Chrysotus spectabilis (Loew)

Capellari, Renato Soares & Amorim, Dalton De Souza, 2010, Re-description and new combination of five New World species of Chrysotus Meigen, with comments on the Neotropical genus Lyroneurus Loew (Diptera: Dolichopodidae), Zootaxa 2520, pp. 49-65 : 57-60

Chrysotus spectabilis (Loew)

( Figs. 11–15 , 22 )

Diaphorus spectabilis Loew, 1861: 57 . Type-locality: USA, District of Columbia. Distr. – Eastern USA to Argentina. Type: ♂, MCZ.

Diaphorus exunguis Thomson, 1869: 506 ; Becker, 1922: 173.

Diaphorus approximatus Aldrich, 1896: 321 ; Aldrich, 1901: 345; 1902: 85.

Chrysotus spectabilis (Loew) ; Robinson & Vockeroth, 1981: 628.

Diagnosis. Male: Eyes approximate above antennae, obliterating frons; vt absent; femora mainly brown, except for apices; pulvilli I and II as long as t5, claws present; abdominal sternites with long vestiture, St8 without striking bristles. Hypandrium strongly constricted after emerging from epandrium, followed by an intumescence with serrate dorsal surface; cercus subtriangular.

Material examined: DOMINICA, Clarke Hall, 1 ɗ, 07.vi.1966, G. Steyskal leg.; 1 ɗ, 1–10.iii.1965, W.W. Wirth, leg., light trap; 1 ɗ, 21–28.ii.1965, W.W. Wirth, leg., light trap; 1 ɗ, 11–20.ii.1965, W.W. Wirth, leg., malaise trap; 1 Ψ, 21–31.i.1965, W.W. Wirth leg., malaise trap; 1 Ψ, 1–10.ii.1965, W.W. Wirth, leg., light trap ( USNM, identification: H. Robinson).

Re-description. Male. Body length: 3.2–3.6 mm. Wing: 2.7–2.9 mm long, 1.2–1.3 mm wide. Head. Frons very narrow (around half the ocellar mound width), obliterate by nearly holoptic eyes (mssc), dark green, covered by fine silvery pruinosity; face broad, dark green, with some bluish reflections covered by silvery pruinosity, sometimes with few, not conspicuous, scattered pale hairs; 1 pair of strong, slight divergent, oc and 1 pair of minute poc; vt absent, 1 pair of pavt; a row of pale pocl, dorsal 8 dark, occiput slightly concave, lower surface with many scattered long pale setae. Proboscis dark brown, with fine brownish setae; palpus brownish with black setae. Antenna brown, scape conical, short; pedicel short, with crown of setulae at apex, dorsalmost longer; postpedicel rectangular, clearly pubescent, stylus apical, bi-articulated at base, also pubescent. Thorax. Shining green. Mesonotum around transverse suture, anepisternum and katepisternum with some bronze reflections; bluish shine above on anepisternum and katepisternum; pleura slightly covered by silvery pruinosity. Ac irregularly biseriate, extending to between 4th and 5th pairs of dc; 6 pairs of large dc, except 1st pair small; 1 pre- and 1 sutural ia; 1 pre- and 2 post-sutural sa; 1 large pa with 1 minute anterior seta; 2 npl; anterior end of mesonotum with only few setulae on each side of median suture; 3 pprn, 1 very strong and 2 minute; lower surface of proepisternum with 2 pale setae, ventral one longer; upper surface of proepisternum in front of anterior spiracle bare; scutellum light green, with pair of strong medial scutellars and 1 pair smaller laterad, about 1/3 as long as medial scutellars. Wing ( Fig. 22 ). Membrane somewhat infuscate. C ending at wing apex; R1 ending on basal third of wing; R2+3 not bent anteriorly at distal end; R4+5 and M almost parallel towards wing apex, R4+5 only slightly bent before reaching C; CuAx ratio, 0.6; A1 present, not reaching wing margin; anal angle enlarged. Lower calypter and cilia yellowish; halter yellow. Legs. I: 2.1, 2.2, 1.2, 0.5, 0.3, 0.2, 0.2. II: 2.3, 2.3, 1.2, 0.6, 0.4, 0.2, 0.2. III: 2.8, 2.9, 1.0, 0.7, 0.4, 0.2, 0.2. CxI pale brown; CxII and CxIII brown, trochanters, femora (except apical 1/3–1/4 of FI and extreme tips of FII and FIII) and tarsi except bases; apical 1/3–1/4 of FI, extreme tips of FII and FIII, and tibiae yellow. Anterior surface of CxI covered by many long pale setae, few brownish setae on distal half, outer edge with black setae; anterior surface of CxII with 1 conspicuous lateral seta at base and with diagonal row of black setae descendent internally; lateral of CxIII with 1 long, black basal seta and 1 minute pale seta apically. FI with row of conspicuous pv and row of shorter av; ventral surface of FII with row of sparse setae; anterodorsal surface of FIII covered by many long, curved setae. TI with 1 minute ad at base, ventral surface with short serration; TII with 1 ad at base and 1 shorter pv; TIII with irregular row of dorsal setae, 5–7 larger. Apical tibial setae: 0, 3, 4. Pulvilli I and II slightly developed, as long as t 5 in I and II; claws present in all legs. Abdomen. Shining green, dorsum rather olivaceous, with some bronze reflections, lower margins of Tg2–4 lighter. Tergites covered by long black bristles, those of distal margins longer. St2–4 covered by long pale setae, St4–5 also with few black setae. St8 only with pale setae on distal margin. Hypopygium ( Figs. 11–12 ). Anterior margin of epandrium straight at level of emergence of hypandrium; lateral epandrial lobe not projected, bearing 2 setae, basiventral seta present; surstylus short and stout, 2 strong spines and 1 seta mesally at apex, 1 dorsal seta near middle. Proximal portion of hypandrium with short projection; distal portion, after emerging from epandrium, constricted, followed by intumescence with serrate dorsal surface.

