Chlorogomphus canhvang, Kompier & Karube, 2018

Kompier, Tom & Karube, Haruki, 2018, Chlorogomphus canhvang sp. nov. from Central Vietnam (Odonata: Chlorogomphidae), Zootaxa 4394 (3), pp. 437-442 : 438-442

Chlorogomphus canhvang sp. nov.

( Figs. 1d–f , 2e–g , 3b–f )

Materials examined. Holotype ♂, Along QL 15, Quang Binh Province (appr. 17.488 N, 106.302 E), 6.V.2016, TK leg . Paratypes 1 ♀, same location and collector, 17.V. 2017 ; 1 ♂, same date, location and collector as holotype.

The holotype will be deposited at the Kanagawa Prefectural Museum of Natural History, Japan . Paratypes will be deposited at Naturalis Biodiversity Center (formerly Rijksmuseum van Natuurlijke Historie), Leiden, the Netherlands ( RMNH) .

Additional observations: Along National Road 14, Thua Thien—Hue Province (appr. 16.064 N, 107.485 E), 1 ♀ caught, photographed and released, 4.V.2016, TK.

Etymology. The specific name canhvang means “golden-winged” in Vietnamese (cánh vàng) in reference to the golden-winged appearance of the female and as a sister taxon to Chlorogomphus auratus , the name of which also refers to the golden wings of the female. An adjective in apposition.

Description of holotype. Head ( Fig. 3f ). Labium yellow, labial palps golden-brown. Labrum black with two small pale yellow spots in V-shape centrally below dorsal margin. Anteclypeus black with lower and upper margin bordered by pale yellow, narrowly connected over center. Postclypeus pale yellow with two small brown spots. Frons black, covered in black setae, in lateral view not noticeably protruding, in dorsal view anterior margin only slightly rounded covered in black setae; postfrons with thin greenish yellow line along anterior margin. Vertex conically raised, posterior surface slightly concave. Antennae black. Occiput black, forming a triangular pyramid, apex close to posterior margin, covered in long black setae. Compound eyes bright green.

Thorax ( Fig. 1d ). Prothorax matte black, anterior margin pale yellow and with small pale yellow area on lateral margins and center of posterior margin. Synthorax black with yellow markings as follows: A thin greenish-yellow dorsal stripe and a thin yellow antehumeral stripe on both sides, and a broad yellow band over the spiracle and covering most of the metepisternum. Ventral margin of metepimeron narrowly yellow. Coxae, legs, spines and claws all black.

Wings. Hyaline with black veins and apices edged narrowly dark brown. Nodal index 18–26: 28– 18 in FW, 20– 23: 21–22 in HW. Triangles 3-celled in FW and 3–4 celled in HW. Anal loop 18–19 celled, anal triangle 3-celled. Membranule grey. Pterostigma black, covering 3.5–4 underlying cells.

Abdomen ( Fig. 1d ). S1 black, but ventral third yellow; S2 black with broad yellow band laterally, from anteroventral corner over auricle towards posterior margin, which is narrowly black. S3 black with large anterolateral yellow markings that just connect to each other anteriorly over dorsal carina. S4–7 black with paired antero-dorsal spots, small on S4–6, but larger on S7. S8–10 black. The dorsal side of S10 curving downward in between the cerci to form a small nipple-like protrusion, not visible in lateral view ( Fig. 3d ).

Secondary genitalia ( Fig. 3c ). Black. Anterior lamina with undulating anterior margin and small inward directed apical hook, keeled posterior margin of posterior hamule in lateral view about 1.8 times as long as anterior lamina, thin, with apical hook weekly directed anteriorly.

Vesica spermalis ( Fig. 2g –h ). Similar to that of Chlorogomphus auratus ( Fig. 2c–d ), but second segment broader, with stout spine, the last segment somewhat more robust, its ventral plate somewhat more slender and more deeply notched apically.

Anal appendages ( Fig. 2e–f ). Black. Cerci about as long as S9, in lateral view broad at base, their dorsal margin almost straight, only slightly curving apically, and with a small blunt hump directed dorsad at their anterior end, their ventral margin more strongly curved, concave, their apex blunt. In dorsal view cerci widely separated, slightly diverging, subapically bifurcate, the outer branch shorter and directed somewhat ventrad, the inner branch apically slightly hooked laterally. The epiproct deeply incised, U-shaped in dorsal view, its branches virtually parallel-sided, minimally longer than cerci, in lateral view thickest in anterior half, curved upward and ending in a double tooth on the dorsal margin of their apex.

