Fungomyza buccata Roháček & Barber, 2004

Roháćek, Jindřich & Barber, Kevin N., 2016, Nearctic Anthomyzidae: a monograph of Anthomyza and allied genera (Diptera), Acta Entomologica Musei Nationalis Pragae (suppl.) 56, pp. 1-412 : 33-40

Fungomyza buccata Roháček & Barber, 2004

( Figs 33–46 )

Fungomyza buccata Roháček & Barber, 2004: 135 ; ROHÁĆEK (2009a): 88 (key), 110–111 (phylogeny).

Type material. HOLOTYPE: ♂, “ Stone Mt. , DeKalb Co., Ga. XI-II-1953, Dodge”, “ ♂ ”, “ HOLOTYPUS ♂ Fungomyza buccata sp. n., J. Roháček & K. N. Barber det. 2004” (red), deposited in USNM (intact) . PARATYPES: 5 ♂♂ 6 ♀♀ ( DEBU, LEMQ, SMOC, USNM) (details in ROHÁĆEK & BARBER 2004).

Other material examined (not included in type series). 1 spec. ( USNM, only wing preserved, see ROHÁĆEK & BARBER 2004).

Additional records. UNITED STATES OF AMERICA: ALABAMA: Baldwin Co., Silverhill, 30.53°N 87.74°W, (Site 9), Malaise trap, 15.xii.2004, 3 ♀♀, E. Benton leg. ( DEBU, O. Lonsdale det., K. N. Barber rev.).

Redescription. Male. Total body length 2.22–2.94 mm; general colour blackish brown, relatively shiny despite sparse greyish microtomentum, only extremities and head partly yellow or ochreous ( Fig. 33 ). Head distinctly higher than long ( Fig. 35 ); dorsal part of occiput slightly concave. Frons moderately broad, blackish brown posteriorly but becoming gradually paler anteriorly, orange ochreous in anterior third (lightest medially behind lunule), microtomentose and dull except for basal scars of ors and spots lateral to ocellar triangle. Orbits whitish microtomentose. Frontal triangle short, at most reaching half of frons. Frontal lunule orange, well developed. Occiput entirely blackish brown, shiny despite sparse greyish microtomentum, best developed in 2 bands behind ocellar triangle. Face (preafrons), parafacialia and gena whitish yellow to dark yellow, white microtomentose except for narrow and darker (pale brown) margin bordering parafacialia and gena; postgena orange ochreous ventrally, brown dorsally; mouthparts dark yellow. Cephalic chaetotaxy: pvt unusually long, strongly convergent or crossed; vte, vti and oc longest of cephalic setae, subequal or vte sometimes slightly longer than vti; 3 strong but relatively short ors, becoming shorter anteriorly, and 1 inclinate orbital microsetula in front of the foremost ors; 3–4 medial pairs of proclinate microsetulae in anterior half of frons; postocular setulae well developed but not longer than peristomals, in a single row; postgena with 1 longer ventral seta (as usual) and several shorter setulae; vi rather short (as long as anterior ors); subvibrissa reduced, unrecognizable from peristomal setulae that are all directed anterolaterally. Eye broadly suboval with longest diameter very slightly oblique and 1.2–1.3 times as long as shortest. Gena unusually high, with smallest height 0.20–0.23 times as long as shortest eye diameter. Palpus slender but clavate, with several black setulae ventrally, the subapical of which is distinctly longer. Antenna geniculate, orange, only 1st nagellomere brown in anterior half and shortly ciliate on anterior margin. Arista brown, about 1.7 times as long as antenna, very shortly ciliate.

Thorax slightly narrower than head, dark to blackish brown, relatively shining despite sparse grey microtomentum; humeral and notopleural areas duller, with denser microtomentum; scutellum microtomentose on margins but bare and more shining on disc. Thoracic chaetotaxy: 1 minute but distinct ppl; 1 hu, 2 npl (anterior longer); 1 sa and 1 pa (longer) strong but not long; 1 prs, well developed, as long as hu or longer; 2 dc (both postsutural), anterior strong but markedly shorter than the very long posterior dc; a number (more than 5) of dc microsetae in front of anterior dc; ac microsetae nne, in 4 rows at suture, in 2 behind anterior dc, not reaching behind posterior dc; 2 sc, laterobasal as long as or slightly shorter than anterior dc, apical as long as posterior dc; 2 stpl (anterior markedly shorter) and 1 microseta in front of anterior stpl; 1–2 other microsetae in dorsal half of sternopleuron but more and longer setae ventrally. Scutellum relatively long, rounded triangular, with convex disc.

