Amygdalops obtusus, Jindr & Rohác & ek, 2004

Jindr, Rohác, ich & ek, 2004, Revision of the genus Amygdalops Lamb, 1914 (Diptera: Anthomyzidae) of the Afrotropical Region, African Invertebrates 45, pp. 157-221 : 171-176

Amygdalops obtusus sp. n.

( Figs 26–34 , 124 )

Type material: Holotype male labelled: ‘ KENYA, Rt. A 109, Hunter’s Lodge, 30.iv.– 2.v.91, A. Freidberg & Fini Kaplan’ ( TAUI, genit. prep.) . Paratypes: CAMEROON: Rt. N 4, 120 km NW Yaounde, 5.xi.1987, 1 male, A. Freidberg leg. ( TAUI) . GAMBIA: River Tanji 3 km SW Brufut, UTM 28PCK087773, loc. No. 9, at light, 28.ii.1977, 1 female, Cederholm, Danielsson, Larsson, Mireström, Norling, Samuelsson leg. (Lund Univ. Syst. Dept. Sweden Gambia/ Senegal Febr. – March 1977 Expedition, MZLU) . GHANA: Legon , 1.ix.1988, 1 male 4 females, J. den Hollander leg. ( NMWC, SMOC) . KENYA: same data as for holotype, 1 male 1 female ( TAUI, SMOC) ; Tsavo West , Ngulia Lodge, 16–17.viii.1983, 1 male, A. Freidberg leg. ( TAUI) . LIBERIA: Suakoko , 3.v.1952, 1 male, C. C. Blickenstaff leg. ( USNM) . NIGERIA: Ibadan , lush vegetation by river, 16–19.i.1966, 1 male, J. C. Deeming leg. ( USNM) . SOUTH AFRICA: Natal , 10 km NE Drummond, 18.ix.1983, 1 male, A. Freidberg leg. ( TAUI) ; Natal , Pietermaritzburg, Scottsville, malaise trap, 8–14.iv., 1 male, 15–21.iv., 1 male 1 female, 22–30.iv., 1 male, 13–19.v., 1 female, 20–26.v., 1 male, 27.v.–2.vi.1986, 1 female, R. M. Miller leg. ( NMSA, SMOC) ; Natal , Ukulinga Res. Frm., 10 km SE Pietermaritzburg, grassland, malaise trap, 7–13.iii.1986, 1 female, R. M. Miller leg. ; Natal , 6 miles S of Pongola, 6.vi.1967, 1 male 2 females, Natal South Africa Govn. Ent. leg. (all NMSA) ; TANZANIA: Ngorongoro Res. Gate , 1500 m, 6.ix.1992, 1 male, A. Freidberg leg. ( TAUI) ; UGANDA: S.W., Kabale-Ketuna Rd. , 1900 m, 23.xii.1995, 2 females, I. Yarom & A. Freidberg leg. ( TAUI) ; ZAIRE (REPUBLIC CONGO): Parc National Albert , Mont Hoyo, 1 280 m, sur plantes basses, 7–15.vii.1955, 1 female, P. Vanschuytbroeck leg. ( MRAC) . Almost all paratypes with genit. prep .

Etymology: The specific name ‘obtusus’ (= Lat. obtuse, blunt) is derived from the short and blunt male gonostylus.

Description: Male.

Externally closely resembling A. thomasseti , including colour. Total body length 1.90– 2.38 mm.

Head: Slightly to distinctly longer than high. Frons narrow as in A. thomasseti ; occiput brown with somewhat paler postocular stripes or also adjacent areas. Frontal structures similarly shaped, coloured and microtomentose as in A. thomasseti but usually darker (as in dark form of the latter species). However, there are also lightly coloured specimens resembling in this respect typical form of A. thomasseti . Gena darker, yellow and less densely microtomentose. Cephalic chaetotaxy similar to that of A. thomasseti : pvt short with apices medially meeting or crossed; vti long, slightly to distinctly shorter than vte (vte longest of cephalic setae); oc usually shorter and thinner than vti; 2 strong ors (anterior usually shorter, posterior often almost as long as vte) and 2 microsetulae in front of anterior ors (the anterior microsetula only half length or less of posterior); microsetulae (1–2 pairs) medially in anterior third of frons very minute and often indistinct; 1 long vi and 1 subvibrissa (distinctly shorter than vi). Palpus as in A. thomasseti . Longest eye diameter about 1.5–1.6 times as long as shortest; gena very low (narrow) anteriorly, with its smallest height only 0.07 times as long as shortest eye diameter. Antenna as in A. thomasseti , with darker (brownish ochreous) pedicel and vicinity of arista.Arista about 2.2 times as long as antenna, very long pectinate, mainly dorsally.

