Anthomyia concava, 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 : 88-92

Anthomyia concava sp. n.

( Figs 220–226 )

‘ Anthomyia griseobasis Malloch. ’ Emden, 1951: 352 (in part).

Holotype Ò: UGANDA: ‘ Holotype’ [white circular printed label with red perimeter]; ‘ UGANDA: / Ruwenzori Range / xii.1934 – i.1935 / B. M. E.Afr.Exp. ’ [white rectangular printed label]; ‘ Namwamba Valley / 6500ft / F. W. Edwards’ [white rectangular printed label] ; ‘ HOLOTYPE Ò / Anthomyia concava / D. M. Ackland’ [red rectangular printed and written label]. In reasonable condition, right wing missing. Genitalia dissected and mounted in glycerol in a plastic tube on staging pin. In BMNH.

Paratypes: KENYA: 1^, Aberdare Range , Katamayo, x.1934, 8000 ft, F. W. Edwards, B. M. E. Afr. Exp. ( BMNH) ; 1^, W Ruwenzori, 8–9000 ft, vii.1945, van Someren, (det. Anthomyia griseobasis Mall. , by van Emden, 1945) ( BMNH) ; 1^, Nairobi , vii.1930, van Someren ( BMNH) .

Other material examined: KENYA: 1^, Teita Hills , (S), viii.1947, van Someren, (det. Anthomyia benguellae Mall. by van Emden, 1947 ( BMNH).

Etymology: L. concavus = hollow. Refers to the concave sides to the cercal plate in the male.

Male:

Colour: Interfrontalia, parafrontalia and genae varying from dark brown to blackish (with rather dense silvery dusting); parafrontals opposite lunule with a rather indistinct darker shifting sheen stripe which extends from lunule to level of arista, and a greyish brown non-shifting spot in vibrissal angle which extends above genal groove and reaches eye margin when viewed in profile; face and occiput brown (with normal dusting), except upper part of occiput slightly shining blackish. Antennae brown, pedicel orange distally. Palpi brownish orange; arista orange; prementum dark brown, rather shining. Thorax ( Fig. 219 ) dusted greyish in parts (over orange ground-colour), presutural areas largely orange-brown and semi-shining, contrasting with grey dusting along suture, between presutural acrostichals and on post pronotal lobes; pleura with thin orange shifting grey dust over translucent orange ground colour; transverse postsutural band across the scutum semi-shining brownish orange, reaching midway between the 2nd and 3rd postsutural dorsocentral setae; complete between wing bases (posterior margin weakly indented); presutural spots large and ill defined, joined anteriorly; scutellum brown, with posterior half grey dusted. Abdomen largely densely dusted over dark ground-colour. Wing membrane weakly greyish; stem vein whitish in contrast to dark basicosta and the veins beyond humeral crossvein, which are brownish; halteres yellow. Legs dark brown (except for the partly shining trochanters which are orange).

Head: Parafrontalia very narrow posteriorly (touching in upper frons half), widening anteriorly to half width of first flagellomere; eyes separated by half width of anterior ocellus; genae below lowest point of eye margin 0.2–0.23 times eye-height. 2 pairs of parafrontal setae on anterior half of distance between antennal base and anterior ocellus; short interfrontal setulae present; genal setae in more or less single row anteriorly. First flagellomere slightly more than twice as long as wide (apex not quite reaching lower facial margin); arista slightly swollen basally, nearly twice length of first flagellomere, short plumose, longest hairs about one-third width of 1st flagellomere (total width of hairing about two-thirds of that width). Prementum about 0.4 times as long as head height.

Thorax: 3 pairs of strong presutural acrostichals (the middle the longest) in rows separated by about distance from each to adjacent dorsocentral row, without additional setulae in between; acr / dc ratio 1:1:1 or 9:10:9; posthumerals1 + 1; prealar nearly twice as long as posterior notopleural seta (which is however only half length of anterior notopleural seta); only 2–3 fine proepisternal hairs, dorsal surface of scutellum bare centrally between strong setae, only 1–2 setulae laterally above the marginal row; katepisternals 2 + 2, lower posterior nearly as long as upper anterior seta, lower anterior seta two-thirds length of upper; anepisternum with a developed upper anterior setula.

Legs: f2 with row of 5–6 pv on about basal half; f3 with 4–6 av in distal half; t1 with median 1 pv; t2 with 1 very short ad, 1–2 pd and 2 p/pv; t3 with 1 av, 2–3 ad, 2 pd and 2–3 pv. Pulvilli enlarged, those of fore legs nearly as long as 5th tarsal segment.