Legs variegated, yellow and brown. Coxae ochreous yellow, trochanters paler. f 1 brown with yellow base and apex; t 1 dark brown except for yellow knee; fore tarsus with pale brown basitarsus, 2nd and 3rd segment yellowish ochreous, two apical segments brown. f 2 and f 3 pale ochreous basally and gradually darkened towards distal end but knee yellow; t 2 and t 3 brown but usually lighter than t 1 and with both ends yellow; mid and hind tarsi yellow, with 2 terminal segments brown (or apical segment dark brown). f 1 with ctenidial spine shorter than maximum width of t 1 and with posterodorsal and posteroventral setae thin and relatively short. t 2 with usual ventroapical seta. f 2 simply setulose. f 3 with posteroventral row of setae, 8–10 in apical two-thirds shortened and thickened. t 3 and hind basitarsus simply, nnely setulose.

Wing ( Fig. 34 ) long and relatively broad, with membrane and veins pale ochreous. C with minute spinulae not longer than other nne setulae between apices of R 1 and R 2+3. R 2+3 very long, bent parallel to C and ending usually nearer apex of R 4+5 than does M. R 4+5 very slightly bent; M long and almost straight. Discal cell (dm) medium-sized, strongly widened distally; r-m situated distally to middle of dm cell. CuA 1 slightly bent and ending near, A 1 ending far, from wing margin. Anal lobe large; alula also well developed, relatively broad. Wing measurements: length 2.38–2.82 mm, width 0.79–0.99 mm, Cs 3: Cs 4 = 0.76–1.00, r-m\ dm-cu: dm-cu = 1.67–2.09. Haltere yellow, with large pale yellow knob.

Abdomen dark to blackish brown; terga more shining; sterna also dark brown but more densely greyish brown microtomentose and duller. Also T1 and T2 more microtomentose and less lustrous than other preabdominal terga. T3–T5 large, subequal in length and reaching far on ventral side of abdomen, all shortly setose. Preabdominal sterna narrow, becoming wider posteriorly, S5 largest and widest posteriorly. Postabdomen strongly sclerotized, shining blackish brown; T6 well developed, well sclerotized, forming brown, bare, transversely band-like sclerite. S6, S7 and S8 partly fused. S6 almost as long as S7, dark-margined anteriorly and usually both with 2 small setae; S8 long (as typical for Fungomyza ), situated dorsally and more setose on posterior half.

Genitalia. Epandrium ( Figs 36, 38 ) dark brown, higher and wider than long, with more and stronger setae than in F. albimana , 3 pairs of laterodorsal setae longer and thicker than others. Anal nssure small, roundly triangular ( Fig. 36 ); cerci below it also relatively small, each with a number of rather small setae including 2 longer ones and with microtomentum restricted only to posterior side (cercus laterally without microtomentum). Medandrium high, broad ventrally and strongly narrowed dorsally ( Fig. 36 ) although less than in F. albimana . Gonostylus ( Figs 36–38 ) elongate suboblong but with strongly projecting and incurved posteroventral corner bearing 2 small teeth on apex and with microtomentum restricted to a central area of outer side and setae mainly arising on inner side at posterior margin. Hypandrium ( Fig. 38 ) relatively robust, well sclerotized but without anterior nat, dorsally projecting lobes. Pregonite ( Fig. 38 ) large, nat, fused to hypandrium, ventrally thickened and dark but, in contrast to F. albimana , without posterior projection, and with 3 setae in anterior and 2 in posterior group. Postgonite ( Fig. 38 ) simple, slender, pale, slightly bent, distinctly shorter than in F. albimana , with anterior setula in distal third, several grain-like sensillae on outer side and blunt apex. Transandrium well sclerotized, straight medially, with dorsally bent lateral parts and ventromedially carrying distinct (though pale-pigmented) forked caudal process ( Fig. 40 ); basal membrane below caudal process with numerous dense short spines. Aedeagal complex ( Fig. 41 ) with short phallophore having somewhat projecting anteroventral corner. Distiphallus bind and large, composed of largely membranous saccus and heavily sclerotized nlum. Saccus proximally sclerotized but these sclerites asymmetrical, enlarged distally on right side; membranous part of saccus relatively small and unarmed, without distinct spines or setulae. Filum formed by 2 dark band-like sclerites being closely attached in the middle and fused apically; apex of nlum ( Fig. 39 ) slender, nattened and pointed but structurally similar to that of F. albimana . Aedeagal part of folding apparatus ( Fig. 41 ) provided with elongate striae and grain-like tubercles in outer wall. Connecting sclerite ( Fig. 41 , cs) poorly delimited and weakly sclerotized. Phallapodeme ( Figs 38 , 41 ) medium-sized, similar to that of F. albimana , with shortly forked base, robust apical part and large ventral fulcrum. Ejacapodeme ( Fig. 41 ) small, suboblong, with slender ventral projection lying in wall of ejaculatory duct.

