Anthomyia stuckenbergi, Ackland, 2001

Ackland, D. M., 2001, Revision of afrotropical Anthomyia Meigen, 1803 (Diptera: Anthomyiidae), with descriptions of ten new species, African Invertebrates 42, pp. 1-94 : 51-54

Anthomyia stuckenbergi sp. n.

( Figs 94 , 114–122 )

Holotype Ò: SOUTH AFRICA: KwaZulu-Natal: ‘Royal Natal / National Park / Drakensberg Mts./ B. & P. Stuckenberg’; ‘from montane forest / 12.ix.63 / 1500 m.’ ‘ HOLOTYPE Ò / Anthomyia / stuckenbergi / Ackland’ [Rectangular red printed and written label] ‘Holotype’ [circular white label with red perimeter]. In good condition. Genitalia dissected and mounted in balsam on a plastic slip on the pin (NMSA).

Paratypes: SOUTH AFRICA: KwaZulu-Natal: 4Ò3^, Royal Natal National Park, Drakensberg Mts. , 16.ix.1963, 1530 m, B. & P.Stuckenberg, from montane forest ( NMSA) ; 1^, same locality but 2282DB, 28–29.iv.1984, J. Londt, forest margins & grasslands ( NMSA) ; 1Ò, Giant’s Castle Res., Drakensberg , 18–23.ix.1961, 5800 ft, B. &P.Stuckenberg ( NMSA) ; 1Ò, same locality, ii.1970 [no further data] ( NMSA) ; 1Ò, Town Bush , 28.vii.1981, R. Elfenink [no further data, presumably Pietermaritzburg] ( NMSA) ; 1Ò, Ulundi , ix.1896, 5000–6000 ft, G. A. K. Marshall ( BMNH) . Western Cape: 3Ò, 12 km SW Clanwilliam Kransvlei R., 3218BB, 5.x.1977, R. M. Miller ( NMSA) .

Etymology: This species is named in honour of Dr Brian Stuckenberg, the distinguished Dipterist and collector of so much valuable African material.

Male:

Colour: Interfrontalia, parafrontalia and genae varying from dark brown to blackish (with rather dense silvery dusting); parafrontals opposite lunule with a shifting brownish sheen stripe which extends from lunule to level of arista, and a brownish non-shifting spot in vibrissal angle which extends between genal groove and eye margin (in some examples not quite reaching eye margin) when viewed in profile; face and occiput blackish (with normal dusting), except upper part of occiput rather shining blackish. Antennae dark brown. Palpi dark brown to black; arista brownish but paler in basal half; prementum dark brown, very thinly dusted and rather shining. Thorax ( Figs 114, 115 ) densely dusted (over dark ground-colour) with contrasting black and silvery grey pattern on dorsal surface, when viewed from in front the silvery dusting is rather shifting and becomes greyer; transverse postsutural band across the scutum complete between wing bases, anterior margin very slightly, posterior margin distinctly sinuate, the posterior median projection reaching level of posterior dorsocentral seta; presutural spots large, separated behind head, each spot filling the space between presutural dorsocentrals and posthumeral setae and continuing anteriorly to front margin of thorax (inner margins more or less parallel); scutellum largely black, with only its tip silvery grey. Pleura largely grey dusted, lower part of the post pronotal lobes, anterior corner of anepisternum and anterior part of anepimeron darkened. Abdomen largely densely dusted over dark ground-colour, with contrasting black and grey pattern on tergites, except 1st and 2nd tergites expanded anteriorly on each tergite in to a black band which is not quite half length of tergite, and which is two-thirds length of tergites laterally; sternites orange-brown; pregenital sclerite contrastingly shining blackish (undusted); hypopygium and 5th sternite rather finely dusted. Wing membrane and veins pale brownish tinged; wing bases with whitish membrane and white root vein; squamae white with whitish fringes;

halteres yellow. Legs dark brown to blackish (except for the partly shining orange trochanters and orange-brown bases to femora).

Head: Parafrontalia very narrow posteriorly, touching or almost touching for one-third of frons length (frontal stripe obsolescent here), widening anteriorly to slightly less than width of first flagellomere; eyes separated by width of anterior ocellus; genae below lowest point of eye margin 0.26–0.28 times eye-height. 2 pairs of parafrontal setae on anterior half of distance between antennal base and anterior ocellus; very fine short hair-like interfrontal setulae present or absent at middle of frons. First flagellomere twice as long as wide (apex not quite reaching lower facial margin); arista tapering from base to apex (not abruptly narrowing in distal two-thirds), nearly twice length of first flagellomere, short pubescent, longest hairs not as long as diameter of base. Prementum about 0.4 times as long as head height.

Thorax: 3 pairs of relatively strong presutural acrostichals (the middle the longest) and about three-quarters length of anterior presutural dorsocentral setae, in rows separated by about distance from each to adjacent dorsocentral row, without additional setulae in between; acr / dc ratio 1:1:1; 1 + 1 posthumerals; prealar of same length or slightly longer than posterior notopleural; dorsal surface of scutellum bare centrally, setulose towards sides; katepisternals (2)1 + 2(3), lower posterior nearly as long as upper posterior seta; anepisternum with a distinct upper anterior setula

Legs: f2 with row of 6–7 pv on about basal half, 0 av; f3 with 8 av in distal three-quarters, no developed pv; t1 with median 1 pv; t2 with 1 very short ad, 1–2 pd and 2 p/ pv; t3 with 1 av, 6 ad, 2 pd and 3–4 pv.