Arms of postgonite slightly longer than anterior proccesses. Cercus short, subtriangular, pale brown. Female. Body length: 3.0– 3.3 mm. Wing: 2.9–3.1 long, 1.1–1.2 mm wide. Very similar to males, except as noted. Frons as wide as face, metallic green with some bluish reflections, covered by silvery pruinosity; clypeal suture evident; 1 pair of strong proclinate vt; palpus blackish. Legs. I: 1.8, 1.9, 1.0, 0.5, 0.3, 0.2, 0.1. II: 2.2, 2.4, 1.4, 0.7, 0.4, 0.3, 0.2. III: 2.5, 2.5, 0.9, 0.7, 0.4, 0.2, 0.2. Femora without conspicuous row of setae. TII with 1 large ad at base, and 1 pd and 1 ventral seta shorter near middle; TIII with 2 ad on basal half and 3–4 pd along length. Terminalia ( Figs. 13–15 ). Anterior margin of Tg6–7 with deep inverted U-shaped incision ( Fig. 15 ). Tg8 and St8 divided into two rod-like sclerites, St8 sclerites connected mesally by sclerotized bridge; dorsal surface of acantophorites (Tg10) with crest of 5 rhomboid spines and 1 lateral seta.

Comments. As also noted by Aldrich (1901), in the material of C. spectabilis studied here the eyes are not always fully holoptic, a condition seen in the illustration by Robinson and Vockeroth (1981: Fig. 7 ). In addition, the wide distribution range of the nominal species, from eastern North America to Argentina, suggests that the question of its conspecificity throughout the Americas should be carefully considered.

Figures

FIGURES 11 – 12. Chrysotus spectabilis (Loew), specimen from Dominica, B. W. I., male hypopygium (11, ventral view; 12, left lateral view). Scale bar: 0.1 mm.

FIGURES 13 – 15. Chrysotus spectabilis (Loew), specimen from Dominica, B. W. I., female oviscapt (13, 15 dorsal view; 14, right lateral view). Scale bars: 0.1 mm.

FIGURES 18 – 25. Wings of Chrysotus and Lyroneurus. 18. C. angustifrons (Robinson) comb. nov., male paratype. 19 – 20. C. maculatus (Parent) comb. nov. (= Diaphorus maculipennis Robinson) (19, male; 20, female). 21. C. robustus (Robinson) comb. nov., male paratype. 22. C. spectabilis (Loew), male. 23. C. wirthi (Robinson) comb. nov., male paratype. 24 – 25. L. adustus (Wiedemann), male. Scale bars: 1.0 mm.

FIGURES 5 – 8. Chrysotus maculatus (Parent) comb. nov. (= Diaphorus maculipennis Robinson). 5 – 6. Male hypopygium, specimen from Nova Granada (5, ventral view; 6, left lateral view). 7 – 8. Female oviscapt, specimen from Nova Xavantina (7, dorsal view; 8, right lateral view). Scale bars: 0.1 mm.