Pseudopomyzidae McAlpine, 1966

Lonsdale, Owen, 2020, Family groups of Diopsoidea and Nerioidea (Diptera: Schizophora) - Definition, history and relationships, Zootaxa 4735 (1), pp. 1-177 : 48-50

Pseudopomyzidae McAlpine, 1966

( Figs 233–256 , 415–416 )

Type genus: Pseudopomyza Strobl 1893: 284 , by McAlpine, 1966: 683. Type species of genus: Pseudopomyza nitidissima Strobl, 1893: 284 [= Opomyza atrimana Meigen, 1830: 106 ], by monotypy.

The Pseudopomyzidae incudes the following extant taxa: Heloclusia Malloch ( Chile; 1 species; Figs 233–236 ), Latheticomyia Wheeler (Nearctic and Neotropical; 7 species, with at least two more undescribed in Central America ( Buck & McAlpine, 2010; Marques & Rafael, 2016); Figs 238–241 ), Polypathomyia Krivosheina (eastern Palaearctic; 1 species), Pseudopomyzella Hennig (Neotropical; 1 species), Pseudopomyza Strobl (all regions except Afrotropics; 11 species, with at least several more undescribed in the Neotropical Region ( Buck & McAlpine, 2010) and Thailand ( Merz, 2006); Fig. 242–243 ), Tenuia Malloch (Palaearctic and Oriental; 2 species). One fossil genus is known from Baltic amber that includes two species: Eopseudopomyza kuehni Hennig and E. szadziewskii Hoffeins & Woźnica ; specimens identified as “ Pseudopomyzidae sp.” are listed in Tschirnhaus & Hoffeins (2009).

Keys to World genera were provided in the family treatments of Hennig (1969) and Krivosheina (1979). The New World and Palaearctic genera are keyed and discussed in Buck & McAlpine (2010), and McAlpine & Shatalkin (1998), respectively. Pseudopomyza and its constituent subgenera were treated in McAlpine (1994), who recognized Pseudopomyza , Rhinopomyzella, and the new subgenera Apops McAlpine and Dete McAlpine ; Macalpinella Papp was also included as a subgenus by Buck & McAlpine (2010). McAlpine (1996) redefined the family and proposed three tentative genus groups: “Group 1” ( Latheticomyia , Tenuia ), “Group 2” ( Heloclusia , Polypathomyia , Pseudopomyza ) and “Group 3” ( Pseudopomyzella and Eopseudopomyza ).

The species of Pseudopomyzidae were catalogued regionally in Krivosheina (1984b) [Palaearctic], Vockeroth (1977) [Oriental], Mathis (1989b) [Australian] and Prado (1984) [Neotropical, as part of Cypselosomatidae ]. Wheel- er (1956) and Marques & Rafael (2016) provide keys to the species of Latheticomyia ; New World Pseudopomyza are keyed by Hennig (1969) and New Zealand species by Harrison (1976). The two fossil species of Eopseudopomyza are keyed by Hoffeins & Woźnica (2013).

Biology. Species are generally considered to be uncommon or rare, having “potentially narrow ecological requirements” ( McAlpine & Shatalkin, 1998), but Pseudopomyza (see below) and Rhinopomyzella can sometimes be abundant.Adults have been found in forests, and similar to many Cypselosomatidae , may occur at higher elevations ( McAlpine & Shatalkin, 1998). Frey (1952) observed adult Pseudopomyza atrimana swarming over recently fallen logs and Roháček (2012a) found this species en masse on heaps of rotting grass cuttings where mating was observed to take place. Roháček (2012a, b) also thoroughly summarized habitat associations for this species in the literature, including other occurrences of adults on fallen wood and rotting substrates, as well as on flowers and recently cut stumps or logs of deciduous trees, and he noted the spring emergence of adults that may have developed on rotting vegetation. Larvae of Polypathomyia stackelbergi Krivosheina have been found under bark (including roots) of rotting deciduous trees such as Maackia , Phellodendron , Kalopanax and oak ( Krivosheina, 1979, 1984b; McAlpine & Shatalkin, 1998). Tenuia is known from localities with osier and has been seen on willow sap (see McAlpine & Shatalkin (1998)). Neotropical species are attracted to decaying vegetation, particularly fallen trees, and have been observed around kitchen compost. Some Latheticomyia , particularly the males, are also attracted to dung baits, especially when the bait is positioned near logs or moss near streams (Marshall, in Buck & McAlpine, 2010), and Latheticomyia have been recovered from banana-baited Drosophila traps ( Wheeler, 1956). In New Zealand, Pseudopomyza brevis (Harrison) was found under plant litter and dead sea birds, and P. brevicaudata (Harrison) was found in a fowl yard ( Harrison, 1976). Large numbers of Polypathomyia stackelbergi are known to swarm around small vertebrate carcasses ( McAlpine & Shatalkin, 1998).

