A striking new species of Prosoeca Schiner, 1867 (Diptera: Nemestrinidae): An important pollinator from the Bokkeveld Plateau, Northern Cape Province, South Africa Author Barraclough, Id. A. Author Colville, Jonathan F. Author Karolyi, Florian Author Krenn, Harald W. text Zootaxa 2018 2018-10-10 4497 3 411 421 journal article 29170 10.11646/zootaxa.4497.3.5 d8bd4969-2e1c-4875-8368-f620eb7147f8 1175-5326 1455152 72689FA0-574F-4183-B34C-DFF850013C6A Prosoeca marinusi Barraclough sp. nov. ( FigS 1–15 ) Type material (all in SAM): South Africa: Northern Cape: HOLOTYPE: ♂: “South Afr., C.P. / 3119 AC / Nieuwoudtville ReServe / 5 Aug 1988 / K. Steiner 2139”; “HoSt PlantS / Lapeirousia / oreogena / Time: 1030- 1200”. PARATYPES: 1♂, same data but “K. Steiner 2136”; 1♂, same data but “K. Steiner 2137”; 1♀, same data but “K. Steiner 2138”; 1♂, same data but “K. Steiner 2140”; 1♂, same data but “K. Steiner 2141”; 1♂, same data but “K. Steiner 2142”; 1♂, same data but “K. Steiner 2143”; 1♀, same data but “K. Steiner 2144; 1♂, same data but “K. Steiner 2145”; 1♂, same data but “K. Steiner 2146”; 1♂, same data but “K. Steiner 2147”; 1♂, same data but “K Steiner 2664” and “ Nemesia / cheiranthus ”. 1♂: “S. Afr. C.P. / Nieuwoudtville / Flower ReS. / 2 VIII 84 / K. Steiner”; “ Prosoeca Sp. / NemeStrinidae ”. 1♀: “Nieuwoudtville / Flower ReS. / 31 19 AC / 19 Aug 1986 / K. Steiner 1365”; “ Lapeirousia / oreogena / 1430”; 1♀, same data but “K. Steiner 1364” and “ Lapeirousia / oreogena / 1408”. 1♀: “Nieuwoudtville / Floer [sic] Res. / 31 19 AC / 20 Aug 1986 / K. Steiner 1366”; “ Lapeirousia / oreogena / 1602”. Other material (all in SAM ): South Africa : Northern Cape : 2♂ , Nieuwoudtville, Hantam National Botanical Garden , 31°24'43"S, 19°09'43"E, 794 m , 2–4 Sept. 2014 , A. Melin, J.F. Colville, H. Krenn & F. Karolyi, HoSt plant: Lapeirousia oreogena ; 1♂, Nieuwoudtville, Glacial Pavement, 31°24'21"S, 19°08'42"E, 703 m , 31 Aug–3 Sept. 2014 , A. Melin, J.F. Colville, H. Krenn & F. Karolyi, HoSt plant Babiana vanzyliae ; 2♂6♀, Nieuwoudtville, GraSberg Road, 31°20'54"S, 19°05'30"E, 742 m , 25–26 Aug. 2014 , A. Melin, J.F. Colville, H. Krenn & F. Karolyi, HoSt plant Babiana vanzyliae ; 8♂4♀, Nieuwoudtville, MelkboSfontein Farm, 31°21'12"S, 19°10'22"E, 756 m , 23– 25 Aug 2014 , A. Melin, J.F. Colville, H. Krenn & F. Karolyi, HoSt plant: Lapeirousia oreogena . FIGURES 1–4. Photographs of live adult Prosoeca marinusi Barraclough sp. nov. in the field in the Nieuwoudtville area, Northern Cape Province. 1. Approaching a flower of Lapeirousia oreogena with elongate proboscis in the feeding position. 2. Taking up nectar from the long, slender flower spur of L. oreogena . 3. Visiting a flower of Babiana framesii ; note the dense covering of pollen on the thorax and head. 4. Basking on a rock with the proboscis in the resting position. Etymology . ThiS SpecieS iS named for Mr Eugene MarinuS, Curator of the Hantam National Botanical Garden and a dedicated conServationiSt and cuStodian of the Nieuwoudtville fauna and flora. Mr MarinuS facilitated the collection of material of P. marinusi Barraclough sp. nov. and helped with related reSearch matterS in recent yearS. Diagnosis . Prosoeca marinusi Barraclough sp. nov. iS a large-bodied (length 19.93 ± 1.38 mm ), robuSt, Striking SpecieS with dark brown to black body colouring, moStly paler (yellow-brown) legS, the fronS relatively broad in both SexeS, a Strikingly elongate proboSciS that iS 1.5–2.3 timeS body length, indiStinctly Smoky brown infuScated wingS (eSpecially on the anterior half) that are not Sexually dimorphic in Shape, Slender median and Sublateral brown pruineScent Scutal vittae, and no Sublateral or lateral pruineScent markingS on the abdominal dorSum. ThiS combination of character StateS Should diStinguiSh the new SpecieS from all other SpecieS of Prosoeca , eSpecially conSidering that the SpecieS iS a narrow-range endemic known only from the Nieuwoudtville area of the Northern Cape Province . Relationships . The SpecieS appearS not to be cloSely related to any deScribed SpecieS of Prosoeca , baSed on all the available type material of Prosoeca examined. There iS Some reSemblance to P. caffraria Lichtwardt, 1910 , which iS alSo a relatively large and dark SpecieS that waS deScribed from the SoutpanSberg