Anthomyza elongata, Roháček, 2020

Roháček, Jindřich, 2020, Anthomyzidae (Diptera) of Taiwan: new species but no new records, Acta Entomologica Musei Nationalis Pragae 60 (1), pp. 269-290 : 284-286

Anthomyza elongata sp. nov.

( Figs 26, 27 , 48 ¯55)

Type material. HƟĿƟŦYPൾ: ♀, labelled:“ TAIWAN,Ali-shan [= Alishan], 2584 m, Oct. 31, 1985, K. Kanmiya” and “ Holotypus ♀, Anthomyza elongata sp. n., J. Roháček det. 2019” (red label). The specimen is intact ( Fig. 27 ), dry mounted on a pinned triangular card ( SMOC). PARAŦYPൾඌ: 2 ♀♀, with same label data as for the holotype, only second (type) label is yellow with “ Paratypus ”.Abdomen of each female cleared, dissected and preserved in glycerine in a pinned plastic tube, in one of them together with one wing (used for photography) ( SMOC).

Description. Male unknown.

Female. Large species, total body length 3.25–3.41 mm; general colour blackish brown (thorax) to brown (abdomen), very sparsely greyish microtomentose and hence distinctly shining ( Fig. 27 ). Only anterior and ventral parts of head, ventral corner of sternopleuron and abdominal sterna yellow or ochreous.

Head as long as high, with slightly projecting frons and receding face, thus somewhat angular in profile. Occiput dorsomedially concave, blackish brown but ventrally (below foramen) yellow; occiput sparsely darkgrey microtomentose, only the medial stripe running from ocellar triangle to foramen bare and shining. Frons dark brown, only anterior fourth to third yellow, largely microtomentose. Frontal (including ocellar) triangle and orbits silvery-grey microtomentose and somewhat glittering, contrasting with dull blackish-brown stripes between them meeting in front of anterior corner of frontal triangle. Orbit yellow only anteriorly (up to middle ors), brown between middle and posterior ors, dark brown and more shiny posterior to the latter. Frontal triangle relatively broad, reaching only to anterior two-fifths of frons. Frontal lunule small, narrow and depressed, yellow. Face narrow, medially concave, light yellow with whitish microtomentum; parafacialia and gena yellowish white and silvery-white microtomentose, both bordered by relatively wide, ochreous-yellow marginal stripe; postgena largely pale yellow and whitish microtomentose, concolourous with ventral part of occiput; mouthparts dark yellow to ochreous. Cephalic chaetotaxy: pvt of moderate length, thin and crossed; vti very long, by far the longest of cephalic setae; vte shorter than oc; 3 moderately long but relatively thin ors, becoming shorter anteriorly, posterior ors as long as vte; middle ors arising closer to anterior ors than to posterior ors; no microsetula in front of the anterior ors; 2–4 pairs of relatively long, medial microsetulae in the yellow anterior part of frons; 1 or 2 setula(e) behind vte slightly longer than dorsal postoculars; the latter sparse (5 or 6), in single row but occiput with several additional scattered setulae; postgena with a few small setulae, also 2 short and weak posteroventral setae; 1 relatively weak vi, about as long as middle ors but finer; subvibrissa reduced, less than half length of vi and only slightly longer than fine and sparse (3 or 4) peristomal setulae. Palpus elongate, slender, yellow, with 1 distinct black preapical seta and 3 or 4 shorter, dark ventral setulae. Eye broadly ovoid (in contrast to most of relatives), with longest diameter oblique and only about 1.3 times as long as the shortest. Shortest genal height about 0.17 times as long as shortest eye diameter. Antenna geniculate, yellow to orange; 1st flagellomere with very short, white pilosity on anteroventral margin (about as long as that of arista). Arista with pale-brown basal segments and blackish terminal part, 1.9–2.0 times as long as antenna, very shortly ciliate.

