Nesocordulia villiersi Legrand, 1984 —Comoro Knifetail

Figs 13, 15, 17–19

Etymology. A noun in genitive singular dedicated to André Villiers, the French specialist of Afrotropical bugs and longhorn beetles who animated the new series of Revue Française d’Entomologie.

Type material. The holotype male (MNHN), Lac Iconi, Mohéli (Mwali) Island, Comoros, 11.1955, leg. A. Robinson. Iconi is a small watercourse and settlement (present name: Hamavouna), close to Dziani Boundouni Lake . As there are no other lakes nearby, this is probably the same lake as Lac Iconi .

Diagnosis. Rather small species (the second smallest Nesocordulia), uniquely occurring on the Comoros, but that is also distinct by its apically clubbed cerci, two-toned brown labium, and subtly different thoracic markings. Hamule similar to that of N. coloratissima (especially in lateral view) and N. evanida (in ventral view), albeit differing in the proportions and shapes of its anterior and posterior branches and the incision between them.

Description. Holotype male. Total length 45.1, abdomen (excluding appendages) 29.8, Fw 31.2, Hw 29.8, Fw Pt 1.9, cerci 2.1. Fw Ax 12, Fw Px 8, Hw Ax 6–7, Hw Px 11. Colouration generally black, dark brown and metallic, with yellow pattern (Fig. 13).

Head. Face dark, brown to black, partly with metallic reflections, and with a yellow centre (Fig. 13d). Vertex and postfrons metallic green and violet (Figs 13a,d). Frontal shield dark bronze with violet reflections (Fig. 13d). Frons sides mostly melanised with metallic green reflections, but centrally translucent dark yellow. Labrum glossy black (Fig. 13d). Labium two-tone brown, darker centrally, along the inner borders of lateral lobes (Fig. 13e). Occipital triangle black. Postgenae black.

Thorax. Synthorax largely dark purplish-brown and metallic, with mostly green and blue, and locally copper reflections (Fig. 13c). The whole mesepisternum melanised, metallic blue and green. Mesokatepisternum dark purplish-brown with a small yellow spot. Synthoracic sides with four pale yellow spots in two lines (Figs 13c, 19). In the upper line, a quite large mesepimeral spot, irregularly triangular and pointing dorsally, and the uppermost smaller metepisternal spot, bullet-like and also pointing dorsally. In the lower line, two markings along the lower margin of the synthorax: a small spot on the metakatepisternum, below the metastigma, and a much larger and oblong spot, situated centrally in the posterior half of metepimeron and almost adjacent to the yellow poststernum. Legs mostly chocolate brown (Fig. 13c).

Wings. Membrane hyaline. Pt short, brown (Fig. 13a).

Abdomen. Black and basally dark brown, with paired yellow pattern. The laterodorsal spots on each side of S2 small: the anterior spot rectangular, with tapered tip directed dorsally, and the posterior one oval (Fig. 13c). The lateroventral yellow spot on each side of S2 stretched along the whole segment’s length, broader posteriorly (Fig. 13c). The laterodorsal yellow pattern on S3–6 reduced and consisting of anterior stripes on S3 and S4 (narrow), and posterior narrow stripes on S3 only. Two basal laterodorsal yellow spots on S7 roundish and small, covering at most one fifth of the segment’s length (Fig. 13b) and broadly diverged along the dorsal carina. Pattern along the ventral carina: (a) on S3–5, an indistinct yellowish brown line, broadened yellow anteriorly on S3 only; (b) on S6–7, the pattern indiscernible; (c) on S8–9, a broad brownish stripe with yellow spots, on S 8 in its central and posterior sections, on S 9 in its anterior section; on both segments spots visible in lateral view.

Secondary genitalia. In lateral view, the hamule with a shallow and wide, rectangular apical incision between the anterior and posterior branch, the former being short and blunt and the latter slightly longer, much broader and bluntly rounded apically (Figs 13c, 15). In ventral view, the inner lobe of the anterior branch broadly rounded inwards and the posterior external branch twisted inwards and visible as a roundish finger-like projection (see Fig. 2 in Legrand 1984). Genital lobe bluntly triangular, pointing obliquely downwards, with yellowish ochre hair-like setae (Fig. 15).

Caudal appendages. Cerci fairly short, bicoloured, brown in basal half and creamy white in distal half, with buffy greyish hair-like setae (Fig. 13b). In dorsal view, gently arched inwards, with distended tips (Figs 13a, 18). In lateral view, almost straight and apically swollen in a rounded ‘head’ (Figs 13b, 17); a small lateroventral bulge discernible at a quarter of the length. Epiproct warm brown, long, reaching 95% of the cerci length (Figs 13b, 17).

Female. Unknown.

Distribution. Only known from the type locality on the Comoros, somewhere between the coastal lowlands and hills of southeastern Mohéli, i.e. about 450 km from Madagascar (Fig. 21).