Coeliccia lephuocdieui Phan & Ngo & Bui 2020, sp. nov.

Coeliccia lephuocdieui sp. nov.

(Figures 1, 2a, 3 a–b, 4a–b, 5, 6a–b, 8a)

Type material. Holotype: ♂, a fully mature male, mountain top near the headquarters of the Kon Ka Kinh NP (14.2586N, 108.3786E; altitude 1489 m), Ayun Commune, Mang Yang District, Gia Lai Prov., 21 iv 2019, Q. T. Phan & Q.P. Ngo leg.

Paratypes: 3 ♂♂, 3 ♀♀, all mature, same data as holotype; 1 ♂, fully mature, same location as holotype, 04 iv 2018, To Van Quang leg.

Type deposition. All type specimens of the new species are deposited in the Zoological Collection of Duy Tan University, Da Nang, Vietnam.

Etymology. The species is named lephuocdieui in memory of our friend, Mr Le Phuoc Dieu (born December 07, 1984, deceased May 24, 2019) of Quang Tri Province, Vietnam. A noun in the genitive case.

Description of holotype. Head (Figs 2a, 5c). Labrum, anteclypeus, postclypeus, genae and mandibles shining black; front of head and antennae matte black except for top of first segment dark yellowish. Dorsum of head matte black excluding two narrow stripes adjacent to posterior ocelli and two oval yellowish postocular spots. Compound eyes bicoloured in life, black above and green below (Fig. 8a).

Thorax (Fig. 2a). Prothorax: black apart from dark yellow marking on middle pronotal lobe. Synthorax: mesepisternum and mesepimeron entirely black; metepisternum and metepimeron with two distinct large yellow markings as in Figure 2a (pattern greenish-yellow in living individual, Fig. 8a). Mesinfraepisternum and metinfraepisternum entirely black. Legs (Fig. 2a). Coxae and trochanters black with dark yellowish marking. Femur and tibia pale yellowish with black lines. Spines and claws black.

Wings. Hyaline, 18 px in FW and 17 in HW. Pt brown, covering 2 underlying cells.

Abdomen (Figs 1a, 3 a–b). S1 largely whitish, black dorsally; S2–6 black dorsally, whitish ventrally with subapical white annulus from S3–6; S8–9 largely black, ventral margin with yellowish stripe; S10 black dorsally (Fig. 3a), lateral and ventral yellowish (Fig. 3b).

Anal appendages (Fig. 3 a–b) yellowish apart from black ventral margin of cerci and tip of paraprocts. Cerci as long as S10, ventral side with blackish carina, forming a point. Paraprocts slightly longer than cerci, gently rising with tip curved medially and ending in a black tooth. In dorsal view (Fig. 3a), cerci yellowish, apex smoothly rounded but in lateral view (Fig. 3b), cerci expanding near base, tip acute.

Genital ligula (Fig. 4 a–b) bifurcate distally with a pair of long flagella. Terminal segment with a large triangular-shaped flap distally and thin apical fold.

Measurements (in mm). HW 30; abdomen including appendages 46.

Variation in paratype males. One male smaller: HW 28 mm, abdomen including appendages 42 mm, but higher number of px, 21 in FW and 20 in HW. In another paratype male, prothorax entirely black, not dark yellowish as in holotype and HW 29 mm, abdomen including appendages 43 mm. The other paratype male with HW 30 mm, abdomen including appendages 48 mm, the number of px as in holotype.

Description of female. Head (Fig. 5 a–b). Labrum and postclypeus entirely shining black. Anteclypeus yellow with two black spots left and right on lower margin. Mandibles and genae yellow, this pattern connecting above with postclypeus. Head dorsally matte black with two long yellow stripes each extending from eye margin to posterior ocellus, two oval yellow spots adjacent the anterior ocellus and two oblong yellowish postocular spots. Antennae black, top of first segment yellow. Compound eyes in life as in the male (Fig. 8a), black dorsally and greenish below.

Thorax (Figs 5a, 5d, 6 a–b). Prothorax: Anterior, posterior and dorsal of middle pronotal lobes black, remaining area yellowish (Fig. 5a, d). Posterior margin of posterior pronotal lobe slightly convex in lateral view (Fig. 6a), triangular-shaped in dorsal view (Fig. 6b) and with two distinct lapels. Synthorax (Fig. 5a): mesepisternum with a long, narrow yellowish antehumeral stripe; mesepimeron entirely black; metepisternum and metepimeron mostly yellow except for narrow metepleural black stripe along lower margin of metepisternum. Mesinfraepisternum and metinfraepisternum entirely yellow. Legs as in the male.

