Chlorogomphus hoaian, Phan & Karube, 2022

Phan, Quoc Toan & Karube, Haruki, 2022, Description of two new species of the genus Chlorogomphus Selys, 1854 (Odonata: Chlorogomphidae) and a new record of Chlorogomphus gracilis Wilson & Reels, 2001 from the Central Highlands of Vietnam, European Journal of Taxonomy 794 (1), pp. 91-110 : 93-99

publication ID	https://doi.org/ 10.5852/ejt.2022.794.1657
publication LSID	lsid:zoobank.org:pub:55E43CB2-F80D-42AE-839F-8183150C5301
DOI	https://doi.org/10.5281/zenodo.6312438
persistent identifier	https://treatment.plazi.org/id/52E0216D-18F2-4C0A-A7E0-523778EBDFA2
taxon LSID	lsid:zoobank.org:act:52E0216D-18F2-4C0A-A7E0-523778EBDFA2
treatment provided by	Carolina
scientific name	Chlorogomphus hoaian
status	sp. nov.

Treatment

Chlorogomphus hoaian sp. nov.

urn:lsid:zoobank.org:act:52E0216D-18F2-4C0A-A7E0-523778EBDFA2

Figs 1–14 View Figs 1–2 View Figs 3–11 View Figs 12–20 , 21, 24–25 View Figs 21–25. 21–23 , 61 View Figs 61–63

Diagnosis

In lateral view, Chlorogomphus hoaian sp. nov. shows short, robust cerci and an epiproct which are generally similar to those of seven other species: C. aritai , C. arooni Asahina, 1981 , C. caloptera , C. daviesi Karube, 2001 , C. fraseri , C. nakamurai and C. yokoii Karube, 1995 . However, C. hoaian sp. nov. is different from these seven species in major characteristics (alternative characters for the seven other species in parentheses): the cerci ( Figs 12–13 View Figs 12–20 ) are subequal in length to the epiproct (half as long except in C. caloptera ); the dorsoposterior margin of S10 is broadly convex (narrowly convex); the length of the cerci is half that of the epiproct and S10 extends apically (except in C. caloptera , C. arooni ( Asahina 1981: figs 7–8), C. caloptera ( Karube 2013: fig. 6g), C. daviesi ( Karube 2001: figs 5–6) and C. yokoii ( Karube 1995: figs 15–16); the cerci are acute apically ( Fig. 12 View Figs 12–20 ) (blunt apically in C. nakamurai ; see Karube 1995: figs 36–37).

Chlorogomphus hoaian sp. nov. is most similar to C. fraseri and C. aritai by the length of the cerci relative to that of the epiproct. Compared to Chlorogomphus fraseri , the cerci of C. hoaian sp. nov. are triangular in lateral view ( Fig. 12 View Figs 12–20 ), widely separated basally in dorsal view and lack a laterobasal spine ( Fig. 13 View Figs 12–20 ); the epiproct in lateral view is triangular, expanded posteroventrally and armed with a pair of erect inner dorsal projections, separated from each other by a distance greater than the basal width of each projection ( Fig. 13 View Figs 12–20 ) and directed laterally near the apex ( Figs 12–14 View Figs 12–20 ). In C. fraseri , the cerci are broad basally in dorsal view ( Fig. 16 View Figs 12–20 ), abruptly narrowed thereafter, with the apex strongly bent ventrally in lateral view ( Fig. 15 View Figs 12–20 ), abruptly swollen basally medially and laterally in dorsal view ( Fig. 16 View Figs 12–20 ); the bifurcate epiproct in lateral view extends slightly beyond the level of the tip of the cerci; in dorsal view the apex of the epiproct is armed with small teeth dorsally, laterally and apically, with a pair of subbasal, bidentate inner dorsal projections ( Figs 15‒17 View Figs 12–20 ). Although structurally similar, the known ranges of the two species are separated by about 2200 km ( Fig. 63 View Figs 61–63 ).

Compared to those of Chlorogomphus aritai , the male cerci of C. hoaian sp. nov. are armed with a pair of large inner dorsal projections, easily visible in lateral view ( Fig. 12 View Figs 12–20 ), dorsally smoothly concave basally and then slightly convex distally, the apex not pointed in dorsal view and directed posterolaterally ( Fig. 13 View Figs 12–20 ), whereas in C. aritai , the inner dorsal projections are short, not visible in lateral view ( Fig. 18 View Figs 12–20 ) and the cercus is armed laterobasally with a strong acute spine, its apex acute and directed posteriorly ( Fig. 19 View Figs 12–20 ). The epiproct of C. hoaian sp. nov. is widely divaricate, broadly U-shaped ( Fig. 14 View Figs 12–20 ), but in C. aritai , the branches of the epiproct are strongly curved with tips almost touching, forming an incomplete circle ( Fig. 20 View Figs 12–20 ).

