Neriidae Westwood, 1840

Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, Zootaxa 4735 (1), pp. 1-177 : 45-48

Neriidae Westwood, 1840

( Figs 291–311 , 412 )

Type genus: Nerius Fabricius 1805: 264 , by Westwood (1840: 588). Type species of genus: Nerius pilifer Fabricius, 1805 , by subsequent designation [ Coquillett 1910: 575].

The Neriidae is a relatively small family of almost global distribution with over 110 species in more than 19 genera ( Sepúlveda et al., 2013a) that are primarily tropical in distribution, with most species found in the Neotropical Region. Species often develop as immatures in decaying vegetable matter, including a Nearctic Odontoloxozus that is found in necrotic cactus tissue, giving rise to the common name “cactus flies”.

The widespread subfamily Neriinae is defined by prominent antennal bases formed by an enlarged and medially divided lunule. The Old World subfamily Telostylinae is characterized by an ancestral form of antennal insertion, leading some to suspect that it represents a paraphylic group from which the Neriinae arose ( Pitkin, 1989; Buck, 2010). A closer, quantitative analysis of the phylogenetic relationships between neriid genera was performed by Koch et al. (2014), who used a combination of discrete and continuous morphological characters to dismantle support for all historically defining characters of the subfamilies and genus groups, finding these to support artificial groupings; the family itself was strongly supported as monophyletic and the previous assumption of an Oriental origin for the family ( Aczél, 1954b) was supported. Since Koch et al. (2014) did not provide an alternative system of classification and their phylogeny does not support any simple subdivision of the family, it is not recommended that any be imposed until a more extensive analysis of global taxa is performed, followed by correlation of useful diagnostic characters to natural groups. The doctoral thesis of Pereira-Colavite (2013) is a preliminary step in this direction, but this requires publication and verification. The monophyly of genera should also ideally be examined following revision, as recently done for Glyphidops Enderlein ( Sepúlveda et al., 2014) and the smaller genera Cerantichir Enderlein ( Sepúlveda et al., 2013a) , Eoneria Aczél ( Sepúlveda et al., 2013b) and Longina Wiedemann ( Buck & Marshall, 2004) , which are now much more thoroughly understood.

The New World fauna was revised by Aczél (1961) and discussed in Buck (2010). The much smaller Palaearctic fauna was treated in Czerny (1930b, 1932) and Hendel (1932). Aczél (1954b, 1955a, 1959) treated portions of the fauna of Southeast Asia and Oceania. Afrotropical species are treated in Aczél (1954c, 1954d, 1955b) and Barraclough (1993a, b). The only thorough investigation of the World Neriidae was provided by Hennig (1937), who wrote a key to genera and reapproached the classification and zoogeography of the family. Species limits in two Nearctic Odontoloxozus established using molecular data are discussed in Pfeiler et al. (2013). Telostylinus angusticollis is used as a model organism in experimental biology, as summarized in Kopps et al. (2013), who provided genetic sequence data and developed microsatellite markers. Regional species catalogues are provided in Steyskal (1965c) [Nearctic], Czerny (1930b), Soós (1984b) [Palaearctic], Steyskal (1977b) [Oriental], Pitkin (1989) [Aus- tralian], Steyskal (1980a) [Afrotropical], and Aczél (1949c), Steyskal (1968b) and Sepúlveda & Carvalho (2016) [Neotropical].

Biology. Larvae are known to breed in decaying vegetable matter, often fruit, but specimens are sometimes found in rotting tree bark (including Carica and Dysoxylum ), wood that has only recently begun to decay ( Eberhard, 1998), stems (Oosterbrook, 1989; Pitkin, 1989) and beetle borings from wood ( Preston-Mafham, 2001). Other species occur in injured or diseased tree tissue (Buck, 2010), including the New World Odontoloxozus , which occurs on necrotic cactus ( Ryckman & Olsen, 1963). Larval breeding spots interpreted as favourable oviposition sites by females of some species are guarded by males, with some males also guarding females following copulation and during oviposition ( Mangan, 1979; Preston-Mafham, 2001). Adults feed on sap, the excretions of rotten trees, fruit, and other decaying matter including carrion and dung (Buck, 2010; Dufek et al., 2014), and can be collected in fruit-fly traps ( Aczél, 1961). Telostylinus lineolatus (Wiedemann) was considered an opportunistic feeder on a decomposing pig carcass ( Chin et al., 2011). Immature stages of O. longicornis were described by Olsen & Ryckman (1963) and Steyskal (1965), and immature stages and the development of larvae of Glyphidops flavifrons (Bigot) were described by Mondragón & Cironza (2016).

