955), Steyskal (1971a), Krivosheina (1981, 1999), Shatalkin (1981, 1993, 1996), Iwasa (1992, 1998), Iwasa & Evenhuis (2014), Yang & Wang (1992, 1996), Papp et al. (2006) and Galinskaya & Shatalkin (2016, 2018). Evenhuis (2016) has initiated a series of comprehensive reviews of the World Strongylophthalmyia , including a discussion of life history and a summary of historical study; a key to species groups and species is also included, but the importance of male-specific characters for diagnosis severely limits abilities to identify females. Regional catalogues include Shewell (1965) [Nearctic], Krivosheina (1984a), Palaczyk et al. (2013) [Palaearctic], Steyskal (1977d) [Oriental] and Evenhuis (1989c) [Australian]. A checklist of World spe- cies was provided by Iwasa & Evenhuis (2014), and a World catalogue is expected upon completion of the present series of revisions by Evenhuis (Evenhuis, pers. comm.).

Biology. Adults of Strongylophthalmyia are often found in forests on foliage, fallen tree trunks and stumps ( Shatalkin, 1994). Unidentified species have been observed in Australia on Alocasia foliage, and in New Guinea on banana foliage exhibiting ant-like behaviour ( Evenhuis, 1989c). Strongylophthalmyia crinata is also known to be drawn in large numbers to freshly cut stumps ( Shatalkin, 1994), and individuals have also been observed on “bleeds” in trees infected with pathogeneic fungi ( Barber, 2006) and near streams and waterfalls ( Papp et al., 2006).

Copulation may occur on dead wood, as observed for S. pengellyi ( Barber, 2006) , but it also occus on foliage, as seen in S. angustipennis ( Marshall, 2006; Evenhuis, 2016), S. crinata and S. raricornis (copulation described in detail in Shatalkin (1994)). Females have been observed ovipositing, or attempting to oviposit, on fallen trees and in holes bored in wood by beetles, possibly scolytids, with age, texture, and fungal associations of the dead wood possibly influencing site selection ( Barber, 2006; Palacztk et al., 2013; Evenhuis, 2016). Larvae of north temperate species have been reared from the inner layers of bark within rotting aspen, birch and elm, where mature or nearly mature larvae likely overwinter, with puparia recovered from the outer layers ( Krivosheina, 1981, 1984a; Barber, 2006). Nothing is known of the biology of Nartshukia .

Immature stages. The egg of S. angustipennis was photographed and described in Lonsdale (2013), and larvae were described in Barber (2006). The larva and puparium of S. ustulata were described by Mamaev et al. (1977) and Rotheray & Robertson (1998), respectively.

Adult Diagnosis. Relatively slender, gracile, somewhat ant-like. Head globose with broad concavity above foramen, not compressed as seen in Formicosepsis (Cypselosomatidae) . Antenna decumbent with first flagellomere slightly longer than wide (sometimes enlarged, bifid or with dorsal process), arista short pubescent to bare. Mostly brown to black with sometimes contrastingly pale setulae ( Figs 262 View FIGURES 257–262 , 274–280 View FIGURES 274–280 ). Ocellar seta well-developed, sometimes very long; postocellars divergent, often proclinate. Vibrissa absent. 2–3 small fronto-orbitals with anterior seta shorter. Usually 1 or 2 dorsocentrals, but sometimes up to 7. Usually 1 anepisternal (0 in Nartshukia ). 0 katepisternals. Lateral scutellar seta reduced to absent. Precoxal bridge large and well-developed ( Fig. 279 View FIGURES 274–280 ); postmetacoxal bridge absent. R 4+5 usually parallel to M 1, rarely converging. Costal break present; subcosta usually incomplete, sometimes faintly extending to costa.

Adult Definition. Generally ant-like in form, with small, slender body and narrow legs ( Figs 262 View FIGURES 257–262 , 274–280 View FIGURES 274–280 ). Colour black to brown, with pale setulae in some, and often with paler or yellow areas on head, thorax and legs; thorax sometimes with bluish iridescence; halter white with stem sometimes darker and knob sometimes dark. Body sometimes with conspicuous microtexturing on notum (similar to Cypselosomatidae ) and microstriations on frons; microtexturing sometimes also on clypeus, and less frequently on pleuron and abdomen. Body length 2.0– 7.5mm.