Thorax slightly narrower than head, blackish brown dorsally to brown laterally, very sparsely grey microtomentose and shining (its pleural part subshining); only sternopleuron ( Fig. 27 ) gradually lightened from brown dorsally to yellow ventrally (sometimes with only ventral corner yellow); hypopleuron also often paler brown, particularly ventrally. Thoracic chaetotaxy (all macrosetae relatively thin, most dark but some thinner ones pale-pigmented): 1 hu, as long as posterior npl; 2 npl (anterior markedly longer); 1 weak prs, shorter and finer than hu; 1 weak sa (as long as prs); 1 longer pa; 2 postsutural dc, anterior thinner and about two-thirds length of posterior dc (longest thoracic seta); 6–8 dc microsetae in front of anterior dc; 4 irregular and incomplete rows of ac microsetae on suture, only 2 medial rows more posteriorly (between dc), not reaching to level of posterior dc; 2 sc, laterobasal small and weak (shorter than prs), apical almost as long as posterior dc; 1 minute, upcurved and pale ppl; 2 dark stpl, posterior long, anterior about two-thirds of posterior and thinner; no setulae in dorsal half of sternopleuron; its ventral, yellow corner with 4 longer yellow setae. Scutellum rounded triangular, very slightly convex to flat dorsally. Legs yellow, with coxae whitish yellow, only last tarsal segments or their distal half brownish ( Fig. 27 ). f1 with very short ctenidial spine, no more than half maximum width of t1 and with long fine setae in posteroventral and posterodorsal rows; t2 with short ventroapical seta, only slightly longer than distal width of t2; f2, f3, t1, t3 and all tarsi simply setulose, only hind basistarsus with a few ventrobasal setulae longer. Wing ( Fig. 26 ) very long, relatively narrow, with pale ochreous veins and membrane. C with sparse spinulae between apices of R1 and R2+3. R2+3 very long, running parallel to C, with apex slightly upcurving; R4+5 very slightly bent, more or less parallel to M apically. Cell dm long and very narrow, distally widened, with r-m situated in its proximal two-fifths. Apical portion of CuA1 distinctly longer than dm-cu and almost reaching wing margin; A1 short, ending far from margin. Alula small, narrow. Wing measurements: length 3.89–4.09 mm, width 1.15–1.21 mm, Cs3: Cs4 = 0.95–1.21, rm\dm-cu: dm-cu = 2.79–3.34. Haltere yellow to ochreous, with knob slightly darker.

Abdomen. Preabdominal terga brown to dark brown (darker laterally), relatively densely setose, with sparse greyish microtomentum and relatively shining ( Fig. 27 ) but slightly less so than mesonotum. T1 only laterally fused with T2, distinctly narrower and shorter than T2; T2–T5 large, transverse, reaching onto ventral side of abdomen, subequal in length. T3 and T4 slightly wider than T2 and T5. Preabdominal sterna ochreous to pale brown, very narrow; S1 shortest, transverse and bare, S2–S5 with sparse, fine setae; S2 darkest and with brown anterior marginal stripe; S2–S4 distinctly longer than wide; S3 slightly narrower than S2 or S4; S5 only slightly longer than wide, wider than S4, with unpigmented posterior margin ( Fig. 51 ).

