Nesocordulia ipsio Bernard, Daraż & Dijkstra, 2025

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 : 162-164

Nesocordulia ipsio Bernard, Daraż & Dijkstra sp. nov. —Dark Knifetail

Figs 5 , 15–19 , 20a,b

http://zoobank.org/ urn:lsid:zoobank.org:act:9627EDCE-FC92-48EC-8839-E629984BDC35

Etymology. The name, a noun in apposition, refers to the CEPF project Insects and People in the Southern Indian Ocean (IPSIO), initiated by Brian Fisher at the Madagascar Biodiversity Center. K.-D.B. Dijkstra participated in the IPSIO expedition to Marojejy National Park, but all specimens were collected by Alan Gardiner while he was seeking for butterflies.

Type material. Holotype male ( RMNH.INS.1552536) and four paratypes: male ( RMNH.INS.1552534) and three females ( RMNH.INS.1679788, 1679790, 1679791). All from the ridge below Simpona Camp (“camp 3”), 14.4377° S, 49.7544° E, 1,150 m asl, Marojejy National Park, Sava Region, Madagascar, 09– 13.02.2018, leg Alan Gardiner.

Photographic records. Female (identified by us from the photograph), vicinity of Mantella camp, 14.4376° S, 49.7756° E (approximate location), 480 m asl, Marojejy National Park, Sava Region, 01.2012, photo by user name “globalherping” (https://www.inaturalist.org/observations/224246873).

Diagnosis. Medium-sized Nesocordulia species with a uniquely shaped hamule (see Fig. 15 ) and the most extensive and contrasting dark markings on the labium and cerci in the genus. Only the presumably closely related N. odonator is similarly dark, sharing the limited thoracic pattern of small yellow spots, divided yellow lateroventral marking on S2, the laterally long but dorsally interrupted yellowish basal ring on S7, and dark epiproct. Nesocordulia ipsio differs from it, however, by a different hamule (see Figs 15 and 16 ) and mostly blackish brown lateral lobes of labium, and is also significantly smaller.

Description. Holotype male. Total length 46.9, abdomen (excluding appendages) 32.2, Fw 34.9, Hw 33.5, Fw Pt 1.9, cerci 2.2. Fw Ax 11–12, Fw Px 8–9, Hw Ax 7, Hw Px 11. Colouration generally dark, mostly black and locally brown, and with metallic reflections and yellow pattern ( Fig. 5a ).

Head. Face dark, with rich metallic reflections and a yellow centre ( Fig. 5f ). Vertex metallic, blue and violet. Frons metallic, with dark bronze frontal shield and green, blue, violet and copper reflections ( Figs 5a,f ). Clypeus yellow to olive-yellow centrally, and metallic green (with golden and purplish reflections) laterally ( Fig. 5f ). Labrum glossy black, locally with metallic violet reflections ( Fig. 5f ). Labium with median lobe brown and lateral lobes largely blackish brown and only narrowly yellow and buff on outer borders, like crescents ( Fig. 5g ). Occipital triangle black. Postgenae black.

Thorax. Synthorax mostly richly metallic (green, blue, violet, purple, bronze and copper), interspersed with brown, and with small yellow markings ( Figs 5a , 19 ). Mesepisternum metallic (green and blue) in the upper half and brown in the lower half. Mesokatepisternum brown. On the synthoracic sides, four yellow spots in two lines ( Figs 5a , 19 ). In the upper line, the mesepimeral spot, small and triangular, situated opposite the metastigma, and the metepisternal spot, a larger inverted triangle, darker yellow and slightly blurred. In the lower line, two small spots along the lower margin of the synthorax, on the metakatepisternum below the metastigma and on the metepimeron, the latter much less than half as long as the posterior border of metepimeron and not reaching poststernum. Poststernum dark brown.

Wings. Membrane tinted with yellow at base. Pt short, brown.

Abdomen. Black with paired yellow pattern ( Fig. 5a ). The laterodorsal yellow spots on each side of S2 are of different size: the anterior broad and short, with tapered tip directed dorsally, and the posterior small and oval. Lateroventral yellow marking on each side of S2 divided into two small well-separated spots: the anterior spot additionally split in two uneven parts while the posterior one broad and rectangular ( Figs 5a , 16e ). The laterodorsal yellow pattern on S3–6 consists of anterior stripes on each segment (the shortest and partly disintegrated on S6) and posterior stripes on S3 only ( Fig. 5a ). S7 with a basal dorsolateral creamy white ring covering one fifth of the segment’s length and not reaching the supplementary transverse carina, but far-extended laterally; dorsally, the ring is divided by a narrow black line along the dorsal carina ( Figs 5a,d ). Along the ventral carina ( Fig. 5c ): (a) on S3–6, a thin yellow line, broadened anteriorly on S3 only; (b) on S7, a rather broad yellow stripe turning brown distally; (c) on S8, a small basal yellow marking broadened distally and laterally into a large rounded brown spot; (d) on S9, a brown basal spot; the brown spots visible in lateral view of S8–9.

