Ssymank, Axel & Jordaens, Kurt, 2021, Description of the female of Syrittosyrphus opacea Hull, 1944 (Diptera, Syrphidae, Eristalinae) with additional notes on the genus, African Invertebrates 62 (1), pp. 339-353: 339
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Genus Syrittosyrphus Hull
Syrittosyrphus opacea Hull- Smith and Vockeroth (1980): 508; Dirickx (1998): 137; Whittington (1998), 39: 193; Whittington (2003), 10: 603.
The genus differs from any other genus of hoverflies in the following combination of characters: scutellum with deep rim and fringe of pile ventrally, metasternum pilose, coxae with long pile, all sternites with long pile, wing cell r1 widely open, wing vein R4+5 deeply sinuate, stigmal cross-vein present, petiole of anal cell long.
Syrittosyrphus opacea Hull : Holotype (Fig. 1View Figure 1), male, “Holo-//type” "Cape Province://Somerset East,// November 1930 " " S. Africa. // R.E. Turner. //Brit. Mus.//1930-593." " Holotype // Syrittosyrphus // Syrittosyrphus opacea //Hull" [red label, handwritten] [32.72°S, 25.58°E; coordinates taken from Gazetteer and therefore approximate] [ NHMUK].GoogleMaps
South Africa • 1 ♂; Cathedral Peak Area , KwaZulu-Natal; 28°57'S, 29°12'E; 16 Dec 1977; J.G.H. Londt leg.; NMSA-Dip 53518 ( NMSA)GoogleMaps • 1 ♀; Nkandla Forest Reserve , KwaZulu-Natal; 28°42'36"S, 31°8'29"E; 12 Jun 2003; A.J. Armstrong leg.; NMSA-Dip 65136 ( NMSA)GoogleMaps • 1 ♀; Royal Natal National Park , KwaZulu-Natal; 28°41'S, 28°39'E; I.1971; H. Townes leg.; NMSA-Dip 51877 ( NMSA)GoogleMaps • 1 ♀; Hlatikulu Mountain, Monks Trail Bush edge, KwaZulu-Natal; 28°13'S, 30°01'E; 17 Mar 1997; J.G.H. Londt leg.; NMSA-Dip 015878 ( NMSA)GoogleMaps • 1 ♀; Forest Glens, N. Drakensberg , Limpopo Province; 23.96951°S, 29.91860°E; Dec 2001; J. Swaye leg.; NMSA-Dip 015879 ( NMSA)GoogleMaps • 1 ♀; 10 km E of Bedford, on Adelaide-Bedford Road, roadside Karoo bush, Eastern Cape; 32.6667S, 26.2833E (Gazetteer); [date unknown]; D. Barraclough & C. Barraclough leg.; NMSA-Dip 049495 ( NMSA)GoogleMaps • 1 ♀; Royal Natal National Park, Day Visitor Car Park , KwaZulu-Natal; 28°41'25.4"S, 28°56'53.9"E; 1410 m a.s.l.; 4 Dec 2012; A. Ssymank leg.; (ASPC)GoogleMaps • 1 ♂; Karkloof Nature Reserve , KwaZulu-Natal; 29°17'54.53"S, 30°18'21"E; 13 Nov 2018, K. Jordaens; KMMA AB59880784; DNA voucher 1179A01 ( KMMA) • not studied, but cited in Horn (2004)GoogleMaps : 1 ♂ from Forest Glens, northern Drakensberg , Limpopo Province; (WBPC) . Zimbabwe • 1 ♀; Vumba ; 12 Mar 1964; D. Cookson leg.; NMSA-Dip 32362 ( NMSA) • 1 ♂; N Vumba ; 6 Feb 1966; D. Cookson leg.; NMSA-Dip 32374 ( NMSA) .
Body length: 15.0 mm (n = 1); wing length: 11.4 mm (n = 1).
Head [Figs 1View Figure 1 and 4AView Figure 4; see also fig. 6G and H, p.15 in Hippa (1990)]: Eyes holoptic; eye contiguity shorter than length of ocellar triangle. Face yellow with median Y-shaped brown non-trichose band, yellow parts densely pale pollinose; pale setose. Gena ochre with brownish-black band from oral margin to eye margin. Clypeus subquadrate, broad, dark brown, greyish microtrichose. Lunule brownish-orange. Frons above antennae dark brown shining, non-pollinose, inflated, with a small central round depression. Frontal triangle brownish to black setose on anterior inferior part, with pale setae dorsally, non-pollinose, except narrowly along eye margin. Ocellar triangle equilateral, ocelli reddish, bare. Occiput pale greyish microtrichose; pale setose. Antennae with scapes and pedicel brownish, non-pollinose; postpedicel twice as long as wide, yellowish, densely greyish pollinose; arista yellow, bare, about 2-2.5 times as long as postpedicel.
Thorax (Figs 1View Figure 1, 2AView Figure 2 and 3AView Figure 3): Dark brown to black, scutum yellow pollinose along margins and suture and in anterior part, also along median line, leaving large brownish-black non-pollinose areas with blackish setae. Scutellum yellow, width to length ratio 2.5:1, with premarginal sulcus, long yellow densely setose (setae ca. 1/3-1/2 length of scutellum); subscutellar fringe well developed with dense long yellow setae of ca. 0.45 mm. Pleurae brownish, mostly densely grey pollinose; postpronotum with a small pronounced non-pollinose bulge leading into an elevated rim of the scutum, with yellow and a few black setae intermixed; anterior anepisternum, posterior part of proepimeron and anterior part or posterior anepisternum bare; proepisternum, posterior part of anepisternum and anterior anepimeron with long yellow setae; katepisternum with posteriodorsal tuft of long setae and ventrally setose; meron, metepimeron, katepimeron, katatergite, posterior anepimeron, except for some short microsetae, bare; metasternum densely long yellow setose. Ampulla yellow. Plumula yellowish. Thoracic spiracles with whitish to ochre vestiture.
