Amygdalops obscurior, 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 : 194-198

Amygdalops obscurior sp. n.

( Figs 77–86 , 129 )

Type material: Holotype male, labelled: ‘ UGANDA: S.W., Semiliki Forest , 1250 m, 8.i.1996, 1 male, I. Yarom & A. Freidberg’ leg. ( TAUI, genit. intact) . Paratypes: UGANDA: same data as for holotype, 4 males 6 females ( TAUI, 1 male 1 female SMOC, all with genit. prep.) .

Etymology: The species is named ‘obscurior’ (= Lat. darker) owing to its darker colouring of frons, thorax, halteres etc.

Description: Male. Total body length 1.78–2.10 mm; bicolorous, dark brown and yellow. Head: Slightly higher than long. Occiput completely dark brown. Frons dark brown, only its anterior fourth ochreous to yellow (at frons margin). Frontal triangle very narrow, bare and shiny including ocellar triangle and reaching over anterior third of frons. Orbit dark brown, with only anterior fourth ochreous or yellow, shiny throughout its length and almost without microtomentum; stripes between orbits and frontal triangle dark grey microtomentose and dull. Face yellowish to brownish ochreous; narrow parafacialia, gena and ventral part of postgena whitish yellow, silvery white microtomentose. Ventral margin of gena, outer mouthparts and palpus pale brown; inner mouthparts (proboscis) yellow. Cephalic chaetotaxy: pvt short, with apices crossed; vte and posterior ors subequal and longest among cephalic setae; vti and oc subequal and about two-thirds of vte; 2 long ors, anterior only slightly shorter than posterior) and 2 usual ors setulae (anterior very minute) in front of anterior ors; 1–2 pairs of microsetulae medially in front of frontal triangle; 1 long vi and 1 shorter subvibrissa (about two-thirds of vi); peristomal setulae short and postoculars yet smaller; palpus with distinct subapical seta. Eye with longest diameter 1.4 times as long as shortest one. Gena very narrow; its smallest height 0.08 times as long as shortest eye diameter. Antenna yellow, with darkened apical part of inner side of pedicel and vicinity at insertion of arista. Arista 1.9 times as long as antenna, long pectinate, particularly dorsally proximally.

Thorax: Markedly narrower than head, bicolorous. Mesonotum including scutellum and notopleural areas brown to dark brown; also humeral callus, entire propleura and dorsal band across pleura brown; ventral part of pleura yellow to pale yellow. Thoracic chaetotaxy: 1 small prs; 2 dc, posterior very long and as long as apical sc, anterior small, only one-fourth posterior; 2 sc, apical long, laterobasal about as long as anterior dc; 1 ppl, reduced to microsetula; 2 stpl, posterior strong and longer than usual, anterior short and weak; other setae on ventral part of sternopleuron few and hair-like. Scutellum rounded triangular, more convex dorsally. Legs yellow to yellowish ochreous, only f 3 with brown darkened apical fourth. Chaetotaxy of legs as in A. thomasseti ; f 3 with usual posteroventral row of setae which are strongly shortened and densely arranged in apical

Fig. 87. Amygdalops acer sp.n., male holotype. Hypandrium and associated structures, lateral view. Scales: Figs 82–84 = 0.05 mm, others = 0.1 mm.

fourth. Wing ( Fig. 129 ) with 2 whitish iridescent spots, larger one between R 4+5 and C in front of subapical dark area, and smaller rounded one behind posterior (dm-cu) crossvein and large subapical dark spot. R 2+3 and R 4+5 distinctly, M slightly sinuous. Discal (dm) cell relatively long, with r-m situated in front of its middle. A 1 very short, anal lobe strongly reduced. Wing measurements: length 1.98–2.18 mm; width 0.61–0.66 mm, Cs 3: Cs 4 = 2.21–2.58, r-m\dm-cu: dm-cu = 2.87–3.58. Haltere with yellow stem and dark to blackish brown knob.

Abdomen:All preabdominal terga and sterna brown to dark brown. T6 small, transverse, weakly sclerotised and very pale brown. Preabdominal sterna becoming wider posteriorly, S5 markedly broader than preceding sclerites, with shallow posterior emargination. Postabdominal sterna S6–S8 dorsolaterally fused, heavily sclerotised and dark brown. S6 ventrally projecting in a narrow transverse stripe reaching far on right side of abdomen.