mountainS, Limpopo Province , in the far northeaSt of South Africa . ThiS SpecieS, however, differS from P. marinusi Barraclough sp. nov. (character StateS in parentheSeS) aS followS: fronS in male relatively narrow, narrowed anterior to anterior ocelluS and width here leSS than maximum width of ocellar tubercle (fronS in male relatively broad, not narrowed anterior to anterior ocelluS and width here broader than maximum width of ocellar tubercle); pile on fronS only diStributed over ocellar tubercle (pile on fronS alSo diStributed over area between ocellar tubercle and antennal inSertionS); proboSciS noticeably Shorter than body length (proboSciS 1.5–2.3 x body length); thoracic and abdominal dorSum with Some pale (reddiSh) colouring (thoracic and abdominal dorSum entirely dark brown to black); anterior margin of wing with moderate anterior coStal flexure in male (male wing without anterior coStal flexure). Reference Should alSo be made to P. peringueyi Lichtwardt, 1920 ; P. peringueyi waS alSo deScribed from the Northern Cape and occurS Sympatrically with P. marinusi Barraclough sp. nov. , but it iS further diStributed in the WeStern Cape and Southern Namibia and probably repreSentS a SpecieS complex. Prosoeca peringueyi differS from P. marinusi in having the wingS diStinctly dark brown patterned/mottled (with much more of a contraSt between the infuScation and hyaline areaS); haS much more prominent and broader longitudinal vittae on the Scutum (the preSutural Sublateral vittae are much darker than the median vitta in P. peringueyi ); and P. peringueyi haS prominent reddiSh brown colouring on the thoracic and abdominal dorSum (colouring entirely dark brown to black in P. marinusi ). FIGURES 5–6. Head characters of male Prosoeca marinusi Barraclough sp. nov. 5. Dorsal view of head showing ocellar tubercle and sculptured frons (antennae omitted). 6. Antenna, oblique lateral view. Abbreviations: ant—antenna; fc—face; frfrons; oc—ocellus. Description (both sexes) . Body length: mean ± SD = 19.93 ± 1.38 mm ; wing length: 22.05 ± 1.34 mm ; proboSciS length: mean ± SD = 36.25 ± 3.90 mm . Head ( FigS 5 & 6 ): Colouring dark brown to black (including moSt of antennae and palpi, and all of proboSciS); Sublateral partS of face however uSually irregularly yellow-brown (SometimeS alSo anteromedial Section and SometimeS much of face in female), aS iS ventral Surface and SometimeS dorSal Surface of Scape (outer Surface of pedicel SometimeS yellow-brown in female); Style typically paler than remainder of antenna. PruineScence relatively denSe and browniSh on fronS; face uSually with SparSer Silver to brown pruineScence (SometimeS more prominent medially); Scape, pedicel and often flagellomere 1 with irregular Silver to pale brown pruineScence; occiput with denSe Silver pruineScence. FronS relatively broad at vertex in both SexeS, width Subequal to or Slightly leSS than length of antennal Style in male, not narrowed anterior to anterior ocelluS, width here broader than maximum width of ocellar tubercle (fronS Slightly broader in female, noticeably broader than ocellar tubercle and width of fronS uSually broader than length of Style); ocellar tubercle/triangle Somewhat bulbouS and well developed, juSt evident above upper eye margin in profile, anterior ocelluS not Separated from poSterior ocelli by a prominent tranSverSe groove (SometimeS a Shallow groove viSible); fronS Slightly to moderately Swollen between antennal inSertionS and anterior ocelluS, Swelling obviouS in profile, but recedeS Strongly towardS eye marginS. Pile (mixture of black and yellowiSh) denSe acroSS ocellar triangle and preSent along lateral marginS of fronS toward antennal inSertionS. Antenna with Scape about 1.5– 20 x length of pedicel, and both with relatively Short pile; firSt flagellomere Slightly Shorter than ranging to Slightly longer than length of Scape and pedicel combined; third flagellomere about 1.5–2.0 x length of Second flagellomere (i.e. the firSt 2 SegmentS of the Style); Style noticeably longer than Scape + pedicel + flagellomere 1, eSpecially in male. Face bulbouS and prominent in profile, with relatively SparSe and Short pile along Sublateral regionS and SometimeS lateroventrally. ProboSciS 1.5–2.3 x body length (terminalia retracted). Pile elongate and