Postabdomen ( Figs 49–51 ) elongately conical, more tapered laterally ( Fig. 50 ) than dorsoventrally ( Fig. 49 ). T6 large, almost as wide as T5 anteriorly but strongly tapered posteriorly ( Fig. 50 ), entirely blackish brown, with relatively dense but fine setae. S6 relatively narrow (but larger than that of A. caesarea ), about as long as wide ( Fig. 51 ), somewhat narrower posteriorly, ochreous, with a number of fine long setae. Tergosternum T7+S7 dorsally shorter (shortest dorsomedially) and blackish brown except for small anteromedial pale-pigmented area ( Fig. 50 ); ventrally longer and its dark anteroventral parts extended to almost meet medially ( Fig 51 ), posteromedially with pale-brown, more or less distinctly delimited, narrowly subtriangular area (= remnant of S7) being setose in posterior two-thirds and distinctly micropubescent anteriorly ( Fig. 51 ). T8 elongate, narrow, semicylindrical and pale-pigmented as in A. flavosterna , with fine setae at posterior and lateral margins; S8 shorter than T8, broadly divided medially into two convex to bulging, pale-brown and shortly setose sclerites (see Figs 51, 52 ). Genital chamber with reduced internal sclerotization ( Figs 52, 54 ) as in A. caesarea , with single pair of sclerites longer but also submembranous and poorly delimited, situated anterior to the annular sclerite; annular sclerite well developed and similar to that of A. caesarea but broader in ventral view ( Fig. 54 ). Ventral receptacle ( Figs 52, 53 ) also resembling that of A. caesarea , having basal part narrower and hyaline, middle part wider and darkened, but the latter terminally smooth, pale and projecting in longer vermicular terminal part with apex shortly twisted ( Fig. 53 ); remnants of accessory gland not seen, probably small, on simple slender duct. Spermathecae (1+1) most similar to those of A. caesarea but short pyri- form ( Figs 48, 55 ), with a few, and less distinct, transverse striae and reduced (both in number and size) tuberculiform spinulae; cervix smaller and paler. T10 small ( Fig. 50 ) but longer and less transverse than that of A. flavosterna , with usual medial pair of longer setae, lacking micropubescence. S10 ( Fig. 51 , retracted) only slightly wider but distinctly longer than T10, elongately rounded pentagonal, with fine micropubescence and marginal setae. Cercus relatively short and robust ( Figs 49, 50 ), most similar to that of A. flavosterna but pale-pigmented and its setae finer.

Discussion. Anthomyza elongata sp. nov. is another member of the Anthomyza flavosterna group. It resembles the above species, A. caesarea sp. nov. and also A. sp. nov. near elongata by its large size but differs from both these species by its blackish-brown thorax, including its pleural part with only the ventral corner of the sternopleuron yellow. In the latter character, it resembles the much smaller A. flavosterna but differs from the latter in having a broad frontal triangle, a broadly ovoid eye and the last tarsal segments brownish. It is also recognizable by the form of structures of the female postabdomen, many of which are intermediate between those of A. flavosterna and A. caesarea sp. nov.: the tergosternum T7+S7 with a distinct remnant of S7, short T10 and short robust cerci resemble more those of A. flavosterna , while the narrow S6, submembranous paired sclerites and shape of the annular sclerite in the genital chamber, and pyriform spermathecae are more similar to those of A. caesarea sp. nov. However, the detailed construction of all the above-discussed structures is more or less different (see description) from those of these two species. Considering the formation of the postabdominal sclerites, A. elongata sp. nov. seems to be closest to an unnamed species diagnosed below, viz. A. sp. nov. near elongata. The differences between these two species are enumerated below in the diagnosis of the latter species. The long and posteriorly tapered 6th segment (including T6, Fig. 50 ) seems to be unique to A. elongata sp. nov.

Etymology. This species is named for its long and slender body and wings (elongatus = elongate, Latin adjective).

Biology. Anthomyza elongata is known only from 3 females collected in October in the Alishan mountain range at 2584 m a. s. l.

Distribution. Taiwan: Chiayi County.

Figures

Figs 22–27. Anthomyza species from Taiwan.22–25 – A. caesarea sp. nov., male and female: 22 – male holotype before dissection, laterally (body length ca. 3.3 mm); 23 – female paratype before dissection, laterally (body length ca. 3.4 mm); 24 – wing, female paratype (length ca. 3.9 mm); 25 – female paratype before dissection, laterally (body length ca. 3.5 mm); 26–27 – A. elongata sp. nov., female: 26 – wing, female paratype (length ca. 3.7 mm); 27 – female holotype, laterally (body length ca. 3.4 mm). Photos by J. Roháček.

Figs 48–55. Anthomyza elongata sp. nov., female paratype. 48 – spermatheca; 49 – postabdomen, laterally; 50 – postabdomen with 5th abdominal segment, dorsally; 51 – the same, ventrally; 52 – genital chamber with 8th abdominal segment, laterally; 53 – ventral receptacle, subventrally; 54 – internal sclerites, ventrally; 55 – spermatheca. Scales = 0.2 mm (Figs 49–51), 0.03 mm (Figs 48, 55), 0.05 mm (Fig. 53) and 0.1 mm (others).