Female. Similar to male unless mentioned otherwise. Total body length 2.58–3.18 mm. Face, parafacialia and gena darker, orange yellow to orange ochreous; clypeus darker, brown. Antenna sometimes (North Carolina: Raleigh) more extensively darkened on the lateral surface, reaching ventral margin in apical half. Legs less distinctly variegated. Ctenidial spine on f 1 slightly shorter than in male. f 3 without posteroventral thickened setae. Wing measurements: length 2.58–3.30 mm, width 0.87–1.17 mm, Cs 3: Cs 4 = 0.81–0.97, r-m\dm-cu: dm-cu = 1.53–2.19. Preabdominal terga broader and more transverse, far reaching on ventral side of abdomen. T2–T4 shortly setose; T5 somewhat tapered posteriorly and with distinctly longer setae at posterior margin. Preabdominal sterna slightly narrower than in male, with short and nne setae.

Postabdomen ( Figs 42, 43 ) telescopically retractible and strongly tapered caudally. T6 broadly transverse but very tapered posteriorly, dark, shortly setose. S6 narrow, distinctly longer than broad, setose in posterior half, relatively dark. 6th spiracle situated at anterior corner of T6 ( Fig. 43 ). T7 not fused with S7, markedly narrower than T6 and conically narrowed posteriorly, dark and heavily sclerotized, with longer setae only at posterior margin. S7 as long as S6 but distinctly narrower, with longer and denser microtomentum and long nne setae (more than in F. albimana ) on posterior half, brown except for pale posterior fourth. 7th spiracle situated in front of anterior corner of T7. Intersegmental membrane (also dorsally) between 7th and 8th segment with long distinct pubescence. T8 ( Fig. 42 ) markedly shorter than in F. albimana , distinctly transverse, lighter than T7, without microtomentum and nnely setose. S8 ( Fig. 43 ) more or less divided medially, posteriorly curved dorsally and deeply invaginated into 8th segment (see also Fig. 44 ), strongly microtomentose apart from bare invaginated posterodorsal parts. Internal structures of the female genital chamber (uterus) better sclerotized than in F. albimana , with 2 pairs of partly fused posterior sclerites attached to invaginated parts of S8 ( Figs 44, 45 ) and 1 poorly visible (seemingly incomplete), unpigmented, anterior looped structure; ducts of accessory glands slender, transversely ringed; accessory gland small; ventral receptacle ( Fig. 44 ) large, hyaline membranous, elongate vesicular and similar to that of F. albimana except for terminal projection being short and blunt apically. Spermathecae (1+1) cup-like (not pyriform), with narrower base covered with nne spinulae terminated with usual stalked globuli; distal part broader and provided with broad, deep apical invagination ( Fig. 46 ); spermathecal ducts short, without terminal cervix, hyaline near insertion into body of spermatheca. T10 ( Fig. 42 ) narrowly pentagonal with somewhat bulging sides, and bare apart from usual pair of dorsal setae; apical portion depigmented leaving pigmented basal two-thirds medially and narrowly emarginate between bulging sides to near level of setal pair. S10 ( Fig. 43 ) larger than T10, relatively nat with doubly emarginate anterior margin, also bare except for setae and sparse microtomentum at posterior margin. Cerci long and slender (more robust than in F. albimana ), with rich setae that are longest apically.

Discussion. Fungomyza buccata is the only Nearctic representative of Fungomyza . It closely resembles the W. Palaearctic F. albimana both as regards structures of the male genitalia (eg. form of epandrium, small cercus, dorsally tapered medandrium, robust pregonite, simple slender postgonite, forked caudal process of transandrium, relatively small saccus; similar nlum of distiphallus and ejacapodeme) and the female postabdomen (eg. T6, T7, S6, S7, S8, intersegmental pubescence, T10, ventral receptacle, terminal invagination of spermatheca). Most of these shared features are synapomorphic and four of them were used to demonstrate the sister-species relationships of these taxa, see ROHÁĆEK (2009a: Fig. 139 ).

Fungomyza buccata differs distinctly from F. albimana in a number of external and genitalic features, however, including the following: anterior ors longer; frontal triangle short; eye less oval; gena unusually high (probably the highest in all described Anthomyzidae ); legs differently variegated (e.g. f 1 brown except for both ends, 2 apical segments of all tarsi darkened, f 2 and f 3 darkened in distal half, etc.); gonostylus with projecting posteroventral corner and reduced microtomentum; pregonite without posterior projection; saccus of distiphallus without spinulae or setulae; nlum shorter, with narrower apex; female T8 short and transverse; internal sclerites of female genital chamber distinct and spermathecae more rounded. It is also more robust and has longer wings on the average than F. albimana .