Immature stages. No immature stages have been described.

Adult Diagnosis. Small to medium sized flies, 1.5–5.5mm long, colour mostly brown, sometimes similar in appearance to some Cypselosomatidae and Sphaeroceridae (particularly Limosininae and Copromyzinae , which also lack an anepisternal seta) ( Figs 233–236 ); Latheticomyia ( Figs 238–241 ) is reminiscent of small pruinose Neriidae . Postocellars convergent, distant from ocellar tubercle; usually 3 fronto-orbitals (reclinate to lateroclinate); usually one pair of paraverticals; vibrissae present. At least 4 dorsocentrals; usually 1–4 pairs of transverse “scapular” setae near anterior margin of scutum; sometimes with paired prescutellar acrostichals, sometimes with single medial series of sutural acrostichals ( Pseudopomyza ); anepisternals usually absent; 1–2 katepisternals, uncommonly 0. Wing with subcostal break and also humeral break or weakening ( Figs 415–416 ). Femora with slender ventrobasal seta (sometimes absent from hind leg); fore femur with several long posteroventral setae (posteriorly directed) and with posterodorsal row of similar long setae; hind femur with large anterodorsal seta past midpoint.

Adult Definition. Relatively small-bodied and compact. Body length 1.5–5.5mm. Colour mostly brown with yellow to white regions, mostly on head and legs, but sometimes with dark pattern on head or mostly yellow ( Figs 233–236 ); Latheticomyia with broad white to yellowish stripes ( Figs 238–241 ). Mesonotum and frons (excluding orbital plate) usually pruinose to matte, but sometimes glossy; pleuron lightly pruinose to glossy.

Chaetotaxy: 1 inner vertical; 1 outer vertical; usually 3 fronto-orbitals (reclinate to lateroclinate, anterior pair sometimes reduced; only two pairs in some Pseudopomyza , 4 in Pseudopomyzella ); 1 ocellar (long); 1 postocellar (convergent); dorsomedial seta(e) behind ocellar tubercle usually enlarged as paraverticals; vibrissa present ( Fig. 242 ). Pedicel with at least one marginal row of setae, including one large dorsal and sometimes several large ventrals. Frons with scattered setulae. Face bare or dorsally setulose (sometimes only indistinctly so in Pseudopomyza and Heloclusia ). Postoccipital setae usually in distinct row, at least dorsally; sometimes additional smaller and/or scattered setae laterally. Gena with setulae usually minute, linear to scattered, but sometimes with one outstanding medial seta that may appear as duplicated vibrissa. 2–3 subgenal setae with anterior seta sometimes positioned anteriorly on gena. Labium with 1 strong medial and 1–2 strong distal setae. 1 presutural intra-alar (absent in some Pseudopomyza ); 1 postpronotal; 2 notopleurals; 2 posterior supra-alars; 2 posterior intra-alars (smaller seta at posterior margin sometimes setula-like); 4–5 dorsocentrals (at least one presutural); acrostichals sometimes absent ( Latheticomyia , Polypathomyia , Heloclusia ), sometimes present as one or two prescutellar pairs, and Pseudopomyza with single medial sutural to presutural row of one to several setae ( Fig. 243 ); 2–5 scutellars (decreasing in length anteriorly, rarely all short; apical scutellar seta uncommonly on minute tubercle ( Pseudopomyzella )); 1 proepisternal (sometimes on shallow tubercle); anepisternum usually bare, rarely setulose with outstanding seta ( Pseudopomyzella ); 1–2 katepisternals, uncommonly 0 (some Pseudopomyza ). 1–4 pairs of transverse scapular setae across anterior margin of scutum (absent or with one reduced pair in some Pseudopomyza ). Scutellum sometimes setulose dorsally and marginally. Prosternum bare. Femora with slender ventrobasal seta that is sometimes absent from hind leg; fore femur with several long posteroventral setae (posteriorly directed), and with posterodorsal row of similar long setae; hind femur with large anterodorsal seta past midpoint (sometimes reduced, eg. Latheticomyia ). Mid tibia with ventroapical seta, and fore or hind tibia sometimes with similar seta. Heloclusia relatively hirsute, with legs and venter of pleuron long setulose, and with stout setae on femora and tibiae. Fore basitarsus with longer ventrobasal setae.

Head. Antenna porrect; first flagellomere discoid or slightly truncated to shallowly pointed; arista short pubescent, sometimes elongate, inserted on first flagellomere apically to subapically. Frons flat to sunken medially, sometimes convex; ocelli shifted anteriorly, leaving narrow gap between tubercle and postocellar. Face partially membranous, at least ventromedially, distinct from surrounding sclerotized regions; sometimes with variably developed facial carina or bulge below antennal bases. Gena shining and bulging, ususally at least 1/3 height of eye to almost one-half height, but sometimes as shallow as 1/9 height (eg. some Latheticomyia ). Clypeus narrow to relatively thick, U-shaped with anterior margin sometimes slightly truncated; palpus subcylindrical to slightly compressed or spatulate.

