Amygdalops thomasseti Lamb, 1914

Jindr, Rohác, ich & ek, 2004, Revision of the genus Amygdalops Lamb, 1914 (Diptera: Anthomyzidae) of the Afrotropical Region, African Invertebrates 45, pp. 157-221 : 168-171

Amygdalops thomasseti Lamb, 1914

( Figs 1–20 , 46–48, 123) Amygdalops thomasseti Lamb, 1914: 358 , Fig. 39 , Pl. 21, Figs 48–51 [description]; Sabrosky 1980: 650

[catalog, partim]; Rohác˘ek & Freidberg 1993: 92–98, Figs 64–83 , 119 [redescription]; Rohác˘ek

1998 a: 172 [world checklist, distribution], 1999 a: 194 [biology, distribution].

Type material: Lectotype male (designated by Rohác˘ek & Freidberg 1993: 94) labelled: ‘Mahe ‘0.8-9. Seychelles Exp.’, ‘ Seychelles Is., Prof. J. S. Gardiner 1914-537’, ‘Type ơ Amygdalops thomasseti C.G.L.’, ‘Type’ (on circular label with red margin), ‘ Lectotypus ” ơ Amygdalops thomasseti Lamb, Rohác ˘ek & Freidberg des. 1992’. The specimen is in poor condition, headless, with left wing and some legs missing; its abdomen detached (genit.prep.). Paralectotypes: female (headless) with same labels as the lectotype but with ‘Type ^ Amygdalops thomasseti C.G.L.’ and the paralectotype label; female labelled ‘Praslin, ’08. Seychelles Exp.’, ‘ Seychelles Is., Prof. J. S. Gardiner 1914-537, A. thomasseti Lamb’ (all in BMNH).

Other material examined: MADAGASCAR: near Ambilobe, Ankarana , viii.1986, 1 male, S. V. Fowler leg. ( NMWC) ; Andasibe , ca. 19ºS 48ºE, 13–15.x.1987, 1 male, SF McE, JRD, SA leg. ( AMSA) . MAURITIUS: vii. 1986, 1 female, J. R. David leg. ( AMSA) . MOZAMBIQUE: (Port East Africa), Luabo, Lower Zambesi River , vi– vii.1957, 1 female, Usher, Stuckenberg leg. ( NMSA) . SENEGAL: 1 km NE Djibelor, about 7.5 km SW Ziguinchor, UTM 28PCJ5687, loc. 29, swept along roadside in forest, 8.xi.1977, 1 female, Cederholm, Danielsson, Hammarstedt, Hedquist, Samuelsson leg. (Lund Univ. Syst. Dept.: Sweden-Gambia-Senegal Expedition , Nov. 1977, MZLU) . SEYCHELLES: Mahe , Beau Vallon, 4.xi.1997, 1 female, J. David & L. Tsacas leg. (Mission Seychelles C.N.R.S.-R.C.P. 318, Novembre 1977) ( BMNH) . SOUTH AFRICA: Tongaland, Ingwavuma District, Ndumu Reserve , 1–10.xii.1963, 2 females, B. & P. Stuckenderg leg. ; Natal, 6 miles S. of Pongola , 6.vi.1967, 2 females, South Africa Govn. Ent. leg. ( NMSA) ; SW Africa, Swakopmund , general sweeping, 26– 30.i.1972, 1 male 1 female, South African Exp. leg. ( BMNH) . UGANDA: S.W., Semiliki Forest , 1250 m, 8.i.1996, 6 males 2 females, I. Yarom & A. Freidberg leg. ( TAUI, SMOC) . Almost all specimens with genit. prep.

Description: Male.Total body length 1.67–2.37 mm. Body bicolorous, yellow and brown. Head somewhat longer than high, angular in profile ( Fig. 20 ). Frons narrow because of large convex eyes ( Fig. 1 ). Occiput pale brown, with paler postocular stripes. Frontal triangle narrow, reaching to anterior third of frons, brownish (including ocellar triangle) and rather shining. Anterior third of frons medially also ochreous to brown but usually paler than frontal triangle. Orbits yellowish brown to yellow (anteriorly), with whitish silver microtomentum reaching to posterior ors. Frontal lunule reduced. Face yellowish ochreous, narrow margin in front of eye and gena whitish yellow and with silvery white microtomentum. Cephalic chaetotaxy: pvt distinct, short but strongly convergent or crossed; vti long but shorter than vte; oc yet shorter and thinner than vti; 2 long ors and 2 small setulae in front of anterior ors ( Fig. 20 ); several microsetulae in front of frontal triangle; 1 long vi and 1 subvibrissa (about two-thirds of vi); a row of short peristomal setulae; also postocular setulae very short; palpus with 1 distinct seta. Mouthparts yellow. Eye very convex, elongately ellipsoid; its longest diameter about 1.6 times as long as shortest one. Gena anteriorly very narrow but widened posteriorly; its smallest height about 0.05 times as long as shortest eye diameter. Antenna knee-like bent; pedicel somewhat brownish ochreous and overlapping base of 1st flagellomere which is brownish around base of arista, otherwise yellowish white and long whitish ciliate on anterior corner.Arista about 1.8 times as long as antenna, very long pectinate, particularly dorsally ( Fig. 20 ).