Thorax: Similarly coloured as in A. thomasseti , including a pair of orange ochreous stripes covering dorsocentral lines, sometimes extending to posterior dc and often anteriorly dilated and almost meeting medially and laterally connected with humeralnotopleural yellow band. Thoracic chaetotaxy: 1 very small prs; 2 dc, anterior short and weak, posterior as long as apical sc; 2 sc, apical very long, basal weak, about as long as anterior dc; ppl indistinct or absent; 2 stpl, anterior markedly shorter, as long as fine setae on ventral part of sternopleuron. Scutellum as in A. thomasseti , slightly convex. Legs yellow to pale ochreous, with same chaetotaxy as in A. thomasseti . Wing pattern agreeing perfectly with that of A. thomasseti and venation also very similar. Wing measurements: length 1.90–2.38 mm; width 0.57–0.73 mm, Cs 3: Cs 4 = 2.14–3.06, r-m\dm-cu: dm-cu = 2.67–3.28. Haltere yellow, knob often paler.

Abdomen: T1 and T2 brown, but with small pale lateral spot lying on boundary of T1 and T2 (in very light specimens more extended to basal half of T2). T2–T5 normally uniformly brown, rarely T5 with small, pale pigmented laterobasal spot on each side. Preabdominal sterna all pale yellow to ochreous, becoming broader posteriorly, S5 the widest. Postabdominal sterna (S6–S8) very similarly formed as in A. thomasseti .

Genitalia: Epandrium ( Figs 26, 29 ) small, sparsely setose, with pair of longer setae dorsomedially. Cercus smaller than in A. thomasseti . Medandrium ( Fig. 29 ) relatively low and pale. Gonostylus ( Figs 27, 28 ) short and broad, rounded subquadrate, apically blunt and with small tubercles, outer surface of gonostylus without macrosetae but with dense micropubescence covering its posterior two-thirds; inner surface ( Fig. 28 ) with numerous setae in its anteroventral half. Hypandrium ( Fig. 26 ) similar to A. thomasseti , with membranous internal lobes; transandrium also similar but more strongly bent dorsomedially and both sclerites representing divided caudal process more curved laterally in distal third. Pregonite ( Fig. 26 ) fused with hypandrium but somewhat separated posteriorly by narrow notch, with 5–6 setae. Postgonite ( Fig. 26 ) slender, slightly bent, apically tapered but not acute and bearing 1 anterolateral seta in its middle; basal sclerite attached to postgonite darker pigmented and ventrally dilated in contrast to that of A. thomasseti .Aedeagal part of folding apparatus at base of phallapodeme ( Fig. 26 , afa) armed by tuberculiform spines and elongate ribs; connecting sclerite ( Fig. 26 , cs) partly brownish, relatively broad. Basal membrane similarly sculptured as in A. thomasseti , with transversely formed and arranged tuberculiform spines. Aedeagal complex ( Fig. 26 ) with phallapodeme having bifurcate base. Aedeagus with short frame-like phallophore and large distiphallus. Saccus of distiphallus voluminous (particularly in erect position), armed by dense short thick spines in apical half and by fine short setulae in basal half ( Fig. 26 ). Filum of distiphallus formed by 2 stripe-like twisted sclerites and its apex largely membranous. Ejacapodeme small, with slender projection.

Female. Differs from male as follows:

Total body length 2.06–2.50 mm.