Thorax. Precoxal and postmetacoxal bridges absent. Prosternum very narrow, linear. Greater ampulla shallow. Coxopleural streak usually weak to absent. Dorsal katepisternal suture meeting complete proepimeral suture at right angle or near right angle.

Wing. ( Figs 415–416 ) Clear to infuscated. Costa with sc break; also with humeral weakening (eg. Latheticomyia ) that usually produces a break (eg. Pseudopomyza ); costal margin sometimes spinulose ( Tenuia , Heloclusia , Polypathomyia ); vein sc complete or ending freely in subcostal cell very close to terminus of vein R 1. Veins R 4+5 and M 1 subparallel. M 4 usually not reaching wing margin; CuA+CuP not reaching wing margin. Vein bm-m usually absent, but sometimes partially developed or complete. CuA sometimes atrophied to absent. Pseudopomyza brevis brachypterous.

Legs. Legs slender, relatively short. Fore basitarsomere with anteroventral process in Polypathomyia ; some male Latheticomyia with similar lobate process on inner surface.

Abdomen. Sternites shorter or longer than wide, often bare medially, sometimes desclerotized along midline. Spiracles 1–6 sometimes in membrane, sometimes associated with tergal margin or enclosed; 7 th spiracles usually enclosed by sclerites.

Male genitalia. ( Figs 244–249 ) Terminalia essentially symmetrical, but sometimes with phallus strikingly asymmetrical (eg. Fig. 248 ). S6 separate, symmetrical, variably modified (eg. overlapping S7 and S 8 in Pseudopomyza , or produced as forked process in Tenuia ). S7 and S8 forming complete or nearly complete sclerotized ring, with S8 large mostly dorsal and dome-like, often with one pair of large, stout dorsal setae; slightly asymmetrical. Subepandrial sclerite flat, U-shaped with apical setae. Epandrium relatively narrow with slight basal constriction and usually with one pair of dominant posterodorsal setae; dominant setae sometimes absent from S8, or both S8 and epandrium. Cerci narrow, connected along length via membrane, but Tenuia and Polypathomyia with apices broad and fused. Surstylus narrow, sometimes bent, curled or clavate; sometimes with small spine-like setae apically. Hypandrium with arms joined dorsally, fused to phallic plate that reaches basiphallus. Phallapodeme separate from hypandrium, rod-like. Pregonite long, band-like, with minute setae (reduced in Tenuia ); end of pregonite reaching band-like postgonite that is swollen and setose apically. Epiphallus absent. Basiphallus separate from distiphallus, often cylindrical, sometimes elongate. Distiphallus often elongate and rod-like along most of length, sometimes curved; phallus short, sometimes asymmetrical. Ejaculatory apodeme well-developed to small, widening apically.

Female genitalia. ( Figs 250–256 ) T7 and S7 fused into stout oviscape with suture at least partially evident; widest subbasally, strongly narrowing apically; sometimes with paired ventrobasal bulges; spiracles sublateral, sometimes within membranous fissure reaching intersegmental membrane. T8 and S8 divided, roughly textured with tooth-like denticles that are also found along intersegmental membrane to segment 10. T10 with two apical setae; S10 with four apical setae and numerous sockets extending along short, narrow internal process with apical disc. Cercus short, rounded, approximate, minutely setose. Ventral receptacle with stalk and apical bulb. Two sper- mathecae, sometimes asymmetrical; on relatively short membranous duct.

Figures

FIGURES 233–243. Figs 233–237: Heloclusia imperfecta Malloch (Pseudopomyzidae); 233: female dorsal; 234: same, lateral; 235: head anterior; 236: head dorsal; 237: male, Chile. Figs 238–241: Latheticomyia sp. (Pseudopomyzidae), male; 238: head, anterior; 239: head, dorsal; 240: dorsal; 241: lateral. Fig. 242: Pseudopomyza atrimana (Meigen) (Pseudopomyzidae), head anterior. Fig. 243: Pseudopomyza (Rhinopomyzella) sp., dorsal.

FIGURES 244–249. Pseudopomyza atrimana (Meigen) (Pseudopomyzidae), male terminalia; 244: lateral; 245: external genitalia, posterior; 246: same, anterior; 247: sternites 6–8, ventral; 248: internal genitalia, ventral; 249: same, left lateral.

FIGURES 250–256. Figs 250–251: Latheticomyia sp. (Pseudopomyzidae), female abdomen; 250: ventral; 251: lateral. Figs 252–256: Pseudopomyza atrimana (Meigen) (Pseudopomyzidae), female abdomen; 252: segments 4 to cerci (terminalia retracted), ventral; 253: segment 7, lateral; 254: segment 10 and cerci, ventral; 255: same, dorsal; 256: 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).