Measurements (in mm). HW 55.6; abdomen incl. appendages 59.6.

Variation in males. Paratype very similarly marked as holotype, but somewhat smaller: HW 52 mm and abdomen incl. appendages 52 mm. Nodal index 16–29:28– 16 in FW, 20–23:23– 19 in HW. Triangles 4-celled in all wings. Anal loop 16–18 celled. Pterostigma covering 4–4.5 underlying cells.

Description of female paratype. Head ( Fig. 3b, e ). As male, but vertex larger, postero-dorsal surface distinctly V-shaped.

Thorax ( Fig. 1e ). Prothorax as male but yellow spots on center of posterior margin larger. Synthorax as male. Coxae brown, legs, spines and claws all black.

Wings ( Fig. 1e ). Tinted golden, only minimally on antenodal part, strongest on postnodal part, with black veins and apices edged broadly dark brown, nodal index 18–28:30– 18 in FW, 21–24:23– 21 in HW. Triangles 5–6 celled in all wings. Anal loop 25–26 celled, anal triangle 3-celled. Membranule grey. Pterostigma black, covering 4–4.5 underlying cells.

Abdomen ( Fig. 1e ). Black with yellow markings as follows: S1 with small dorsal spot and yellow ventral half; S2 with broad band laterally, extending from antero-ventral corner over auricle towards posterior margin, which is narrowly black, and large antero-dorsal spot. S3 with anterior half almost completely yellow, but for ventral margin. S4–7 with partially fused antero-dorsal spots, largest on S7.

Cerci. Black.

Measurements (in mm). Hindwing 53; abdomen incl. cerci 55.

Variation in females. Female photographed from Thua Thien—Hue Prov. ( Fig. 1f ) with 31 Ax in left FW. The golden colour of the wings much more intense, also on antenodal part of wings, with dark spot on nodus and at wing base.

Differential diagnosis. The male is similar to the male of Chlorogomphus auratus , but easily separated by details of the anal appendages ( Fig. 2a–b, e–f ) and protusion on posterior margin of S10 ( Fig. 3d ). The epiproct is much deeper incised in C. canhvang , forming two parallel branches as long as the distance between them, more slender than in C. auratus and with the apical teeth directed more dorsally. In addition, the protrusion between the cerci formed by the posterior margin of S10 is only small and not visible in lateral view in C. canhvang , whereas it is clearly visible and stout in C. auratus . The shape of the female vertex is also different between the two species. It is postero-dorsally rounded in C. auratus ( Fig. 3a ), but V-shaped in C. canhvang ( Fig. 3b ). The antero-dorsal spots on S4–7 appear to be more similar in size in C. auratus ( Fig. 1b ), whereas in C. canhvang the spots on S7 are distinctly larger than those on S4–6 ( Fig. 1e–f ), although the validity of this character needs further study.

Habitat and ecology. Chlorogomphus canhvang was observed at small rocky streams under dense primary forest cover in low mountains (300–500m asl). The males flew on sunny days, but females were also active under cloudy conditions. Although the same locations were also visited several times in June under good and sunny conditions, no specimens could be located, so it is likely that the flight period of the species is during April–May, but does not extend into June. By contrast, C. auratus flies at least from early May to late July in northern Vietnam (T. Kompier pers. obs.)

Figures

FIGURE 1. Habitus of Chlorogomphus auratus [a–c] and C. canhvang [d–f]. (a) male, 23-VII-2017, Xuan Son National Park, Phu Tho Province; (b–c) female, 22-V-2015, Cuc Phuong National Park, Ninh Binh Province; (d) holotype male; (e) paratype female; (f) female, 4-V-2016, Thua Thien—Hue Province (posed for photo).

FIGURE 2. Comparison of anal appendages [a–b, e–f] and vesica spermalis [c–d, g–h] of Chlorogomphus auratus (Tam Dao NP, Vinh Phuc Prov.) [a–d] and C. canhvang, holotype [e–h]. (a, e) dorsal view; (b, f) lateral view; (c, g) lateral view; (d, h) ventral view of terminal segment.

FIGURE 3. Comparison of antero-dorsal view of female vertex [a–b], left lateral view of male secondary genitalia [c], posterior view of male posteriormargin of S10[d], and frontalview of head[e–f]. (a) Chlorogomphus auratus, 22-V-2015, Cuc Phuong National Park, Ninh Binh Prov.; (b, e) C. canhvang, paratype; (c–d, f) C. canhvang, holotype.