The wing pattern in females of Chlorogomphus hoaian sp. nov. is similar to that of C. caloptera ( Figs 21, 23 View Figs 21–25. 21–23 ), but the brownish markings on both wings are less extensive than those in C. aritai ( Fig. 22 View Figs 21–25. 21–23 ). Moreover, the vertex in the female of C. hoaian sp. nov. is armed posteriorly with a well-developed club-like process ( Fig. 25 View Figs 21–25. 21–23 ), somewhat similar to C. aritai ( Karube 2013: fig. 8b 2), while the posterior margin of the vertex is deeply incised in C. caloptera ( Karube 2013: fig. 6b). No specimens of C. fraseri females have been reported.

Etymology

‘ Hoaian ’, named after Mrs Van Cong Hoai An (born 1992) of Da Nang City, Vietnam, the wife of the first author, a noun in apposition.

Material examined

Holotype VIETNAM ‒ Gia Lai Province • ♂; Mang Yang District, Ayun Commune, streams about 2 km from Kon Ka Kinh National Park Headquarters; 14.3672° N, 108.5368° E; alt. 1000 m; 20 Apr. 2019; Q.T. Phan leg.; ZCDTU 2019042001-ODO . GoogleMaps

Paratypes (13 ♂♂, 5 ♀♀) VIETNAM ‒ Gia Lai Province • 1 ♂, 2 ♀♀; same collection data as for holotype; ZCDTU 2019042002-ODO to 2004-ODO GoogleMaps • 7 ♂♂; same locality and collector as for holotype; 20 May 2018; ZCDTU 2018052001-ODO to 2006-ODO GoogleMaps • 4 ♂♂, 1 ♀; same collection data as for preceding; KPMNH 2018052007 to 2011 GoogleMaps • 1 ♀; Ka Bang District, Dak Roong Commune, Dak Trum village ; 14.6845° N, 108.7667° E; alt. 923 m; 24 May 2018; Q.T. Phan leg.; ZCDTU 2018052401-ODO GoogleMaps . ‒ Kon Tum Province • 1 ♂, 1 ♀; Dak Glei District, Dak Man Commune, 2 km from Headquarters of Ngoc Linh Nature Reserve; 15.1471° N, 107.7526° E, alt. 1008 m; 7 Jun. 2019; Q.T. Phan leg.; ZCDTU 2019060701-ODO to 0702-ODO GoogleMaps .

Description

Male ( Figs 1 View Figs 1–2 , 3–4, 7–9 View Figs 3–11 , 12–14 View Figs 12–20 , 24 View Figs 21–25. 21–23 )

MEASUREMENTS. Hw 51 mm long, abdomen (including anal appendages) 55 mm long.

HEAD. Labrum shines black with a small U-shaped yellow marking medially. Anteclypeus black, with lower and upper margins yellow. Postclypeus yellow with lower margin black. Antefrons entirely black. Postfrons black with a large transverse yellow stripe. Distance between eyes 0.7 mm. Antennae

black with pale second segment of anterior part ( Figs 3–4 View Figs 3–11 ). Vertex subtriangular with a longitudinal prominence dorsally ( Fig. 24 View Figs 21–25. 21–23 ). Occiput black, triangular, armed with long setae posteriorly.

THORAX. Prothorax black with anterior margin of anterior pronotal lobe yellow. Synthorax black with a dorsal thin whitish stripe and a narrow antehumeral stripe along lower margin of mesepisternum. Mesepimeron entirely black with a broad, almost parallel-sided yellow stripe covering spiracle; metepimeron black, lined with a narrow yellow stripe on ventral margin. Legs black ( Fig. 1 View Figs 1–2 ).

WINGS. Wings hyaline, brownish at tip. Ax/Px ratio 28/ 16 in Fw and 19/ 17 in Hw. All wings with a median space with 2 crossveins. Anal triangle in Hw with 3 cells. Triangles of all wings with 3 cells, with basal side longer than costal side. In all wings, cubital space with 8–9 crossveins. Anal loop with 16 cells. Pt black, 4.5–5 mm long in all wings, covering 3–3.5 underlying cells ( Fig. 1 View Figs 1–2 ).

ABDOMEN. S1 with a broad oblique stripe, terminating dorsally at end of S2; basal half of S3 yellow and S4–10 black ( Fig. 1 View Figs 1–2 ).

SECONDARY GENITALIA. Anterior lamina in lateral view robust, broad basally, tapering towards apex, strongly petiolate posteriorly. Posterior hamule slender, slightly longer than anterior lamina, curved anteriad ( Fig. 7 View Figs 3–11 ).

VESICA SPERMALIS. With typical shape in genus. Terminal segment with a well-developed lateral keel with a pair of long, curvilinear directed projections at posterior corners. Apical lobes of ventral plate short, hook-like in lateral view. Dorsal part of terminal segment subequal to ventral part. Second segment broad, with a stout spine ( Figs 8–9 View Figs 3–11 ).

