Argopistes keiseri sp. nov.

Figs 4, 8 A

Type material.

Holotype ♂: “ Madagascar / Tamatave prov. / Manankazo env. / 11-12.11. 1995 / Ivo Jeniš leg. ” [printed on white card] [17 ° 59.26 ' S; 46 ° 54.20 ' E] (BAQ) . Paratypes. 1 ♂ and 1 ♀ “ Madagascar Tam. / Moramanga / 20. xii. 1957 F. Keiser ” [printed on pink card] // “ Non Cocc. Det. H. Fürsch ” [printed on white card] [18 ° 56.93 ' S; 48 ° 13.47 ' E] (NHMB) ; 2 ♀♀, “ Madagascar / Tamatave prov. / Moramanga env. / 24.2- 1.3. 1995 / Ivo Jeniš leg. ” [printed on white card] [18 ° 56.93 ' S; 48 ° 13.47 ' E] (BAQ) ; 2 ♀♀, “ Madagascar / Tamatave prov. / Moramanga env. / 25-27.11. 1995 / Ivo Jeniš leg. ” [printed on white card] [18 ° 56.93 ' S; 48 ° 13.47 ' E] (BAQ) ; 2 ♀♀, “ Madagascar / Tamatave prov. / Moramanga env. / 21-24.12. 1996 / Ivo Jeniš leg. ” [printed on white card] [18 ° 56.93 ' S; 48 ° 13.47 ' E] (BAQ) ; 1 ♂ and 1 ♀, “ Madagascar / Tamatave prov. / Maromizaha / 21. II. 1995 Ivo Jeniš ” [printed on white card] [18 ° 58.57 ' S; 48 ° 27.90 ' E] (BAQ) ; 2 ♂ and 3 ♀, “ Madagascar / Fianarantsoa prov. / Ranomafana env. / 28. I- 6. II. 1995 Ivo Jeniš ” [printed on white card] [21 ° 15.76 ' S; 47 ° 27.12 ' E] (BAQ) .

Diagnosis.

Argopistes keiseri sp. nov. shows major similarities with A. seyrigi sp. nov. Both have the spur of hind tibiae distinctly elongate, extending significantly beyond the tibial apex (Figs 4 B, 6 B), black dorsal integuments (Figs 4 A, 6 A), and mostly confused elytral punctation. Argopistes keiseri sp. nov. can be distinguished by the blackish abdomen and tibiae (mostly reddish brown in A. seyrigi sp. nov.) (Figs 4 B, 6 B). Both the median lobe of aedeagus and spermatheca are diagnostic for Argopistes keiseri sp. nov.: median lobe (Fig. 4 D) is thickset, with irregular outline in ventral view, and clearly sinuate in lateral view; spermatheca (Fig. 4 C) has sinuate basal part and elongate, U-shaped, and uncoiled ductus.

Description of the holotype

(♂). Body roundish in dorsal view (Fig. 4 A), strongly convex in lateral view; total length of body (LB) = 3.48 mm; maximum pronotal width at the base (WP = 2.08 mm); maximum width of elytra in the middle (WE = 3.16 mm); WE / WP = 1.52. Dorsal integuments (Fig. 4 A) entirely black with weak metallic reflections; ventral parts (Fig. 4 B) entirely blackish; head black; frons and mouthparts black, with yellowish maxillary palpi; antennae yellowish (Fig. 4 B); legs, including articulations, black, with yellowish tarsi (Fig. 4 B). Head entirely hidden by the pronotum; vertex punctate, with a pair of large setiferous pores; area of frontal calli weakly raised; frons moderately elongate, roughly wrinkled; frontal ridge thin, weakly raised; frontogenal sutures thin, strongly raised; eyes large, elongate, slightly kidney-shaped; interantennal space clearly narrower than antennal sockets. Antennae (Fig. 4 B) filiform, distinctly shorter than 1 / 2 the body length (LAN = 1.44 mm; LAN / LB = 0.41); segments 1–2 thicker; segments 3–11 slightly and gradually flattened; LA = 100: 51: 47: 53: 37: 48: 44: 64: 51: 50: 88. Pronotum (Fig. 4 A) distinctly transverse (LP = 1.00 mm; WP / LP = 2.08); lateral margins strongly convergent anteriorly, straight, weakly expanded, not visible in dorsal view; basal margin arcuate and distinctly sinuate; surface sparsely micropunctate, with dense, small punctation; surface moderately raised parallel to the lateral margins; a large setiferous pore at the anterior angles. Scutellum small, subtriangular. Elytra (LE = 3.20 mm; LE / LP = 3.20) strongly curved laterally (Fig. 4 A), approx. as long as wide (WE / LE = 1.02), jointly rounded apically; lateral margins finely bordered, visible in dorsal view; surface smooth; punctation small, dense, mostly confused, but arranged in some regular lines laterally, of which one is made of slightly larger punctures. Humeral calli moderately raised. Macropterous. Prosternum with posteriorly open procoxal cavities and large intercoxal prosternal process. Mesosternum very short. First abdominal sternite slightly longer than fifth (Fig. 4 B); its central area bordered by ridges is quite wide, slightly narrowing posteriorly. Anterior and middle legs without modifications. Posterior femora greatly swollen (WF / LF = 0.68), elongate-subtriangular; posterior tibiae thick, distinctly shorter than femora, apically widened and prolonged into a spur-like process on inner side; outer side of hind tibia apically toothed; apical spur of hind tibiae simple, lanceolate, very elongate; first metatarsomere moderately enlarged. Median lobe of the aedeagus (LAED = 1.26 mm; LE / LAED = 2.54) (Fig. 4 D) with smooth surface; in ventral view thickset, lanceolate but with slightly irregular outline; in lateral view median lobe moderately curved, thicker at the subapical part, with sinuate ventral outline; apex ventrally oriented; dorsal ligula formed by a central lobe medially incised in the apical part, and two thinner lateral lobes; its base at apical ~ 1 / 3.