Thorax narrower than head, bicolorous, brown to reddish brown and yellow. Mesonotum ( Fig. 1 ) brown except for two yellow to orange longitudinal stripes sometimes reaching up to scutellum but usually ending in front of it. Anteriorly these stripes can be widened and medially connected but in dark form (see below) these stripes are reduced and darkened, often poorly visible in foremost part of mesonotum only. Scutellum and postscutellum brown. Humeral and notopleural areas yellow; a narrow longitudinal stripe covering dorsal part of pleura (from propleuron to haltere) brown; rest of pleura yellow to whitish yellow. Thoracic chaetotaxy (see Fig. 1 ): 1 hu, 2 npl (anterior longer); 1 small prs; 1 weak sa and 1 longer pa; 2 dc but anterior only as long as sa, posterior very long; 4 rows of ac microsetae on suture; 2 sc, the long apical somewhat shorter than posterior dc; ppl indistinct; 2 stpl, the anterior shorter; ventral part of sternopleuron (katepisternum) with relatively short hair-like setae. Scutellum rounded triangular having slightly convex dorsal surface. Legs yellow to pale ochreous, coxae and trochanters whitish yellow. f 1 lacking ctenidial spine but bearing a row of posteroventral setae (usually 5 of them long) and a row of much shorter posterodorsal setae. t 2 with usual ventroapical seta. f 3 with a long row of posteroventral setae (15–18) becoming shorter and thicker distally ( Fig. 5 ). Wing ( Fig. 123 ) narrow, with pale brownish membrane ornamented by whitish area between C and R 4+5, darker brown diffuse areas along R 4+5, M and CuA 1 but mainly (darkest spot) at apices of R 2+3 and R 4+5. Veins yellowish brown. C without distinct spinulae. R 2+3 slightly diverging from C, apically upcurved to it and ending relatively far from apex of R 4+5. R 4+5 and M slightly divergent but apically convergent again. Discal cell short and narrow; r-m situated in its middle. CuA 1 and A 1 not reaching wing margin.Alula very narrow. Wing measurements: length 1.74–2.28 mm; width 0.52–0.75 mm, Cs 3: Cs 4 = 2.15–2.63, r-m\dm-cu: dm-cu = 2.44–3.00. Haltere normally yellow, with paler knob, more rarely with knob somewhat darkened, ochreous brown.

Abdomen: Terga wide, brown to dark brown (darker than mesonotum) except for T1 having laterodorsal pale ochreous spot on each side. T1–T5 large, with short setae. T6 reduced, weakly sclerotised and unpigmented, without setae. Sterna (S1+2 – S5) simple, narrow, pale yellow, with finer setulae than associated terga. S6–S8 asymmetrical, dark like preabdominal terga or epandrium, all dorsally fused. S6 (situated ventrolaterally) transversely strip-like, with somewhat widened dorsal portion; S7 situated on left side of postabdomen, about twice longer than dorsal part of S6; S8 long, longer than epandrium, situated quite dorsally.

Genitalia: Epandrium ( Figs 2, 4 ) rather small compared to internal genitalia, relatively sparsely setose and with a pair of longer setae. Cercus prominent, comparatively large. Medandrium ( Fig. 4 ) not wide, of medium size. Gonostylus ( Figs 3 , 47) proximally wide, distally tapered and with 1 preapical anterior tooth and narrow but not acute apex; its outer side with scarce setulae and distinct micropubescence; the majority of setae are on its inner side. Hypandrium not very robust but long ( Figs 8, 9 ), with membranous internal lobes; transandrium posteriorly with 2 sclerites ( Fig. 11 ) representing divided caudal process. Pregonite ( Figs 8, 9 ) basally fused with hypandrium, apically slender and projecting posteriorly, with several (5–6) setae. Postgonite ( Figs 8, 9 ) slender, apically acute and bearing 1 anterior seta in its middle; basal sclerite attached to postgonite weakly sclerotised but distinct.Aedeagal part of folding apparatus attached to base of phallapodeme ( Fig. 7 , afa) dorsally dark, ventrally provided with sclerotised lenticular grains; connecting sclerite pale pigmented, elongate. Basal membrane ( Figs 8, 11 , bm) distinctively sculptured by dense, transversely arranged, tuberculiform spines. Aedeagal complex ( Fig. 7 ) with robust phallapodeme having bifurcate base ( Fig. 10 ). Aedeagus with short phallophore and rather large distiphallus which is composed of voluminous, densely setulose saccus ( Fig. 7 ) and of slender twisted filum formed by 2 stripe-like sclerites. Apex of filum ( Fig. 6 ) membranous, with 2 very thin sclerotised stripes. Ejacapodeme small, with slender projection ( Fig. 7 ).

