Nesocordulia villiersi Legrand, 1984

Bernard, Rafał, Daraż, Bogusław, Ravelomanana, Andrianjaka & Dijkstra, Klaas-Douwe B., 2025, Six new species of Nesocordulia McLachlan, 1882 reveal an insular evolutionary radiation of dragonflies on Madagascar (Odonata: Anisoptera: Libelluloidea), Zootaxa 5660 (2), pp. 151-193 : 179-181

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 ).

Figures

FIGURE 2. Nesocordulia evanida sp. nov. (a) male habitus in lateral view; (b) female habitus in lateral view; (c) male head and thorax in dorsal view; (d) male secondary genitalia in lateral view; (e) male habitus in ventral view; (f) male abdomen in dorsal view; (g) male head in frontal view; (h) male terminalia in lateral view. Photos by Bogusław Daraż.

FIGURE 13. Nesocordulia villiersi, male. (a) habitus in dorsal view; (b) S7–10 and caudal appendages in lateral view; (c) synthorax and S1–2 in lateral view; (d) head in frontal view; (e) head in ventral view. Photos by Bogusław Daraż.

FIGURE 15. Lateral view of hamule and genital lobe of all species of Nesocordulia except N. flavicauda. Arranged according to similar form to aid comparison. Due to the poor quality of the available material, the actual shape of the N. malgassica hamule may differ in detail.

FIGURE 17. Lateral view of caudal appendages of all known species of Nesocordulia. Showed to scale. Hair-like setae not illustrated. Arranged according to similar form and size to aid comparison.

FIGURE 18. Dorsal view of caudal appendages of all known species of Nesocordulia. Showed to scale. Hair-like setae not illustrated. Arranged according to similar form and size to aid comparison.

FIGURE 19. Lateral view of synthorax of all known species of Nesocordulia. Arranged by extent and form of clear yellow spots (but not the indistinct brownish-yellow ones indicated by a slightly darker shade) to aid comparison. All darker colouration (i.e. more or less melanised, from reddish brown to black) is indicated by the dark shading.

FIGURE 21. Distribution of known localities of Nesocordulia. For further details see the species texts. “flavicauda?”— unconfirmed records in the Sambirano area; “Nesocordulia sp.”—several unidentified specimens from collections and photographs (see Fig. 14 and section “Unidentified specimens of Nesocordulia”).