Legs [Figs 1View Figure 1, 2AView Figure 2, 3AView Figure 3 and 4CView Figure 4: see also fig. 6E and F, p. 16 in Hippa (1990)]: reddish-brown, tibia with basal 1/3 to 1/2 yellow. Mesofemur posteriorly grey pollinose, anteriorly with a broad median pollinose band; short adpressed yellowish setae; tarsae ventrally with short stout black setulae. Mesotibia abruptly broadened in apical 1/4. Mesofemur posterolateral with a row of longer whitish setae (length ca. 1/2 diameter of mesofemur). Mesotibia slightly dilated apically with apicoventrally a short comb of short black stout setulae and a small pointed tooth on the opposite side. Metacoxa (Fig. 4CView Figure 4) with two black spurs of ca. 1 mm long. Metafemur with posterolateral row of longer whitish setae (length ca. 1/3 of diameter of metafemur); ventrobasally with a low ridge carrying a black comb of short stout black setulae; apicoventrally with a depression that carries a ridge with a row of black stout setae on the anterior side. Metatibia yellow, apical 2/3 brownish; dilated towards apex, apical half carinate posteriorly; anteriorly with an oblique depression at 1/4 from apex.
Wing (Figs 1View Figure 1, 4DView Figure 4): hyaline, along anterior margin yellowish with darkened patches below pterostigma extending to cross-vein r-m, wing tip slightly darkened. Anal cell very long. Cell r1 widely open, in apical half widened and close to wing margin suddenly narrowed, ending at wing margin. Vein R4+5 with a deep oblique sinuate loop into cell r4+5. Spurious vein well developed, as thick as other veins, extending into cell r4+5. Anal cell microtrichose with basal area bare. Basal half of wing up to cross-vein r-m with sparse microtrichia, with bare areas along veins; apical 1/3 of wing (including entire cell r4+5) densely microtrichose. Calypters white with an orange-brown margin, long yellow-white pilose. Halteres yellow-brown.
Abdomen (Figs 1View Figure 1, 2AView Figure 2, 3AView Figure 3): long and conical; setae from tergites I to IV mostly yellowish short and adpressed, only on lateral margins longer yellow setae. Tergite I yellow to ochre, densely greyish pollinose with the exception of a narrow non-pollinose posterior margin. Tergite II with large orange maculae, with lateral, anterior and posterior margins brownish to black; slightly darkened along median line; mostly non-pollinose. Tergite III narrowly yellow along anterior margin, otherwise dark brown; with sparse, but distinct yellowish to grey pollinosity, pollinosity more dense along median line and towards posterior margin. Tergite IV brownish-black, only anterior part of median line greyish pollinose. On tergites II-IV, the dark coloured parts have short blackish setulae. Hypopygium with brownish-black long setae. Sternite I brownish, densely grey pollinose. Sternite II yellow with black median line; only along anterior margin whitish pollinose. Sternite III anterior and posterior margin yellow, with central broad brownish-black fascia, uniform, but weak pollinose. Sternites I-III with very long dense setae of ca. 2 mm length. Sternite IV brownish-black, distinctly greyish pollinose laterally, with long setae that form a dense comb along lateral margin, leaving a median non-pollinose, almost bare, area of approx. 1/4 to 1/3 of sternal width.
Genitalia [Fig. 5A, BView Figure 5; see also fig. 6A and B, p. 15 in Hippa (1990)]: Epandrium with surstylus dorsally from halfway strongly curved downwards, pointed, ventrally with subtriangular expansion, dorsally and ventrally long yellow-brown pilose. Hypandrium very large and ventrally broadly expanded; aedeagus with a ventral sharp tooth. Cerci broad, club-shaped; on posterior and ventral side long yellow-brown pilose.
Body length: 14.0 mm (n = 1); wing length: 11.4 mm (n = 1)
Similar to male, except for distinct sexual dimorphism. Frons with a broad greyish pollinose band with grey setae (Fig. 4BView Figure 4). Ocellar triangle and upper part of frons brownish-black, non-pollinose, brownish to black setose (Fig. 2BView Figure 2). Legs (Figs 2BView Figure 2 and 3BView Figure 3): protibia less broadened in apical third. Mesoleg without black setal comb on tip of tibia. Metaleg: coxa without long spur; femur with very low ventral bump, with some stout black setae; basoventral patch of black setae missing; no long pale setae posterolaterally. Abdomen (Figs 2BView Figure 2, 3BView Figure 3): Tergite V black, non-pollinose, black setose, but shorter than in male. Sternites with long pale setae much shorter and less dense than in male (1.5 mm on sternite II, 0.65 mm on sternite V); sternite III + IV with scattered longer setae only; sternite V with only a few longer setae. Genitalia (Fig. 6View Figure 6) compact, tergite 7 approx. 1.5 × as broad as long, tergite 8 approx. as long as broad, posteriorly rounded, without lateral apodemes, with very long evenly distributed long yellow-brown pile; epiproct broad, with two rounded anterior areas and with a single basal area with two triangular large apodemes, with a granulated small lateral lobe to the epiproct; sternite 8 large, with an unusual ventral modification, ventrally concave; sternite 9 with conspicuous pigmentation at apical margin; cerci rounded, semi-circular, apical end gently curved inwards, long yellow-brown pilose.
South Africa ( Hull 1944; this study), Zimbabwe ( Whittington 1998) (Fig. 7View Figure 7).
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