It is to be remarked that an additional species, Reliquantha variipes from Great Britain, is externally strikingly similar to F. buccata (including the variegated legs and cephalic chaetotaxy). It differs from F. buccata very distinctly in the male and female postabdominal structures (see ROHÁĆEK 2013c) and also in lacking the ctenidial spine on f 1 and in having a well-developed subvibrissa, short prs and only 2 setae on the ventral corner of the sternopleuron.

Biology. A male specimen collected by Steve Marshall in Florida was caught on the sporocarp of a white fungus ( Fig. 33 ) growing on a well-rotted, partially buried log in a sandy, partly wooded, habitat. It is therefore probable that F. buccata also develops in fungi like its European sister species. Adults were mainly obtained in autumn (in October – 5 specimens, November – 4 specimens, December – 4 specimens) ; only one female was captured in May. Together this suggests an association with sporocarps of fungi which mainly grow in autumn ( ROHÁĆEK & BARBER 2004).

Distribution. This uncommon species is widespread in the eastern United States of America: Alabama (new record), District of Columbia, Florida, Georgia, Maryland, New York, North Carolina, South Carolina, Virginia ( ROHÁĆEK & BARBER 2004, and Table 2, Figs 600 , 603 ).

Figures

Figs 33–34. Fungomyza buccata Roháček & Barber, 2004, paratypes. 33 – paratype male sitting on fungus, body length ca. 2.6 mm; 34 – wing, paratype female, wing length 2.9 mm. Photo by S. A. Marshall (Fig. 33) and K. N. Barber (Fig. 34). Adapted from ROHÁĆEK & BARBER (2004: Figs 13, 14).

Figs 35–38. Fungomyza buccata Roháček & Barber, 2004, male. 35 – head, laterally; 36 – external genitalia, caudally; 37 – gonostylus, posterolaterally (widest extension); 38 – whole genitalia, laterally. Fig. 35 based on holotype, others on paratype. Scales = 0.3 mm (Fig. 35) and 0.1 mm (others). Adapted from ROHÁĆEK & BARBER (2004: Figs 1–4). For abbreviations see p. 11.

Figs 39–41. Fungomyza buccata Roháček & Barber, 2004, paratype male.39 – apex of nlum of distiphallus, ventrally; 40 – transandrium and basal membrane, caudally; 41 – aedeagal complex, laterally. Scales = 0.05 mm (Fig. 39) and 0.1 mm (others).Adapted from ROHÁĆEK & BARBER (2004: Figs 5–7). For abbreviations see p. 11.

Figs 42–46. Fungomyza buccata Roháček & Barber, 2004, paratype female. 42 – postabdomen, dorsally; 43 – the same, ventrally; 44 – female genital chamber and 8th segment, laterally; 45 – internal sclerites of female genital chamber, ventrally; 46 – spermathecae. Scales = 0.2 mm (Figs 42, 43), 0.1 mm (Figs 44, 45) and 0.05 mm (Fig. 46). Adapted from ROHÁĆEK & BARBER (2004: Figs 8–12). For abbreviations see p. 11.

Figs 139–145. Arganthomyza bivittata Roháček & Barber, 2013, paratype female (Canada: Ontario). 139 – female genital chamber and apex of postabdomen, laterally; 140 – spermatheca; 141, 142 – ventral receptacle, whole laterally (141) and apex ventrally (142); 143 – spermatheca; 144 – internal sclerites, laterally; 145 – the same, ventrally. Scales = 0.1 mm (Fig. 139) and 0.05 mm (others). For abbreviations see p. 11. Adapted from ROHÁĆEK & BARBER (2013: Figs 93–99).

Fig. 600. Map of North America showing unique distributions of six species representing Clusters 5 to 10. Cluster 5: Anthomyza occidentalis sp. nov.; Cluster 6: A. concolor (Thomson, 1869); Cluster 7: A. furvifrons sp. nov.; Cluster 8: Fungomyza buccata Roháček & Barber, 2004; Cluster 9: Arganthomyza acuticuspis Roháček & Barber, 2013; Cluster 10: Arg. socculata (Zetterstedt, 1847). Many of the west coastal localities are shared between A. occidentalis and A. concolor with several records of the latter not visible.See “Distributional patterns” for explanation of Clusters.

Fig. 603. Phylogeny and its biogeographic implication for species of the genus Fungomyza.