Wings. Hyaline, 19 px in FW and 18 in HW. Pt brown, covering 1.5 underlying cells.

Abdomen (Figs 2b, 5e). S1 largely yellow with posterior margin and dorsum narrowly black; dorsal half S2 black, yellow ventrally; S3–7 dark brownish dorsally, ventral margin yellowish with subapical yellow annulus; S8 black with an oval yellowish spot laterally, lower margin with yellow stripe; S9–10 mostly yellowish, ventral and posterior margin black (Fig. 5e).

Anal appendages (Fig. 5e). Cerci black, half S10; ovipositor black with yellow anterior marking dorsally at apex.

Measurements (in mm). Hind wing 30; abdomen including appendages 43.

Variation in paratype females. Paratype females show no significant morphological differences from female used for the description apart from size, ranging from 30–31 mm (HW), 41–44 mm (abdomen including appendages) and px 19–21 in FW and 18–20 in HW.

Habitat and ecology. Adults were collected at a dry narrow, densely vegetated stream within a humid, pristine forest (Fig. 9 a–b).

Differential Diagnosis. Within Coeliccia, the new species and C. scutellum, C. hainanense Laidlaw, 1932, C. renifera (Selys, 1886), C. svihleri Asahina, 1970 and C. yamasakii can be defined as a group characterized by the combination of following male characters: synthorax with three separated large yellowish (sometimes greenish) markings (apart from C. lephuocdieui), genital ligula with two thin apico-lateral flagella and abdominal tip (excluding C. lephuocdieui and C. renifera) including appendages yellowish (Asahina 1970, 1984, 1985; Steinhoff & Uhl 2015). Coeliccia lephuocdieui differs from all of the above species by lacking the dorsal yellow marking on its synthorax (Fig. 1a) and combination of the morphological differences in the male appendages and female prothoracic structures. The following comparisons are based on the new species and two Vietnamese species C. scutellum and C. yamasakii apart from C. hainanense which we were not examined. Male of C. lephuocdieui can be easily separated from both C. scutellum and C. yamasakii by following characters: lacking the large oval yellow antehumeral stripe (Fig. 1a); dorsal S10 of C. lephuocdieui black, yellowish latero-ventrally (Fig. 3 a–b) whereas dorsal (in C. yamasakii) or all (in C. scutellum) S10 yellowish (Fig. 3 c–f); cerci of C. lephuocdieui as long as S10, black ventrally, expanding basally, tip acute in lateral view (Fig. 3b) while cerci of C. scutellum clearly longer than S10, entirely yellowish with tip smoothly rounded (Fig. 3 c–d). The new species differs from C. yamasakii by several differential characters: genae and the pattern between eye margin and antennae entirely black (Fig. 5c) but blue in C. yamasakii (Fig. 7b); male synthorax lacking oval spots and the yellow pattern covering most of metepimeron (Fig. 2a) but these spots present in C. yamasakii and yellow pattern covering about posterior 1/3rd of metepimeron (Fig. 7a); genital ligula with the widely apical flap (Fig. 4 a–b) whereas in C. yamasakii, apical portion of terminal segment strongly prominent (Fig. 4 c–d); paraprocts yellowish (Fig. 3b) but dark brownish in C. yamasakii (Fig. 3f). In the female, posterior pronotal lobe of prothorax of C. lephuocdieui well developed (Fig. 6 a–b) but this structure much smaller in C. yamasakii (Fig. 6 e–f); S10 largely yellowish (Fig. 5e) whereas S10 entirely black in C. yamasakii (Fig. 7e).

General body colour of female of C. lephuocdieui same as in C. scutellum, but differs by structural differences of the posterior pronotal lobe of prothorax as follows: in lateral view, this structure is not strongly erect and elongat- ed as C. scutellum (Fig. 6a, c); in dorsal view, posterior pronotal lobe of C. lephuocdieui broadly, triangular-shaped (Fig. 6b) but it is narrower and parallel sided in C. scutellum (Fig. 6d).

Remarks. Coeliccia lephuocdieui and C. scutellum occur at different elevations in the mountain areas of Ayun Commune of Gia Lai Province. The new species occurs at an approximate altitude of 1,500 m compared to about 800–1,000 m for C. scutellum.