Occiput usually paler than in male, sometimes largely yellowish except for medial brownish ochreous part. Longitudinal orange stripes on mesonotum usually short, reaching to suture, only in pale specimens longer. f 3 posteroventrally simply setulose, without short thickened setae. Wing measurements: length 1.98–2.78 mm, width 0.61– 0.85 mm, Cs 3: Cs 4 = 2.00–3.21, r-m\dm-cu: dm-cu = 2.36–3.50. Abdomen with preabdominal terga uniformly brown (as in dark form of A. thomasseti ), with a pale lateral spot (variable in size) on each side of boundary area between T1 and T2. Preabdominal sterna (S1–S5) pale yellowish ochreous, becoming wider posteriorly.

Postabdomen ( Figs 30, 33 ). T6 markedly broader than T7, tapered posteriorly, dark brown, at most its anterior margin pale ochreous. T6 and T7 with dense, short but thick setae. S6 wider than S5, pale yellow but always with distinctly brownish darkened band (maximally covering one-third of sclerite) at posterior margin. T7 narrow, with shallow anterior emargination, dark brown. S7 with simple dark pigmentation in anterior three-fourths, unpigmented microtomentose posterior fourth and only few thin setae in posterior half. T8 dark, plate-shaped, longer and with more setae than in A. thomasseti , with straight anterior margin and more or less rounded posterior one. S8 also dark, very similar to that of A. thomasseti . T10 small, relatively narrow and distinctly longer (less transverse) than in A. thomasseti , pale pigmented posteriorly and with a pair of longer setae. S10 similar to that of A. thomasseti but anteriorly more rounded and covered by distinctive micropubescence. Internal sclerotisation of genital chamber composed of posterior well developed and pale brown sclerites (see Fig. 32 ) and anterior unpigmented ring-shaped structure of very indefinite, somewhat transversely twisted shape. Ventral receptacle ( Fig. 34 ) very similar to that of A. thomasseti , with apical projection less strongly curved ventrally. Spermathecae 1+1 ( Fig. 31 ) ball-shaped, one spermatheca distinctly larger than the other, each with short blunt spines as in A. thomasseti , but with shorter cervix. Cerci as in A. thomasseti .

Discussion: A. obtusus sp.n. is extremely similar to A. thomasseti in external features. Because of great colour variability of both species (and of A. thomasseti in particular) this new species cannot be reliably separated from A. thomasseti unless male or female genitalia are examined. However, the genital structures are distinctive so that A. obtusus sp.n. can safely be recognised from among all congeners by the short blunt gonostylus of the male or the shape and pigmentation of S7 and T10 of the female. Other specific characters of A. obtusus sp.n. are: saccus with very short and dense spinulae and setulae, apex of filum of distiphallus membranous but dilated, posterior internal sclerites of female genital chamber compact, and ring-shaped structure reduced.

Biology:Adult flies were collected in all months except for October. A few data refer to specimens swept from grassland vegetation or lush vegetation by rivers. Some specimens were caught by means of Malaise traps in grassland.

Distribution: The species seems to be widespread throughout tropical Africa. There are records from Liberia, Gambia, Ghana, Nigeria, Cameroon, Zaire (Republic Congo), Kenya, Uganda, Tanzania and South Africa.

Figures

Figs 26–29. Amygdalops obtusus sp.n., male paratype (Kenya). 26. Genitalia, erect position, lateral view. 27. Gonostylus, outer side, sublateral view (widest extension). 28. Same, inner side. 29. External genitalia, caudal view. Scales: Figs 27–28 = 0.05 mm, others = 0.1 mm. For abbreviations see text.

Figs 30–34. Amygdalops obtusus sp.n., female paratype (Kenya). 30. Postabdomen, dorsal view. 31. Spermathecae. 32. Internal sclerites, ventral view. 33. Postabdomen, ventral view. 34. Ventral receptacle, lateral view. Scales: Figs 30, 33 = 0.1 mm, others = 0.05 mm.

Figs 122–125. Wings of Amygdalops species. 122. A. trivittatus Frey, female holotype. 123. A. thomasseti Lamb, male (Uganda). 124. A. obtusus sp.n., male paratype (Kenya). 125. A. simplicior sp.n., male paratype (Nigeria). Scales = 0.5 mm.