Centrioncus decellei Feijen, 1983

Feijen, Hans R. & Feijen, Cobi, 2023, A revision of Centrioncus Speiser (Diptera, Diopsidae, Centrioncinae) with descriptions of new species from Angola, Burundi, and Kenya, ZooKeys 1144, pp. 1-93 : 1

Centrioncus decellei Feijen

Figs 110 , 111

Centrioncus decellei Feijen, 1983: 73.

Type material.

Ivory Coast, holotype ♀, Amanikro, 50 km nw of Abengourou [7°1'0"N, 3°52'0"W, 52 km NW of Abengourou, 194 m], ix. 1961, J. Decelle (MRAC) (not examined, but notes and pencil drawings for Feijen (1983) were used).

Diagnosis

(after Feijen 1983). Centrioncus decellei can be recognised by the flat, uniformly pruinose frons; pruinose blackish brown scutum, brownish humeral calli, chestnut-brown lateral edges; scutellum blackish brown with brown edges and lateral sides, scutellar spines yellowish; blackish brown pleura, brown anterior part of anepisternum and posterior part of anepimeron, katepisternum with brown spot anteriorly; scutellum projecting at angle of 45° from body axis; pale brown fore femur on distal half of inner side with dark brown, stripe-like spot, with ~ 38 tubercles; small, elongate, very vague, brownish central spot around crossvein r-m (Fig. 110 ), in tip of cell br, mainly in posterior part of basal quarter of cell r4+5, slightly extending into cell bm+dm; vein M4 distally of crossvein dm-m curving downward towards wing margin; tergites blackish brown, apical edges paler; female 7th spiracle in tergite (Fig. 111 ); female tergite 7 with small mesal gap at posterior edge; female tergite 10 with 3 pairs of setulae; trapezoidal anterior sclerite of female sternite 7 narrow (w/l ratio: ~ 2.7); posterior sclerite of female sternite 7 rounded U-shaped, relatively short lateral arms with tri-lobed posterior apices (Fig. 111 ); female cercus elongate, l/w ratio: 4.1; subanal plate triangular, with convex lateral sides; spermathecae wrinkled, with a dimple and some tiny tubercles.

Supplementary description.

Wing. Small, elongate, very vague, brownish central spot around crossvein r-m (Fig. 110 ), in tip of cell br, mainly in posterior part of basal quarter of cell r4+5 to three-quarters distance to crossvein dm-m, slightly extending into cell bm+dm; vein CuA+CuP from vein CuP onward extending under angle of 25° to wing margin in straight line; vein M4, especially distal of crossvein dm-m, curving downward to wing margin (Fig. 110 ).

Female postabdomen. Anterior sclerite of sternite 7 trapezoidal with w/l ratio: ~ 2.7 (Fig. 111 , Table 8 ); posterior sclerite of sternite 7 rounded U-shaped, with relatively short lateral arms, with 3-4-lobed posterior apices (Fig. 111 ); female cercus elongate with l/w ratio: 4.1 (Table 8 ); subanal plate triangular with convex lateral sides.

Distribution and habitat.

There are several Amanikro locations in Ivory Coast, three of which are north-west of Abengourou. However, given the label distance of 50 km from Abengourou, the correct collecting location must be Amanikro at 7°1'0"N, 3°52'0"W, 52 km NW of Abengourou, 194 m. The holotype was collected in lowland forest. This species is the only Centrioncus known to occur at a low altitude, while the single specimen is also the only Centrioncus known from West Africa.

Figures

Figures 110, 111. Centrioncus decellei, ♀, holotype, Amanikro, Ivory Coast 110 wing, dorsal view 111 sternite 7, ventral view. Scale bars: 0.5 mm (110); 0.1 mm (111). Both drawings were processed, based on original pencil drawings from Feijen (1983: figs 12, 26).