Genitalia: Epandrium hemispherical, medium-long ( Figs 77, 78 ), moderately setose; 1 dorsomedial, 1 lateral and 2 posterior ventrolateral setae longer than others; anal opening small, rounded substriangular ( Fig. 77 ). Cercus relatively short, finely setose.Medandrium ( Fig. 77 ) comparatively wide and low. Gonostylus ( Fig. 80 ) medium-sized, broad basally and tapered apically, with blunt apex, micropubescence restricted to distal third of outer side; inner side of gonostylus with longer setae, particularly at anterior margin.Hypandrium ( Fig. 79 ) relatively robust, heavily sclerotised including posterolateral bulging part, with large membranous internal lobes; transandrium slender, medially bent dorsally; caudal process formed by a pair of slender sclerites arising close to each other in medial concavity of transandrium, divergent and widened distally. Pregonite ( Fig. 79 ) very low, fused with hypandrium, incurved, not projecting ventrally, with 5–6 setae, 1–2 of them shorter. Postgonite ( Fig. 79 ) slightly sinuous, slender in lateral view but actually flat, broad in ventral view, with 1 proximal seta inserted on ventrolateral surface; basal sclerite attached to postgonite large, dark but incurved and hence slender in lateral view. Aedeagal part of folding apparatus attached to base of phallapodeme ( Fig. 81 ), dark dorsally and provided by relatively small flat tubercle-like spines; connecting sclerite slender, pale pigmented. Basal membrane ( Fig. 79 ) covered by transverse hyaline tubercles (ventrally) and short spines (dorsally). Aedeagal complex ( Fig. 81 ) with moderate phallapodeme, having usual bifurcate base and simple apex. Aedeagus with small (as long as high) phallophore and voluminous distiphallus. Base of distiphallus finely setulose. Saccus of distiphallus large, except for base membranous and with two groups of fine spines, less dense in basal half and denser in apical fourth of saccus. Filum of distiphallus formed by 2 dark, very slender stripe-like twisted sclerites (the ventral being darker pigmented) terminating in membranous, dilated and flattened tip, apex of which is finely dentate. Ejacapodeme small, with slender digitiform projection.

Female differs from male as follows:

Total body length 2.06–2.31 mm.

First flagellomere often more darkened, ochreous brown externally. Notopleural and humeral areas sometimes paler brown than measonotum. Palpus and surrounding mouthparts usually darker brown than in male. f 3 posteroventrally simply setulose. Wing measurements: length 2.38–2.66 mm, width 0.67–0.75 mm, Cs 3: Cs 4 = 2.40–2.74, r-m\dm-cu: dm-cu = 3.52–3.35. Abdomen with preabdominal terga shorter and more transverse, completely dark brown. Preabdominal sterna S2–S5 about the same width, at most S2 slightly narrower than S3, all pale ochreous or S5 with pale brown darkened posterior and lateral margins ( Fig. 86 ).

Postabdomen ( Figs 85, 86 ). T6 large, only slightly narrower but longer than T5, densely shortly setose, dark brown. S6 markedly wider and darker brown than S5, and also wider than T7. T7 dark brown, narrow, posteriorly slightly tapered, anteriorly shallowly emarginate, with dense short setae in posterior two-fifths. S7 very distinct, anteriorly fused with ventrolateral corners of T7 and ornamented by bipartite (medially divided) dark pigmentation; posteriorly formed by an attached transversely oblong pale pigmented and setose plate ( Fig. 86 ). T8 also dark as T7, small, plate-shaped, with rounded posterior corners and fine setae in posterior half. S8 dark, distinctly narrower than T8, finely but rather long setulose, posteromedially strongly projecting and with narrow mediodorsal incision as usual. T10 small, moderate in length, dark and bare except for some microtomentum at indistinct posterior margin and with several (usually 4) posteromedial setae. S10 also dark, hardly wider than T10, micropubescent, with longer setulae at posterior margin. Internal sclerotisation of genital chamber composed of weak, pale pigmented and complexly bent posterior sclerites (two coalesced pairs) and of transverse, strongly twisted, slender, unpigmented anterior ring-shaped structure ( Fig. 84 ). Ventral receptacle ( Fig. 83 ) membranous, formed by pouch on proximal (internally pubescent) tube and digitiform, anteroventrally directed terminal projection. Spermathecae (1+1), one slightly larger than the other ( Fig. 82 ), spherical although slightly tapered towards duct insertion, each with small curved but blunt spines inserted on basal third of spermatheca; duct cervix well developed, relatively long. Cerci moderate, with short setae.

Discussion: A. obscurior sp.n. is somewhat intermediate between species of the A. thomasseti group and the A. sparsus group. Because it has white iridescent spots on wing and sinuous veins R 2+3 and R 4+5 and dark, heavily sclerotised male preabdominal sterna, it is considered a most primitive member of the latter group, although some other wing features (eg. large pale spot between R 4+5 and C) are similar to those of the A. thomasseti group. However, the latter features are considered plesiomorphic and do not demonstrate relationships of A. obscurior sp.n to this group. The new species has distinctive male genitalia (gonostylus, hypandrium, saccus) as well as female terminalia (S6, S7) and can also be identified according to wing pattern and venation, dark mouthparts and palpus, dark brown apical part of hind femur and blackish brown knob of haltere (see also key).

Biology: All type specimens were collected in January in the Semiliki Forest .

Distribution: The species is known only from Uganda.

Figures

Figs 77–81. Amygdalops obscurior sp.n., male paratype (Uganda). 77. External genitalia, caudal view. 78. Same, lateral view. 79. Hypandrium and associated structures, lateral view. 80. Gonostylus, sublateral view (widest extension). 81. Aedeagal complex, lateral view. Scales: Fig. 80 = 0.05 mm, others = 0.1 mm.

Figs 82–86. Amygdalops obscurior sp.n., female paratype (Uganda). 82.Spermathecae.83.Ventral receptacle, lateral view. 84. Internal sclerites, ventral view. 85. Postabdomen, dorsal view. 86. Postabdomen + 5th segment, ventral view.

Figs 129–132. Wings of Amygdalops species. 129. A. obscurior sp.n., male paratype (Uganda). 130. A. sparsus sp.n., male paratype (Uganda). 131. A. undulatus sp.n., male paratype (Madagascar). 132. A. poecilus sp.n., female paratype (South Africa). Scales = 0.5 mm.