ANAL APPENDAGES. Black. Cercus in lateral view shorter than S10, broad basally, tapering toward apex, with tip curved posteroventrally ( Fig. 12 View Figs 12–20 ) and a small lateral projection with long setae apically on distal third. In dorsal view, cerci widely separated at tip, concave subapically ( Fig. 13 View Figs 12–20 ). Epiproct slightly longer than cerci, bearing a pair of large inner dorsal projections, broadly based and tridentate. In lateral view, epiproct expanded apically, dorsal margin serrated apically, inner dorsal projections clearly visible ( Fig. 12 View Figs 12–20 ). In dorsal view, epiproct deeply incised, U-shaped, branches widely separated ( Fig. 14 View Figs 12–20 ). In ventral view, epiproct broad at base, rounded apically ( Fig. 14 View Figs 12–20 ).

Female ( Figs 2 View Figs 1–2 , 5–6, 10–11 View Figs 3–11 , 21, 25 View Figs 21–25. 21–23 )

MEASUREMENTS. Hw 60 mm long, abdomen (including appendages) 56 mm long.

HEAD. As in holotype male, but yellow stripe on postfrons slightly narrower ( Figs 5–6 View Figs 3–11 ) and vertex broadly spherical, with a longitudinal raised area terminating posteriorly as an expanded, club-like prominence ( Fig. 25 View Figs 21–25. 21–23 ). Distance between eyes 1.5 mm.

THORAX AND LEGS. As in holotype male ( Fig. 2 View Figs 1–2 ).

WINGS. Hyaline with black venation. Wing colour pattern tinged with dark golden yellow and patterned as follows: on Fw, brownish band covers space between subcosta to MA vein, runs from base to just beyond nodus, extends from this point, reaching to cubital vein. Wing tip slightly brownish. Hw with a broad, arcuate brown band encompassing most of antenodals (but anterior half of antenodals hyaline), extending posteriorly to wing margin and expanding posteromedially beyond level of triangle, surrounding a large, oval hyaline patch basally. Area between brown band and small darkened mark at wing tip tinged with yellow ( Figs 2 View Figs 1–2 , 21 View Figs 21–25. 21–23 ). Ax/Px ratio 33/ 17 in Fw and 24/ 21 in Hw. Median space with 2 crossveins on all wings. Triangles 4-celled in Fw and 5-celled in Hw. Basal side of triangles of Hw longer than costal side. Cubital space with 10–11 cells in all wings. Anal loop with 26 cells. Pterostigma black, 4.2–4.5 mm long on all wings, covering 3.5–4 underlying cells.

ABDOMEN. Abdominal pattern as in holotype male, but yellow pattern slightly more extensive. S4–5 mostly black with a yellow spot at anterior margin. Yellow spot on S5 small. S6–10 entirely black ( Fig. 2 View Figs 1–2 ).

CERCI. Entirely black, narrow. Length ⅓ that of S10 ( Fig. 10 View Figs 3–11 ). Valvula valvae trapezoidal-shaped, as shown in Fig. 11 View Figs 3–11 . Ventral projection of S10 reaches slightly beyond equal cerci ( Fig. 10 View Figs 3–11 ).

Morphological variation in paratypes

MEASUREMENT VARIATION. Males: Hw 52–53 mm long, abdomen (including anal appendages) 52–56 mm long. Females: Hw 57–58 mm long, abdomen (including appendages) 55–58 mm long.

WING VENATION. Males: Ax/Px ratio 26–29/ 14–16 in Fw and 19–23/ 16–17 in Hw. Cubital space with 8–9 crossveins in all wings. Anal loop 15–17-celled. Females: Ax/Px ratio 31–33/ 17–18 in Fw and 22–25/ 21 in Hw. Triangles of all wings 4–5-celled. Cubital space with 10–11 cells in all wings. Anal loop with 25–26 cells.

OTHER CHARACTERS. The S 4 in a male from Ngoc Linh Nature Reserve has a tiny yellow spot at the anterior end (entirely black in the holotype and other male specimens). The width of the brown band on Hw of the female specimens from Ngoc Linh (ZCDTU 2019060701-ODO and 0702-ODO) and Dak Trum (ZCDTU 2018052401-ODO) are much narrower than in specimens from the type locality.

Distribution

Vietnam ( Fig. 61 View Figs 61–63 : yellow circle): Kon Tum Province (Dak Glei District) and Gia Lai Province (Mang Yang District and Ka Bang District).

Habitat and ecology

The new species was discovered coursing up and down over small streams (2–4 m width) interspersed with large stones within dense vegetation in a pristine forest. No other specimens of Chlorogomphus were found at the type locality.