Secondary genitalia. In lateral view, the hamule large, with both branches ear-like, broad and rounded, but the posterior branch much shorter and two-coloured, dark with pale margin ( Figs 5a , 15 ). In ventral view, the inner lobe of the anterior branch of the hamule ear-shaped and broadly rounded inwards, with pale tip of the posterior external branch visible below ( Fig. 16e ). Genital lobe black, directed straight downwards and almost as the hamule long ( Figs 5a , 15 ), with rusty and buffy hair-like setae.

Caudal appendages. Cerci fairly short, their basal two-thirds dark (black and dark brown), with brownish shade reaching up to 80% of the length and white tips covered with contrasting dark hair-like setae ( Figs 5d,h ). In dorsal view, gently arched inwards, with a longer (60%) inward arm and a shorter outward arm bluntly tapered apically ( Figs 5d , 18 ). In lateral view, arched up and slightly distended in their distal half, with tapering tips and cut apices ( Figs 5h , 17 ). Epiproct blackish to dark brown and fairly long, reaching 80% of the cerci length ( Figs 5h , 17 ).

Variation in males. The paratype male is slightly larger and even darker. Total length 47.4, abdomen (excluding appendages) 32.8, Fw 35.3, Hw 34.0, Fw Pt 1.9, cerci 2.1. Fw Ax 11, Fw Px 8, Hw Ax 8, Hw Px 10–11. Minute differences in the colour pattern versus the holotype: (a) the anterior laterodorsal stripes on S5 and S6 vestigial; (b) yellow and brown pattern along the ventral carina of S3–9 partly darkened and disintegrated. Epiproct slightly longer, reaching 85% of the cerci length.

Paratype females. Total length 46.1–48.2, abdomen (excluding appendages) 32.5–33.7, Fw 37.1–38.3, Hw 36.9–37.5, Fw Pt 1.9–2.0. Fw Ax 12–13, Fw Px 8–10, Hw Ax 7–8, Hw Px 10–12. Colour pattern very similar to that of males, with the following minor differences: (a) the anterior lateroventral spot on S2 irregular and not split ( Fig. 5b ); (b) the posterior laterodorsal stripe on S4 vestigial ( Fig. 5b ); (c) the basal ring on S7 reduced to two laterodorsal yellow spots broadly separated dorsally ( Figs 5b,e ); (d) in two females, the darkened yellow pattern along the ventral carina, especially in posterior parts of S3–6. Variation mostly in dimensions and numbers of cross-veins. Anterior processes of gonapophyses on S8 (subgenital plate) take the form of two large triangular arms, dark with yellow edges ( Figs 20a,b ); their sharp yellow tips touch each other or overlap, and are visible in lateral view as spines protruding below the ventral corners of S8 tergites. Median processes on S9 are shaped like relatively long ‘viking’ horns ( Figs 20a,b ). Cerci short (1.0), in dorsal view dark basally (one third to half the length) and yellowish white distally ( Fig. 5e ).

Distribution and ecology. Known only from Marojejy National Park in northeastern Madagascar ( Fig. 21 ), in the ecoregion of Madagascar Humid Forests ( One Earth 2024) and the hydrographic ecoregion of Eastern Highlands ( Sparks & Stiassny 2022). All individuals collected over path along the top of a mountain ridge with low cloud forest at 1,150 m asl, and one female photographed at much lower elevation at 480 m asl.

Figures

FIGURE 5. Nesocordulia ipsio sp. nov. (a) male habitus in lateral view; (b) female habitus in lateral view; (c) male abdomen in ventral view; (d) posterior part of the male abdomen in dorsal view; (e) posterior part of the female abdomen in dorsal view; (f) male head in frontal view; (g) male head in ventral view; (h) male terminalia in lateral 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 16. Secondary genitalia in ventral view of the six new species of Nesocordulia: (a) N. coloratissima, (b) N. evanida, (c) N. lyricauda (only right side recognisable, the left one damaged), (d) N. odonator, (e) N. ipsio, and (f) N. fossa. Arranged vertically (head upwards) to aid comparison. Photos by Bogusław Daraż.

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 20. S8–9 of female Nesocordulia in ventral view, with gonapophyses: anterior processes (subgenital plate) on S8 and median processes on S9. a–b, N. ipsio; c–d, N. coloratissima, on figure d the anterior processes (subgenital plate) covered by tergites and only their common base discernible; e, N. evanida (the teneral female preserved in poor condition), the anterior processes (subgenital plate) partly covered by tergites (dotted line). Photos by Bogusław Daraż.

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”).