Immature stages. Immature stages of Neriidae are best known for Odontoloxozus longicornis , with Olsen & Ryckman (1963) detailing the egg, larvae and puparium, the first of which has a characteristic elongate anterior filament that projects through the host epidermis ( Olsen & Ryckman, 1963: figs 1, 19). Berg (1947) further detailed the third instar larva and puparium of Telostylinus lineolatus . Managan & Baldwin (1986) examined the larvae of O. pachycericola Managan & Baldwin , O. longicornis , and their hybrids, from which polytene chromosomes were extracted and analyzed.

Adult Diagnosis. Body length 5.0–15.0mm. Body long and slender, accentuated by lengthened head, anteriorly pointed and often elongate antenna with apical arista, and straight, horizontally held abdomen; more heavily sclerotized and spinose than similar families such as Micropezidae . Legs long and slender, sometimes stout; femora usually originating relatively close to each other under midpoint of body. Usually conspicuously vittate and sometimes with glabrous spots at base of setae. Setae and setulae reduced, with remaining setae often dark, short, erect and sometimes stout to spinose; thickened setae usually present at least on fore femur or coxa, but sometimes also on remaining coxae and femora, pleuron and subgena. Ocellars absent; postocellars convergent and distant from anteriorly removed ocellar tubercle. Vibrissa-like seta often small if present. Thoracic chaetotaxy reduced, but with at least 1 dorsocentral, 1 posterior notopleural and 1 apical scutellar. Face mostly to entirely membranous; projecting, not distinct from lunule. “Antennal base” sometimes appearing as additional antennal segment. Pedicel with angulate extension on inner-distal margin ( Fig. 294 ). Precoxal bridge sometimes present. Subcostal break or weakening usually absent; subcosta complete ( Fig. 412 ). Veins R 4+5 and M 1 convergent. Female with segment 7 forming large ovipositor that encloses terminal segments at rest ( Figs 306–307 ); male with epandrium long, narrow and usually constricted medially ( Figs 299–302 ).

Adult Definition. Body long and slender, with form accentuated by often elongate head and antenna, apical arista, and abdomen that is held straight and horizontally; body appearing more heavily sclerotized and spinose than similar families such as Micropezidae . Colour usually brown to yellow or reddish; often conspicuously vittate, particularly on head, notum, pleuron and abdomen; sometimes with spots at base of setae; halter white with knob and parts of base sometimes brown; arista often white. Usually microtomentose with legs, ovipositor and portions of head shining to subshining, sometimes in addition to pattern of glabrous spots on thorax and abdomen; face, lunule and frons (at least around tubercle) velvety; parafacial often silvery. Body length 5.0–15.0mm.