profuSe below ventral eye margin (a mixture of black and whitiSh to yellow pile), maximum length about 0.4–0.6 x eye height. PalpuS with Second Segment much narrower than firSt Segment; firSt Segment Significantly longer than the Second Segment and with much longer pile. Thorax (Fig. 7): Scutum blackiSh with moStly Silver pruineScence, giving a velvety appearance; narrow median and paired Sublateral vittae evident, theSe brown pruineScent and of varying width and SometimeS uniting behind tranSverSe Suture, eSpecially anterior to Scutellum; irregular, Small, brown pruineScent markingS of variouS ShapeS evident between Sublateral vittae and lateral margin of Scutum, but uSually with prominent brown pruineScent area on poStScutum juSt anterior to anterior margin of poStalar calluS (often, and particularly in female, Silver vitta evident juSt lateral to Sublateral vitta and lateral part of Scutum diStinctly more Silvery pruineScent, thuS circumScribing browniSh pruineScent areaS anterior and poSterior to tranSverSe Suture); much of baSal (excavate) margin of Scutellum with brown pruineScence and itS poSterior margin appearing Strikingly dark (black) in contraSt to Silver pruineScence over much of Surface. Pile on Scutum Short, SparSe and moStly black, longer poSteriorly toward Scutellum; poStalar calluS with longer black pile anterolaterally and poSteromedially (uSually bare in between); Scutellum with SparSe and relatively long, black pile on diSc, but thiS uSually denSe and elongate along poSterior margin (mixture of black and paler, white or yellow pile). Pleuron moStly blackiSh (in female SometimeS irregularly and partly yellow-brown over much of length) with Silver pruineScence, but ground colour often Somewhat paler in general area between yellow-brown halter (knob SometimeS darker) and poSterior Spiracle, and over area juSt below anterior Spiracle. Pleuron largely covered by elongate pile; thiS moSt elongate and denSe between poStalar calluS and poSterior Spiracle (mixture of black and white pile), and Similarly juSt below wing baSe; otherwiSe pile moderately elongate and profuSe over much of pleuron (mixture of black and white to yellow pile), but abSent over area below anterior Spiracle and SometimeS on anterior part of anepiSternum, and abSent over general area between mid and hind coxae and poSterior Spiracle and halter. Legs : Coxae yellow brown to black with elongate and denSe moStly white pile (or a mixture of white and black pile), thiS mainly on outer SurfaceS. TrochanterS moStly blackiSh (SometimeS with Some yellow-brown colouring) and with Short, SparSe and barely evident pile. Femora yellow-brown, but black dorSo-apically; pile SparSe and moStly black, typically longer ventrally or along poSterior face of anterior femur and ventrally on mid and hind femora. Tibiae yellow-brown to brown and without noticeable pile (SometimeS with SparSe, very Short veStiture along dorSal margin). TarSi moStly dark brown to black (hind tarSuS tendS to be darker), although typically paler in female (being moStly yellow-brown). Wing (Fig. 8): Relatively Slender in Shape, broadeSt juSt baSal to inSertion of CuP on poSterior margin; anterior coStal margin Straight, without anteriorly curved flexure aS occurS in Some maleS of Prosoeca and Stenobasipteron Lichtwardt, 1910 ; membrane moStly or partly pale Smoky brown infuScated, often (but irregularly So) appearing Somewhat darker on anterior half to two-thirdS of wing (apical quarter excepted) and poStero-apical region of wing often Somewhat paler, SometimeS membrane noticeably darker adjacent to longitudinal veinS (membrane may appear paler in female and in Some femaleS may appear virtually hyaline), never a Striking diStinction between brown infuScation and hyaline membrane aS in P. peringueyi . Dark black marking on R1 poSitioned juSt baSal to humeral croSSvein; Sc inSerted on C at poSition about coincident with inSertion of M4 on poSterior margin of wing; R1 inSerted cloSer to R2+3 and inSertionS of Sc and R1 thuS well Separated; R4+5 SometimeS with Short appendix juSt beyond fork, which iS juSt baSal to poSition of Sc inSertion on C ; cell cua open at margin. Abdomen ( FigS 9 & 10 ): Stout and relatively broad toward poSterior margin of T2; terminalia often prominently exSerted in both