Chaetotaxy: Setae mostly fine and difficult to differentiate from long setulae. Setae mostly dark, setulae mostly yellowish and often long; setulae sometimes relatively dense but often reduced on head and thorax, sometimes excluding anepisternum and venter of katepisternum; body usually glabrous and smooth, sometimes with thin micropilosity. 1 inner vertical; 1 outer vertical; 2–3 fronto-orbitals (reclinate to slightly lateroclinate, anterior seta shorter); 1 ocellar (usually long, but sometimes shorter than postocellar); 1 postocellar (divergent, removed from ocelli, erect to proclinate in Strongylophthalmyia ); vibrissa absent; usually numerous genal setae extending dorsally along tomentose parafacial (absent in Nartshukia ). Scape with scattered marginal setae and one dominant dorsal seta; pedicel with dominant dorsal seta that may be elongate; first flagellomere often densely pilose. Frons with sparse row of lateral setulae and anterior margin with one to several pairs of minute to relatively well-developed setae; postgena covered with long pale pile; postocular setae mostly short and scattered, with dorsal setae (lateral only) in series. 0–1 presutural intra-alar; 0–1 postpronotal (weak if present); 1–2 notopleurals; 1–2 posterior supra-alar (sometimes reduced); 0 posterior intra-alars; usually 1 dorsocentral, sometimes 2–3, uncommonly 4 to 7 (anterior setae reduced with at least one presutural); 0 acrostichals (reduced pair uncommonly present); 1–2 scutellars (lateral pair weak if present); 0 or 1 ( Nartshukia ) proepisternal; 1 or 0 ( Nartshukia ) anepisternals; 0 katepisternals. One pair of small scapular setae anteriorly on scutum in S. splendida Yang & Wang ( Galinskaya & Shatalkin, 2016) . Halter stalk with series of pale setae. Male fore femur sometimes with dark stout setae dorsally, sometimes in two rows, but sometimes only 1 seta ventromedially; mid tibia with ventroapical seta; male femora sometimes with longer ventrobasal seta. Abdomen with longer setae laterally and posteriorly. Epandrium, surstylus and sternites 7 and 8 bare, with “pebbled” texture.

Head. Antenna decumbent; first flagellomere often discoid, slightly longer than wide (difference sometimes negligible), sometimes enlarged and ovate or unusually shaped (eg. bifid or with small to very large process resembling thickened arista); arista short pubescent to bare, length sometimes reduced to half length of first flagellomere. Head globose, slightly wider than thorax and slightly longer than high, with postgena and occiput bulging; back of head with medial concavity, excluding rounded shelf above foramen. Frons with minute, shallow striations; narrowing anteriorly and sometimes slightly projecting over antennal base; ocellar triangle narrow to relatively wide, usually indistinct, not attaining anterior margin. Ocelli removed from postocellar setae, usually situated near midpoint of frons ( Strongylophthalmyia ), but sometimes close to vertex ( Nartshukia ). Anteromedial ommatidia slightly enlarged. Parafacial and sometimes anterior margin of orbital plate slightly produced lateral to antennal base, with parafacial sometimes shallowly carinate; parafacial and gena with silvery tomentose band extending to posteromedial margin of eye. Gena very shallow, less than 1/10 height of eye. Face sclerotized dorsolaterally; with narrow medial membranous space widening to buccal cavity; face/parafacial sometimes reduced in height, and usually at least slightly compressed laterally due to convergence of eyes (more extreme cases similar in appearance to Megamerinidae , which may also have dense silvery pilosity on parafacial); shallow facial carina developed in Nartshukia . Male clypeus band-like, subquadrate, sometimes membranous and appearing absent; female clypeus thick, bulbous, sometimes very large and plate-like, projecting or deeply recessed; palpus subcylindrical; male palpus sometimes compressed, leaf-like, pediculate, clavate or with small process, sometimes with several scale-like setae; labium short, bulging laterally, with long setae.

Thorax. Relatively narrow with presutural regions slightly lengthened, removing fore coxa anteriorly. Transverse suture sometimes nearly complete. Notopleuron mostly sunken. Scutellum small, rounded or with sides and apex straighter. Greater ampulla absent. Coxopleural streak present. Katatergite narrow, sometimes bulging. Precoxal bridge present, broad; sutures between postpronotum, proepisternum (bulging) and prosternum indistinct ( Fig. 279 View FIGURES 274–280 ); postmetacoxal bridge absent.