Wing: costa with all marginal spinules short; the pair before distal break distinct but short, hardly differentiated; lower cross-vein slightly sinuate, joining M 1+2 obliquely; last section of M 1+2 1.87 times length of preceding section. Lower squama small, shorter than upper, and concealed by it.

Wing length 6.5 mm.

Abdomen: More than twice as long as wide (2.6), dorsoventrally flattened in basal two-thirds, more or less parallel-sided from 2nd to 4th tergite. 3rd sternite long and narrow, twice as long as wide; 4th sternite ( Fig. 222 ) twice as long as wide, with a straight posterior margin, and 3–4 long lateral setae; 5th sternite processes ( Figs 222, 223 ) (which are short and rather widely separated) with a few short setae laterally at their bases, otherwise with long biserial rows of setulae on their concave inner margins (median setae as long as the others); membranous lobes ( Fig. 223 ) small and not visible in lateral view. Central process of synsternite (6+7) ( Fig. 226 ) consisting of a single sharp pointed process. Surstylus ( Fig. 221 ) hardly downcurved, appearing constricted medially in lateral view, bearing a ventral row of setulae and 2 short spinules below the angle of its inner lobe; in profile upper dorsal margin with a small but well-defined lobe, ventral margin sinuate. Cercal plate ( Fig. 220 ) of about equal length and width, in apical third constricted, the margins being distinctly concave, with a few short apical spinules and one pair of quite long setulae on either side of them, otherwise setulose only on basal half, in profile apex strongly projecting, with dorsal surface almost straight. Pregonite ( Fig. 224 ) very small (less than half length of postgonite) slightly constricted medially, with 2 setulae on oblique distal margin; postgonite ( Fig. 224 ) with a very small unexpanded setula (on ventroapical margin), the dorsal projection strongly excavated on ventral margin, and the dorsal and ventral margins almost parallel. Distal section of aedeagus ( Fig. 225 ) rather long and slender and hardly widened in distal half in profile, with a more or less upright dorsal process separated from its base by much less than its length.

Female:

Colour: similar to male. parafrontals opposite lunule with an orange-brown shifting sheen stripe, and another orange-brown spot in vibrissal angle which extends above genal groove and almost reaches eye margin; antennae dark brown, only indistinctly orange in places. Thorax with transverse postsutural band similar to male, only slightly shining orange and contrasting with the grey dusted ground colour; presutural spots also orange (it is unclear whether these orange spots are the normal condition in both males and females, but all the type material agree in this); scutellum brown with only the tip grey dusted.

Head: Eyes widely separated (by slightly more than their transverse width, ratio 5:6:5), interfrontalia at level of middle orbitals about 3 times as wide as each parafrontal; frontal stripe with convex margins. 3 pairs of orbitals and 1 pair of inclinate frontal setae.

Thorax: as male, except the presutural acrostichal setae have a few fine hairs between rows; Two of the three paratypes are lacking the usual fine setulae or hairs on both sides of the proepisternum (propleural depression), the other paratype (Ruwenzori) has 2–3 hairs on each side.

Legs: t1 with 1 ad and 1 pv setae (at about same level); t2 with a stronger ad seta; t3 with 1 av, 4–5 ad, 2 pd and 2–3 pv.

Abdomen: ovipositor about as long as abdomen; similar to maculigena .

Wing length 6.5 mm.

Discussion: The holotype of concava was listed under griseobasis by Emden (1951: 352), and found in the BMNH standing over this name. The female from the Aberdare Range, Katamayo, in the same paper is, I believe, a female of concava . Another female (W Ruwenzori, van Someren), identified by Emden as griseobasis , is also concava . The female from the Teita Hills was identified by Emden as benguellae ; it is in poor condition, but may be concava .

The general appearance of the holotype male of concava (with a largely orange-brown, rather translucent ground colour, and the usual black pattern represented by semi-shining orange-brown postsutural crossband) suggest it is an immature specimen. The genitalia are, however very distinctive. The concave lateral margins of the cercal plate, short surstyli, very small pregonite in relation to the postgonite, the absence of any membranous lobe on the processes of the 5th sternite, and above all, the single sharply pointed process on the synsternite (6+7) are worthy of mention. It is possible that the thorax pattern in any future material will exhibit a more typical black and grey pattern.

All three female paratypes have more or less the same orange-brown coloration as the holotype.

Distribution: Only known from the mountains of Kenya and Uganda.

Figures

Figs 219–226. Anthomyia concava sp. n. holotype Ò. 219. Thorax, dorsal view. 220–226. Terminalia. 220. Cercal plate and surstyli, caudal view. 221. Ditto, lateral view. 222. 4th and 5th sternites, ventral view. 223. 5th sternite, lateral view. 224. Gonites. 225. Distal section of aedeagus. 226. Central process of synsternite (6+7).