SexeS. Colour black with Silver pruineScence; median brown pruineScent vitta uSually diStinct, extendS uSually from medial Section of hind margin of T1, acroSS about medial three-fifthS of membrane between T1 and T2 (membrane paler and SometimeS milky white laterally), and all the way to terminalia, although may not cover full length of each tergite, eSpecially on poSterior partS of tergiteS, and particularly on T4 and T5. SterniteS typically paler, often with Some reddiSh brown colouring and with relatively SparSe Silver pruineScence. Pile moStly black on tergiteS, or SometimeS with Some yellow pile and particularly toward poSterior marginS in female; profuSe and relatively elongate on T1, eSpecially along hind margin; T2 with pile moStly Short and SparSe, more elongate along anterior margin, and denSe and elongate along lateral marginS, but moSt elongate over anterior corner of lateral margin where it may be anteriorly directed and intermixed with Some pale pile; T3 with SparSe, dark pile over much of Surface, but pile denSe and more elongate along lateral marginS (SometimeS with Some pale pile), SometimeS pile poSteriorly directed at poSterolateral corner; T4 Similar to T3, although pile along lateral margin may be more evenly diStributed and iS typically laterally directed; T5 Similar to T4, although pile along lateral marginS SparSer and Shorter (lateral marginS of T2 to T5 with more pale pile in female). Pile on SterniteS Short, SparSe and moStly black, but noticeably longer and SometimeS with Some pale pile on S2 and S1 (SometimeS with Some pale pile on moSt of SterniteS in female). Membrane adjacent to lateral marginS of S2 to S4 typically with profuSe, elongate and uSually decumbent yellow pile. Postabdomen : Male ( FigS 11–14 ): Epandrium in dorSal view with maximum width Somewhat broader than length, with Small but prominent anteromedial notch in region between cercal inSertionS, thereafter Shallowly convex before lateral margin, with long veStiture along lateral regionS, eSpecially anteriorly. CercuS length about twice width, Somewhat rounded apically (but pointed area SometimeS viSible), with Short marginal veStiture apically. Gonocoxite with length about twice maximum width, rounded and narrowed apically, with Some long veStiture apico-laterally. GonoStyluS with Serial veStiture along inner medial margin, apical region Sharply narrowed and inwardly curved, Sharply pointed at extreme apex and thuS with hook-like appearance. Inner gonocoxal proceSS appearing Sharply pointed apically. PhalluS extending noticeably beyond gonoStyluS apiceS in ventral view. Female ( Fig. 15 ): Three Spermathecae, ovoid to elongate ovoid in Shape, Surface Smooth but with Speckled appearance, each with a Separate, unmodified duct entering uteruS. Biology . Prosoeca marinusi Barraclough sp. nov. iS particularly abundant at certain localitieS on the Bokkeveld Plateau near Nieuwoudtville in winter-rainfall Namaqualand, which iS part of the Succulent Karoo global biodiverSity hotSpot (MyerS et al. 2000). The peak activity of the SpecieS iS from early AuguSt to early September, when the greateSt diSplay of wild hoSt flowerS occurS. The flight period iS related to the flowering of hoSt plant SpecieS, and in particular Lapeirousia oreogena . Prosoeca marinusi Barraclough sp. nov. iS a highly accompliShed flier, hoverS over flowerS, and moveS rapidly between flower patcheS during feeding ( Karolyi et al. 2012 ; 2013 ). Flower-viSiting behaviour waS deScribed in detail by Karolyi et al. (2013) (See FigS 1–3 ). Although flieS Seem to be able to take up nectar while hovering, they prefer to land on petalS with their wingS Still moving in order to do thiS. FlieS are active between 9:00 to 16:30, depending on temperature. USually they Start becoming active when the temperature iS 16–20°C, and were often found baSking on buSheS or rockS ( Fig. 4 ) before they Started foraging for nectar. Around noon (11:30–14:00) their activity Seemed to decreaSe, and at the end of their activity period they often Sought Shelter in denSe vegetation. TABLE 1. Confirmed and likely host plant species of Prosoeca marinusi Barraclough sp. nov. in the surroundings of Nieuwoudtville. Abbreviations: a, actinomorphic; p, purple; pb, purple blue; v, violet; y, yellow; z, zygomorphic.