Chaetotaxy: 1 inner vertical (sometimes indistinct); 0–1 outer vertical (sometimes small and indistinct); 1–5 fronto-orbitals (erect); 0 ocellars; 1 postocellar (convergent, sometimes subparallel when short, not moved anteriorly with ocelli, leaving intervening gap); sometimes small vibrissa-like seta present on genal margin near posterior margin of eye. 1–0 dark, stout subgenal setae, but gena, subgena and occiput also with scattered dark and/or pale, fine setae, particularly at posteroventral angle, where it may be dense. Back of head with one pair of discrete setulose patches above foramen (also some Pseudopomyzidae ). Postoccipital setae weak, scattered, sometimes with 1 to several dark outstanding setae dorsally or laterally. 0 presutural intra-alars; 0–1 postpronotal; 1–2 notopleurals (anterior seta reduced to absent); 2 posterior supra-alars; 0 posterior intra-alars; 1, 2, 5 or 6 dorsocentrals; 0 acrostichals; 1–2 scutellars (lateral seta often reduced if present and positioned dorsally); 0–1 proepisternal (sometimes fine and inconspicuous if present, and usually on shallow to conspicuous ridge); 0 anepisternals; 0–1 katepisternal. Setae usually short and stout, setulae usually reduced to absent; at least some setae on fore femur or fore coxa spinose or thickened; spinose setae sometimes also present on remaining coxae and femora, pleuron and subgena; females with fewer spinose setae that are mostly or only present on legs. Femora sometimes with two ventral rows of spinose setae, sometimes on tubercles, becoming less distinct basally and/or with posterior row reduced; femora sometimes with several thicker dorsal setae. Legs with straight rows of setulae that are often along ridges (pronounced on tibiae); fore tibia with one dorsoapical and sometimes one ventroapical seta; mid and hind tibiae with at least one outstanding ventroapical seta, and often with small or moderately developed dorsoapical seta. Pregenitalic sternites with reduced setation, particularly along midline.

Head. Antenna porrect, sometimes laterally compressed, usually elongate and narrow; scape sometimes with transverse dorsomedial groove; pedicel with pronounced extension on inner-distal margin; first flagellomere longer than wide, infrequently as enlarged as pedicel or scape, apex usually pointed but sometimes rounded, truncated or angulate; arista apical to dorsoapical with hairs pubescent to absent. Antenna sometimes separated from frontal vitta by “antennal bases” ( Fig. 293 ) that possibly originate from lunule; “antennal bases” are small to large and bulbous, are separate or confluent dorsomedially, and may smoothly meet parafacial laterally or be divided from it by suture. Face membranous, sometimes with dorsolateral margin sclerotized; face and parafacial elongate, projecting. Frontal vitta sunken medially; anterior margin straight to pointed. Orbital plate sometimes with short, truncated apodeme projecting internally ( Fig 296 ) (only verified for Gymnonerius fuscus Wiedemann and Telostylinus sp.). Occiput and postgena elongate and distinct when viewed laterally, with occiput never exceeding length of eye; if back of head produced and bulging, then anterior margin of thorax similarly bulging to form truncated abutment. Mouthparts often long and narrow; palpus narrow, flat/compressed; labium with distal processes well-developed, usually with one pair of stout basomedial setae and one pair of finer apical setae.

Thorax. Often elongate due to lengthening of presutural thorax; proepisternum relatively large. Transverse suture sometimes complete. Scutellum with dorsum slightly convex to flat, sometimes grooved. Anterior spiracle often above sunken recess encompassing discrete bulge. Katatergite bulging. Prosternum usually narrow and linear, sometimes wide and plate-like, sometimes partially bilobed anterior to coxae; some taxa (including Nerius and Loxozus ) with especially broad prosternum reaching (and sometimes fused to) incurved proepisternum, forming precoxal bridge. Postmetacoxal bridge absent.

Wing. ( Fig. 412 ) Usually clear to slightly clouded, or with more discrete clouding either apically, anteriorly, or along veins; often with general yellow to brown tint that becomes darker anterodistally. Sometimes dm-m or radial and medial veins shallowly sinuate. CuA+CuP not reaching wing margin; M 4 reaching wing margin. Vein bm-m sometimes weak or atrophied. Radial and medial veins, and dm-m, sometimes with supernumerary veins. Alula and anal lobe well-developed, but wing sometimes relatively slender. Subcostal break or weakening usually absent; subcosta complete. Calypter broadly lobate with hairs long.

Legs. Long and slender, with fore coxa and sometimes also femora and tibiae thickened. All femora usually originating relatively close together under midpoint of body. Tarsus sometimes longer than tibia.

