Description of the female of Syrittosyrphus opacea Hull, 1944 (Diptera, Syrphidae, Eristalinae) with additional notes on the genus Author Ssymank, Axel https://orcid.org/0000-0002-8285-5429 Federal Agency for Nature conservation (BfN, II 2.2), Konstantinstrasse 110, 53179 Bonn, Germany ssymanka@bfn.de Author Jordaens, Kurt Royal Museum for Central Africa, Invertebrates Section, Leuvensesteenweg 13, B- 3080 Tervuren, Belgium text African Invertebrates 2021 2021-04-23 62 1 339 353 http://dx.doi.org/10.3897/AfrInvertebr.62.61504 journal article http://dx.doi.org/10.3897/AfrInvertebr.62.61504 2305-2562-1-339 230C8E00FB984059B04ED95090D3B399 130A24C69F5156D0A32BE498458F3FDE Genus Syrittosyrphus Hull Syrittosyrphus Hull, 1944: 203. Type species: Syrittosyrphus opacea Hull, 1944, (by monotypy). Syrittosyrphus opacea Hull- Smith and Vockeroth (1980) : 508; Dirickx (1998) : 137; Whittington (1998) , 39: 193; Whittington (2003) , 10: 603. Differential diagnosis. 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. Examined material. Syrittosyrphus opacea Hull : Holotype (Fig. 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]. Figure 1. Syrittosyrphus opacea Hull, 1944 A dorsolateral view of the male holotype B labels. Other material. South Africa1 ♂ ; Cathedral Peak Area , KwaZulu-Natal ; 28°57'S , 29°12'E ; 16 Dec 1977 ; J.G.H. Londt leg.; NMSA-Dip 53518 (NMSA) 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) 1 ♀ ; Royal Natal National Park , KwaZulu-Natal ; 28°41'S , 28°39'E ; I.1971 ; H. Townes leg.; NMSA-Dip 51877 (NMSA) 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) 1 ♀ ; Forest Glens, N . Drakensberg , Limpopo Province ; 23.96951°S , 29.91860°E ; Dec 2001 ; J. Swaye leg.; NMSA-Dip 015879 (NMSA) 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) 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) 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) : 1 ♂ from Forest Glens , northern Drakensberg , Limpopo Province ; (WBPC) . Zimbabwe1 ♀ ; Vumba ; 12 Mar 1964 ; D. Cookson leg.; NMSA-Dip 32362 (NMSA) 1 ♂ ; N Vumba ; 6 Feb 1966 ; D. Cookson leg.; NMSA-Dip 32374 (NMSA) . Re-description male. (Figs 2A , 3A , 4A, C, D : all from NMSA-Dip 53518). Body length: 15.0 mm (n = 1); wing length: 11.4 mm (n = 1). Head [Figs 1 and 4A ; 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. Figure 2. Syrittosyrphus opacea Hull, 1944 A dorsal view male B dorsal view female. Figure 3. Syrittosyrphus opacea Hull, 1944 A lateral view male B lateral view female. Thorax (Figs 1 , 2A and 3A ): 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 1 , 2A , 3A and 4C : 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. 4C ) 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. Figure 4. Syrittosyrphus opacea Hull, 1944 A head male, frontal view B head female, frontal view C metaleg male, posterior view D right wing male. Wing (Figs 1 , 4D ): 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 1 , 2A , 3A ): 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, B ; 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. Figure 5. Male genitalia of Syrittosyrphus opacea Hull, 1944 A ventral view B lateral view. Abbreviations: cerc, cercus; ep, epandrium; hyp, hypandrium; v, ventral tooth of the aedeagus. Figure 6. Female genitalia of Syrittosyrphus opacea Hull, 1944 A dorsal view B ventral view C lateral view. Abbreviations: ap, apodeme of epiproct; cerc, cercus; ep, epiproct; hyp, hypoproct; ll, lateral lobe to the epiproct; mem, membranous area between epiproct and cerci; st8, sternite 8; st9, sternite 9; tg8, tergite 8. Description female. Figs 2B , 3B , 4B (specimen NMSA-Dip 65136) and 6 (ASPC). 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. 4B ). Ocellar triangle and upper part of frons brownish-black, non-pollinose, brownish to black setose (Fig. 2B ). Legs (Figs 2B and 3B ): 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 2B , 3B ): 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. 6 ) compact, tergite 7 approx. 1.5 x 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. Distribution. South Africa ( Hull 1944 ; this study), Zimbabwe ( Whittington 1998 ) (Fig. 7 ). Figure 7. Distribution of Syrittosyrphus opacea Hull, 1944 in South Africa and Zimbabwe. Red dots: distribution records; green dot: type locality.