Variability.

Male (n = 5; mean and standard deviation; range): LE = 3.08 ± 0.13 mm (2.88 ≤ LE ≤ 3.20 mm); WE = 2.98 ± 0.13 mm (2.82 ≤ WE ≤ 3.16 mm); LP = 0.92 ± 0.06 mm (0.86 ≤ LP ≤ 1.00 mm); WP = 1.98 ± 0.09 mm (1.88 ≤ WP ≤ 2.08 mm); LAN = 1.39 ± 0.15 mm (1.16 ≤ LAN ≤ 1.52 mm); LAED = 1.38 ± 0.09 mm (1.26 ≤ LAED ≤ 1.48 mm); LB = 3.37 ± 0.12 mm (3.20 ≤ LB ≤ 3.48 mm); LE / LP = 3.35 ± 0.11 (3.20 ≤ LE / LP ≤ 3.50); WE / WP = 1.50 ± 0.03 (1.44 ≤ WE / WP ≤ 1.53); WP / LP = 2.16 ± 0.04 (2.08 ≤ WP / LP ≤ 2.19); WE / LE = 0.97 ± 0.03 (0.94 ≤ WE / LE ≤ 0.99); LAN / LB = 0.41 ± 0.04 (0.35 ≤ LAN / LB ≤ 0.45); LE / LAED = 2.24 ± 0.18 (2.04 ≤ LE / LAED ≤ 2.54). Female (n = 11; mean and standard deviation; range): LE = 3.35 ± 0.04 mm (3.32 ≤ LE ≤ 3.40 mm); WE = 3.20 ± 0.06 mm (3.12 ≤ WE ≤ 3.24 mm); LP = 1.02 ± 0.03 mm (0.98 ≤ LP ≤ 1.04 mm); WP = 2.10 ± 0.05 mm (2.02 ≤ WP ≤ 2.12 mm); LAN = 1.34 ± 0.08 mm (1.28 ≤ LAN ≤ 1.44 mm); LSPC = 0.40 ± 0.01 mm (0.38 ≤ LSPC ≤ 0.40 mm); LB = 3.66 ± 0.07 mm (3.58 ≤ LB ≤ 3.72 mm); LE / LP = 3.30 ± 0.07 (3.23 ≤ LE / LP ≤ 3.39); WE / WP = 1.53 ± 0.01 (1.51 ≤ WE / WP ≤ 1.54); WP / LP = 2.06 ± 0.04 (2.04 ≤ WP / LP ≤ 2.12); WE / LE = 0.96 ± 0.02 (0.94 ≤ WE / LE ≤ 0.98); LAN / LB = 0.37 ± 0.01 (0.35 ≤ LAN / LB ≤ 0.39); LE / LSPC = 8.49 ± 0.19 (8.30 ≤ LE / LSPC ≤ 8.74).

Male and female paratypes very similar in shape, size, and color to the holotype. The arrangement of elytral punctation in 9 (+ 1 sutural) regular rows is better visible in some specimens. Spermatheca (Fig. 4 C) with subcylindical, sinuate basal part; collum short; apical part moderately elongate, gradually narrowing, slightly wrinkled; ductus subventrally inserted, quite thickset, elongate, U-shaped, uncoiled.

Etymology.

The specific epithet refers to the first collector of the new species: Alfred “ Fred ” Kaiser (1895–1969) from Switzerland, renowned expert on Diptera Syrphidae from Madagascar.

Distribution.

Central-Eastern Madagascar (Toamasina province; Fig. 8 A). Malagasy chorotype.

Ecological notes.

Host plant unknown. Collection localities fall within areas characterized by the vegetation division ‘ Malagasy Evergreen & Semi-Evergreen Forest’.