Female differs from male as follows:

Total body length 2.02–2.70 mm.

Occiput often paler than in male, yellowish brown. f 3 posteroventrally simply finely setulose. Wing measurements: length 2.12–2.74 mm, width 0.65–0.87 mm, Cs 3: Cs 4 = 2.04–2.65, r-m\dm-cu: dm-cu = 2.37–2.94. Abdomen with brown to reddish brown terga but T1 with pale spots in posterior corners and T4 and T5 with a pale spot on each side of their dorsal surface; size of these pale spots rather variable; sometimes they are small and invisible in dry specimens. Dark variety (see below) without pale spots on preabdominal terga. Preabdominal sterna (S1–S5) pale yellowish ochreous, becoming wider posteriorly, S5 slightly narrower than S6.

Postabdomen ( Figs 12–14 , 46) relatively short and wide. T6 wide, reaching on ventral side of abdomen. S6 comparatively wide, not narrower than preceding sterna, pale ochreous, in dark specimens with brownish posterior margin. T7 narrow, dorsomedially short because of anterior emargination, with dense short and thick setae. S7 with distinctive bipartite pigmentation ( Figs 14 , 46), poorly defined posterior margin and only few thin setae in posterior half. T8 dark, transverse, plate-shaped and more or less rounded anteriorly.S8 also dark, short, posteriomedially bulging and with distinct narrow posteromedial incision (surrounded by unpigmented area) only visible in caudal view ( Fig. 19 ). T10 very short and transverse, dark like T8 and with a pair of longer setae on posterior margin. S10 much longer but paler than T10, with a row of setulae at posterior margin. Internal sclerotisation of genital chamber complex ( Figs 17, 18 ), weakly sclerotised, pale pigmented, composed of anterior faint ring-shaped structure ( Fig. 18 ) and several twisted posterior sclerites of indefinite shape. Ventral receptacle (Fig. 48) membranous, slightly clavate subterminally, apically projecting in subventrally directed digitiform process. Spermathecae ( Figs 15, 16 ) ball-shaped, with short blunt spines or processes on surface of basal half, and with comparatively long sclerotised cervix. Cerci ( Fig. 12 ) comparatively short and robust, with moderate setosity.

Variability: The species is widespread in the Afrotropical region and southern Palaearctic areas which probably resulted in considerable variability of colour features. The most different from typical specimens is the dark form found in Uganda and Madagascar, which has more darkened frons, the longitudinal light stripes on mesonotum markedly reduced to almost invisible and the pale spots on female preabdominal terga very small or absent. There is a distinct variability in the pigmentation and setosity of the female S7 (cf. Figs 14 and 46) and also in the outline of the male gonostylus (cf. Figs 3 and 47); more slender gonostylus was also found in some specimens from South Africa and Madagascar. No distinct differences were observed in the male aedeagal complex of the dark form versus typical one and therefore the dark specimens are considered conspecific with A. thomasseti .

Discussion: A. thomasseti Lamb, 1914 together with A. obtusus sp.n., A. simplicior sp.n., A. major sp.n., A. acer sp.n. and A. nigrinotum Sueyoshi & Rohác ˘ek, 2003, forms a separate group which can be recognised by wing pattern characterised by subapical dark spot and (usually) pale narrow area between C and R 4+5. This character is however, plesiomorphic. The only true synapomorphy of this group, the shortened, frame-like phallophore, is rather weak and, consequently the monophyly of this group is not quite definite. A. thomasseti together with A. obtusus sp.n., forms a sister-pair of externally very similar species (including structures of frons and wing pattern), which are safely distinguished only by characters of the male and female genitalia. However, A. thomasseti has usually (except for darkest specimens) some of female preadominal terga ornamented with yellow or ochreous spots while the female of A. obtusus sp.n. has terga normally uniformly brown.