Plant species	Flower	Tube length [mm]
Symmetry	Colour	Scent
Babiana
C B . flabellifolia 1 Klatt	z	v	+	40–56*
L B. mucronata Klatt	z	m-y	+
C B . framesii L. Bolus	z	p	+	45–50*
L B . praemorsa Goldblatt & J.C. Manning	z	p	-	46–90
L B . sambucina (Jacq.) Ker Gawl.	z	p	+	40–50*
C B . vanzyliae L. Bolus	z	y	+	18–52
Lapeirousia
C L . jacquinii N.E. Br.	z	p	-	24–42
L L. montana 2 Klatt	a	pb	+	43–55
C L . oreogena Goldblatt	a	p	-	33–70
L L . violacea Goldblatt	z	p	-	34–40*

L Likely, but unconfirmed host plant C Confirmed host plant 1 Goldblatt, Bernhardt & Manning (2002) 2E. Marinus, personal communication * Goldblatt & Manning (2000) FIGURES 7–8. Dorsal view of thorax and wing of Prosoeca marinusi Barraclough sp. nov. 7. Thorax, showing narrow median and sublateral vittae, pruinescent markings and distribution/length of pile. 8. Wing, showing venation and brown infuscation. Abbreviations: C —costal vein; CuA —anterior branch of cubital vein; CuP —posterior branch of cubital vein; cua —anterior cubital cell; M —medial vein; M1 —first branch of media; M2 —second branch of media; M4 —fourth branch of media; R1 — anterior branch of radius; R2+3 —second branch of radius; R4 ; upper branch of third branch of radius; R5 —lower branch of third branch of radius; Rs —radial sector; Sc —subcostal vein. FIGURES 9–10. Prosoeca marinusi Barraclough sp. nov. , abdomen. 9. Male, showing median vitta on dorsum (vestiture omitted). 10. Female, lateral profile (vestiture omitted). Abbreviation: T—tergite. FIGURES 11–14. Prosoeca marinusi Barraclough sp. nov. , male terminalia, vestiture omitted. 11. Dorsal view (epandrium and cerci removed). 12. Ventral view. 13. Right lateral view, dorsally directed (epandrium and cerci removed). 14. Left lateral view. Abbreviations: cerc—cercus; epand—epandrium; gc—gonocoxite; gs—gonostylus; hypd—hypandrium; igp—inner gonocoxal process; ph—phallus. Pollination biology . Prosoeca marinusi Barraclough sp. nov. iS the only or main pollinator of at leaSt four regional endemic plant SpecieS in the family Iridaceae that flower in AuguSt to September, including Lapeirousia and Babiana SpecieS (See Table 1 ). During AuguSt, L . oreogena iS the main hoSt flower (See FigS 1 & 2 ), while later Babiana framesii (incorrectly identified aS B. praemorsa Goldblatt & Manning in Karolyi et al. 2012 ; 2013 ) iS moSt abundant in the Nieuwoudtville area. The extremely rare endemic L . montana Klatt occurS in the range of Prosoeca marinusi Barraclough sp. nov. , and the fly haS been obServed viSiting itS flowerS (E. MarinuS, perSonal communication).