Abdomen. Held straight and parallel to ground; sometimes relatively short. Pregenitalic sternites narrow with S1 transverse, narrow ( Fig. 306 ). Spiracles 1–6 in membrane; female 7 th spiracles ventromedial in small membranous pocket in oviscape (fused T7 and S7); both male 7 th spiracles absent. Terminalia relatively uniform across species.

Male genitalia. ( Figs 298–305 ) S6 short, symmetrical. S7 fused to downturned S8 left laterally. One pair of supernumerary sclerites in membrane anteroventral to S7+8. Subepandrial sclerite deeply divided, weakly sclero- tized medially; setose distolaterally. Epandrium elongate and narrow, almost always constricted medially. Cerci narrow, lobate, united along much of length by membrane. Surstylus small, finger-like. Internal genitalia, excluding basiphallus and postgonite, elongate and narrow. Hypandrium divided ventrally, inner-ventral surface fused to long, band-like pregonite; hypandrial arms meeting dorsally, fused to long, narrow phallic plate. Postgonite short, bandlike, apically swollen and setose. Phallapodeme separate from hypandrium, base flat. Epiphallus absent. Basiphallus small, fused to distiphallus. Distiphallus long, narrow, tubular and mostly membranous with one pair of parallel ventral ribbons; often with elongate membranous flagellum (removed in figure). Ejaculatory apodeme with stem stout, blade weakly sclerotized; sperm pump membranous.

Female genitalia. ( Figs 306–311 ) T7 and S7 fused into oviscape; elongate, widest subbasally and narrowing apically, slightly compressed dorsoventrally. T8 and S8 divided medially, minutely textured and band-like. Segment 10 small; 2 apical setae on T10, 4 apical setae on S10; S10 with internal apodeme that has small sockets along length and apical swelling. Cerci relatively short, rounded, approximate and minutely setose. 1+2 or 2+2 spermathecae ( Buck & Marshall, 2004), clear, with wide ducts. Ventral receptacle small, sac-like, sometimes indiscrete.

Figures

FIGURES 291–297. Figs 291–294: Odontoloxozus peruanus Hennig (Neriidae), male; 291: dorsal; 292: lateral; 293: head, dorsal; 294: head, anterior. Fig. 295: cf. Chaetonerius sp. (Neriidae), Seram, Indonesia. Figs 296–297: Telostylinus sp. (Neriidae); 296: lateral (note process arising from inner surface of orbital plate); 297: posterior.

FIGURES 298–305. Odontoloxozus longicornis (Coquillett) (Neriidae), male abdomen; 298: sternites 4–6, ventral; 299: external genitalia, anterior; 300: same, posterior (with detail of texture); 301: sternites 7–8, anterior; 302: terminalia, lateral; 303: internal genitalia, ventral; 304: same, left lateral; 305: ejaculatory apodeme.

FIGURES 306–311. Figs 306–310: Telostylinus sp. (Neriidae), female abdomen; 306: ventral (terminalia retracted); 307: segment 7 to cerci ((terminalia retracted), lateral; 308: segment 10 and cerci, lateral; 309: same, ventral; 310: same, dorsal. Fig. 311: Odontoloxozus longicornis (Coquillett) (Neriidae), female internal genitalia.

FIGURES 411–422. Wings: 411: Fergusonina sp. (Fergusoninidae); 412: Odontoloxozus longicornis (Coquillett) (Neriidae); 413: Clisa australis (McAlpine) (Cypselosomatidae); 414: Formicosepsis sp. (Cypselosomatidae); 415: Pseudopomyza (Rhinopomyzella) nigrimana Hennig (Pseudopomyzidae); 416: Latheticomyia sp. (Pseudopomyzidae); 417: Nartshukia musiva Shatalkin, holotype (Strongylophthalmyiidae); 418: Strongylophthalmyia angustipennis Melander (Strongylophthalmyiidae); 419: Tanypeza longimana Fallén (Tanypezidae); 420: Neotanypeza marshalli Lonsdale (Tanypezidae); 421: Compsobata mima (Hennig) (Micropezidae); 422: Micropeza sp. (Micropezidae).