Wing: costa with all marginal spinules short; the pair before distal break not differentiated; lower crossvein sinuate, joining M 1+2 obliquely; last section of M 1+2 1.3 times length of preceding section. Lower squama as long as upper.

Wing length up to 6.8 mm.

Abdomen: 4th sternite ( Fig. 118 ) about 1.5–2 times as long as wide, more or less parallel-sided with a straight posterior margin which is densely clothed with long setae laterally and posteriorly. 5th sternite processes ( Fig. 118 ) short, with 3–5 short setae laterally at their bases, otherwise with multiserial rows of long setulae on their concave inner margins, their tips touching on mid line; membranous lobes ( Fig. 119 ) subapical, projecting ventrally in lateral view, apically rounded, the apical setulae very long as are the inner basal setulae in profile. Central process of synsternite (6+7) (Fig. 112) with long divergent arms, their tips becoming parallel. Surstylus ( Figs 116, 117 ) slender, only weakly downcurved, in dorsal view very characteristic and differing from all other afrotropical Anthomyia species (inner lobe produced and bearing 2 slender spinules, separated from the outer lobe by a deep incision). Cercal plate ( Fig. 116 ) of about equal length and width, with rather long and slender apical spinules and 1–2 pairs of longer setulae on either side of them, otherwise weakly setulose only on basal half, in profile apex not at all projecting, rounded and concealed behind surstylus. Pregonite ( Fig. 120 ) parallel-sided with 2 setulae on distal margin; postgonite ( Fig. 120 ) with an narrow setula (arising on inner surface some distance from the obtuse ventroapical corner. Distal section of aedeagus ( Fig. 121 ) with a robust distally directed dorsal process only slightly separated from its base; its apex abruptly bent, dorsal margin of distal section straight in basal half in lateral view, with apical part abruptly bent upwards.

Female:

Colour: Head dark as in male, palpi sometimes orange basally. Thoracic pattern very similar to that of male, sometimes with base of scutellum narrowly grey dusted.Abdomen with black and grey pattern on abdominal tergites similar to that of male. Legs dark as in male (femora sometimes orange-brown in basal half).

Head: Eyes widely separated (by about their transverse width, ratio 10:9:10); interfrontalia at level of middle orbital setae about four times as wide as each parafrontal; parafrontalia widening anteriorly to about width of first flagellomere; genae below lowest point of eye margin about 0.3 times eye-height. Arista tapering as in male. Parafrontal setae differentiated into 3 pairs of orbital setae (anterior setae normally proclinate, posterior two reclinate) and one pair of (inwardly directed) frontal setae; crossed interfrontal setae well developed, as long and strong as adjacent orbital setae. Thorax: Presutural acrostichal setulae as in male. Katepisternals 1(2) + 1 (the hair-like anterior ventral setula longer than the fine hair below the posterior setula.

Legs: f2 with 2–3 pv on basal half; f3 with 3–4 short av, without pv; t1 with 1 ad, 1 p; t2 as in Ò, but ad stronger; t3 with 1 av, 5 ad and 2 pd.

Wing length up to 6.5 mm.

Abdomen: Postabdomen ( Fig. 94 ) equal in length to preabdomen. Tergites 6–8 more or less continuously sclerotised across the dorsum posteriorly (where they bear rows of setulae), divided anteriorly into pairs of dorsolateral strips (those on 8th tergite long and narrow, and closer together anteriorly), with a trace of a central strip. 6th and 7th sternites long and narrow, each bearing a few setulae posteriorly (one pair rather long); 8th sternite divided into a pair of elongate strips of sclerotisation, posteriorly with only a pair of long setae. 10th tergite almost as long as wide, bearing about 4 setulae posteriorly; 10th sternite as long as wide, with 4 longer setae on posterior margin; cerci rather short (only as long as 10th tergite) and inwardly directed, with only short setulae. Spermathecae 3, ribbed, longer than wide (0.13 x 0.07 mm).

Discussion: A. stuckenbergi can be distinguished from all other African Anthomyia species by the cercal plate in lateral view being apically entirely convex, with no upturned or projecting apex. It is closely related to A. whitei through the shape of the synsternite (6+7) process, the seta on the postgonite arising from the inner surface, the large ventrally directed membranous lobes on the 5th sternite processes (in lateral view), the long basal setae on the inner margins of the processes of the 5th sternite, and the strong distally directed subbasal dorsal process on the distal section of the aedeagus.

The species may have been overlooked, however, as the general appearance of the fly is not so very different from many other Anthomyia species; the undulate posterior margin of the postsutural crossband being similar to species in the pluvialis superspecies (those with complete postsutural crossbands)., and abyssinica . The latter has plumose arista and a strong costal spine, the former has the dark spot on the vibrissal angle not reaching eye margin.

Distribution: Only known from South Africa (Western Cape and KwaZulu-Natal).

Figures

Figs 92–94. ^ apical segments of ovipositors. 92. Anthomyia maculigena Stein (Angola). 93. Anthomyia whitei sp. n. (paratype, Ethiopia). 94. Anthomyia stuckenbergi (paratype, KwaZulu-Natal, South Africa).

Figs 114–122. Anthomyia stuckenbergi sp. n. Ò (paratype, KwaZulu-Natal). 114. Thorax, dorsal view. 115. Ditto, lateral view. 116–122. Ò terminalia. 116. Cercal plate and surstyli, caudal view. 117. Ditto, lateral view. 118. 4th and 5th sternites, ventral view. 119. 5th sternite, lateral view.120. Gonites. 121. Distal section of aedeagus. 122. Central process of synsternite (6+7).