Wing. Clear, clouded, with faded spot or band(s); wing interference patterns discussed in Evenhuis (2016). Alula small and anal lobe well-developed or slightly narrowed. Veins R 4+5 and M 1 convergent ( Nartshukia , S. curvinervis Frey ; Fig. 417 View FIGURES 411–422 ) or parallel to very slightly convergent (most Strongylophthalmyia ; Fig. 418 View FIGURES 411–422 ); M 1 often arched in Strongylophthalmyia , similar to some Psilidae . M 4 and CuA+CuP not reaching wing margin, but sometimes very closely approaching it. Vein CuA slightly bent ( Strongylophthalmyia ) or straight ( Nartshukia ). Costal break present; subcosta usually incomplete, sometimes faintly extending to costa. Calypter broadly lobate, hairs long.

Legs. Slender, fore legs up to half length of other legs. Male fore leg sometimes with secondary sexual charac-ters—fore tibiae and basitarsomeres bent, flattened or deviated, apparently for clasping purposes while mating (see Barber (2006)), setae sometimes pattered or thickened and clustered, sometimes with short spicules; mid basitarsus sometimes modified. Hind trochanter and/or femur base uncommonly with one or two inner-basal processes; hind basitarsus sometimes with scale-like setae (both sexes).

Abdomen. Slender, tapering ( Fig. 286 View FIGURES 286–290 ). Sternites less setose, partially desclerotized along midline to S 7 in females and S 5 in males. Spiracles 1–6 in membrane below tergite. 7 th spiracle absent. Membrane with relatively long, shaggy microtrichia. Pregenitalic sclerites subrectangular, mostly longer than wide with S1 broader and shorter; sternites smaller, less sclerotized to membranous.

Male genitalia. ( Figs 281–285 View FIGURES 281–285 ) S6 well-defined, ventral to left lateral, apically setose, well sclerotized along distal and left lateral margins, incorporated into elongate pregenital band mostly composed of large dorsal S8. Surstylus fused to epandrium, narrow when apparent, sometimes apically ribbon-like ( S. crinita group); inner-distal surface with short, stout setae. Epandrium sometimes basally constricted, sometimes with long, thin, sometimes branched ventral process. Subepandrial sclerite composed of one pair of flat, bare adjoining plates. Cerci narrow, sometimes elongate, fused along length (mostly via membrane). Hypandrium arched with narrow ventromedial bridge and single ventral seta on each lobe; with ventromedial process that is sometimes apically bifid (interpreted as postgonite by Barber (2006)). Phallapodeme long, rod-like, with one pair of processes that widen to point of fusion with hypandrium. Pregonite very long, narrow and band-like, with apex slightly swollen and setose; base fused to inner surface of hypandrium. Postgonite absent. Phallic plate divided into two articulating sclerites. Epiphallus absent. Distiphallus narrow and extremely long (“globular” in S. thaii Papp ( Papp et al., 2006)) , with sclerotized bands and apical “glans”, usually unsegmented, membrane minutely trichose. Ejaculatory apodeme sometimes small, narrow to finger-like with subbasal swelling.

Female genitalia. ( Figs 286–290 View FIGURES 286–290 ) Segment 6 broad medially, tapered at base; margins of T6 and S6 sometimes meeting but not fused. T7 and S7 completely fused on basal ¾ to form slightly narrowing sclerotized tube, with lateral and dorsomedial emarginations, and with linear ventromedial weakening or sulcus; distal ¼ of segment essentially membranous with ring of marginal setae. Segments 7 and 8 separated by extremely long intersegmental space. T8 and S8 medially divided into two pairs of sclerotized bands; line of setae on ventral bands. S10 and T10 relatively elongate and well-developed, with long, narrow internal process emerging as apodeme from S10. Cerci moderately long, curved in cross section, fused along most of length via membrane. Segments 7–10 mostly retractile, forming slender ovipositor. Genital chamber with folded vaginal sclerite. Ventral receptacle transverse, reniform, with surface corrugated to lobate. 2 spermathecae, one atrophied or absent, the other short, broad and telescoped, with minute transverse wrinkles; ducts fused near base.