Biology: Poorly known. In the southern Palaearctic areas adults occur from March to December (Rohác˘ek & Freidberg 1993; Rohác˘ek 1999 a) and are usually found in marshy habitats, particularly in those with growths of Arundo donax , Phragmites australis and Scirpus maritimus along freshwater streams and canals in coastal areas. Sometimes they were also caught in light and Malaise traps and on decaying fruits (Rohác˘ek & Freidberg 1993). Records from Afrotropical Region are based on flies captured from April to January, usually by sweeping vegetation.

Distribution: A. thomasseti is widespread in the Afrotropical and southern Palaearctic Regions (see Rohác˘ek & Freidberg 1993; Rohác˘ek 1999 a). In the Afrotropical Region and adjacent areas it has been reliably recorded only from Seychelles ( Lamb 1914; confirmed by a new record here) and Oman (Rohác˘ek & Freidberg 1993) because other published records ( Sabrosky 1980) were apparently based on other species as no true A. thomasseti was found among Amygdalops material studied by C. Sabrosky in USNM (examined). The new Afrotropical records are as follows: Senegal, Uganda, Mozambique, South Africa, Madagascar, Mauritius.

Figures

Figs 1–5. Amygdalops thomasseti Lamb, male (Israel). 1. Head and thorax, dorsal view. 2. Genitalia, lateral view (hypandrium not dotted). 3. Gonostylus, sublateral view (widest extension). 4. External genitalia, caudal view. 5. Hind femur, posterior view. Scales: Figs 1, 5 = 0.2 mm, Fig. 3 = 0.05 mm, others = 0.1 mm. For abbreviations see text. Illustration according to Rohác˘ek & Freidberg (1993).

Figs 6–11. Amygdalops thomasseti Lamb, male (Israel). 6. Apex of filum, ventral view. 7. Aedeagal complex, lateral view. 8. Hypandrium and associated structures, lateral view. 9. Same, ventral view. 10. Basal part of phallapodeme, dorsal view. 11. Transandrium, caudal view. Scales = 0.05 mm. For abbreviations see text. Illustration according to Rohác˘ek & Freidberg (1993).

Figs 12–20. Amygdalops thomasseti Lamb, female, male (Israel). 12. Female postabdomen, dorsal view. 13. Same, lateral view. 14. Same, ventral view. 15, 16. Spermathecae. 17. Female internal sclerites (ring-shaped sclerite omitted), lateral view. 18. Same, ventral view. 19. Female S8, caudal view. 20. Male head, lateral view. Scales: Figs 12–14 = 0.1 mm, Fig. 20 = 0.2 mm, others = 0.05 mm. For abbreviations see text. Illustration according to Rohác˘ek & Freidberg (1993).

Figs 35–40. Amygdalops simplicior sp.n., male paratype (Cape Verde). 35. External genitalia, caudal view. 36. Same, lateral view.37.Transandrium, caudal view. 38. Hypandrium and associated structures, lateral view. 39. Gonostylus, sublateral view (widest extension). 40. Aedeagal complex, lateral view. Scales: Fig. 39 = 0.05 mm, others = 0.1 mm.

Figs 61–65. Amygdalops acer sp.n., male holotype. 61. External genitalia, caudal view. 62. Same, lateral view. 63. Transandrium, caudal view. 64. Aedeagal complex, lateral view. 65. Gonostylus, sublateral view (widest extension). Scales: Fig. 65 = 0.05 mm, others = 0.1 mm. For abbreviation see text.

Figs 66–70. Amygdalops nigrinotum Sueyoshi & Rohác˘ek, male (Figs 66, 67, 70 - paratype, Japan; Figs 68, 69 - Seychelles). 66. External genitalia, caudal view. 67. Same, lateral view. 68. Transandrium, caudal view. 69. Aedeagal complex, lateral view. 70. Gonostylus, sublateral view (widest extension). Scales: Fig. 70 = 0.05 mm, others = 0.1 mm.

Figs 71–76. Amygdalops nigrinotum Sueyoshi & Rohác˘ek, male (Seychelles), paratype female (Hawaii). 71. Hypandrium and associated structures, lateral view. 72. Postabdomen, dorsal view. 73. Same, ventral view. 74. Spermathecae. 75. Ventral receptacle, ventral view. 76. Left wall of female genital chamber (uterus). Scales: Figs 71–73 = 0.1 mm, others = 0.05 mm.

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 116–121. Amygdalops poecilus sp.n., female paratype (South Africa). 116. Postabdomen, dorsal view. 117. Spermatheca. 118. Ventral receptacle, lateral view. 119. Internal sclerites, ventral view. 120. Postabdomen, ventral view. 121. Spermatheca. Scales: Figs 116, 120 = 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.