Gelastyrella vuquangensis, Constant & Pham & Nguyen, 2025

Gelastyrella vuquangensis sp. nov.

Figs 1 View Figure 1 , 2 View Figure 2 , 3 View Figure 3 , 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8

Type material.

Holotype ♂, Vietnam • Ha Tinh Province, Vu Quang National Park., near Khe Chè station ; 18°22'38"N, 105°18'41"E; 13–15 Jul. 2023; J. Constant, J. Bresseel and L. Semeraro leg.; I. G.: 34.661; RBINS GoogleMaps .

Paratypes, Vietnam • 8 ♂♂, 15 ♀♀; same data as for holotype; RBINS GoogleMaps • 8 ♂♂, 2 ♀♀; Ha Tinh Province, Vu Quang National Park, near Khe Chè station ; 18°22'38"N, 105°18'41"E; 13–15 Jul. 2023; Trung T. Vu and Hoai T. T. Nguyen leg.; VNMN -E.000.016.100 - VNMN -E.000.016.109 ; VNMN GoogleMaps .

Diagnosis.

The species is externally rather similar to G. litaoensis Yang, 1994 (see illustrations in Constant and Pham 2024 b: figs 19–21) but it is shorter (on average, ♂: 6.8 mm, ♀: 7.4) than the Vietnamese specimens of G. litaoensis (on average, ♂: 8.1 mm, ♀: 8.9), and it is generally paler than G. litaoensis ; it shows gonostyli with a short posterior lobe and a short, wide capitulum in lateral view (lobe and capitulum elongate in G. litaoensis ); the periandrium of the male shows moderately developed basiventral lobes (lobes massive, strongly projecting anteriad in G. litaoensis ); the lateroventral processes of the aedeagus are strongly curved mesad in distal portion, ventrally overlapping (more or less parallel in G. litaoensis ); the process of sternite VII of females is apically emarginate in middle (rounded in G. litaoensis ).

Description.

Measurements and ratios: LT: ♂ ( n = 9): 6.8 mm (6.6–7.2); ♀ ( n = 9): 7.4 (7.2–7.5). LT / BB = 1.6; LTg / BTg = 2.1; LW / BW = 1.5; LV / BV = 0.5; LF / BF = 1.0.

Head (Figs 1 A – D View Figure 1 , 2 A – D View Figure 2 ): vertex variegated brown, about twice as broad as long in midline, with all margins carinate; anterior and posterior margins distinctly curved, subparallel; lateral margins weakly curved, subparallel; disc excavate with obsolete median carina. Side of head yellowish with darker area between anteroventral portion of eye and anterior margin; anteroventral angle weakly projecting anteriorly. Frons appearing weakly elongate and generally smooth, variegated brown (darker than vertex) with blackish dorsal line between dorsal margin and distinct subdorsal transverse carina; median carina extending from dorsal margin down to rounded frontoclypeal suture; dorsal margin concave, lateral margins distinctly sinuate. Clypeus variegated dark brown with paler median line (more or less distinct), weakly elevated medially. Labium brown with last segment longer than broad, and shorter than penultimate. Antennae dark brown; scape short, ring-shaped; pedicel subcylindrical.

Thorax (Figs 1 A, C, D View Figure 1 , 2 A – D View Figure 2 ): pronotum variegated yellowish to greenish brown; about 0.6 times as long as mesonotum in midline; anterior margin carinate, moderately, roundly protruding anteriorly between eyes; posterior margin curved, raised; no median carina but with impressed point on each side of median line; lateral portion behind eye very narrow, laminate; blunt, pale yellowish tubercles scattered on outer margin of paranotal lobes; paranotal lobes broad, brown in outer portion, pale yellowish in inner portion and with darker marking under eye, and with posteroventral angle rounded. Mesonotum variegated yellowish to or greenish brown without distinct carinae; smooth, slightly depressed before scutellum. Tegulae yellowish to greenish brown.

Tegmina (Figs 1 A – D View Figure 1 , 6 View Figure 6 ): variegated yellowish to or greenish brown with irregular brown markings (more developed in females), usually covered in fine pruinous wax in live specimens; subcoriaceous with longitudinal veins slightly darker than background, elevated and with a dense reticulum of weak pale yellow veinlets; shape elongate and convex, about 2.1 times as long as broad with sides broadly rounded, widest at basal 1 / 3; tapering towards narrowly rounded apex. Postclaval margin nearly straight on most length, weakly notched at apex of clavus. Epipleuron present, moderate. Clavus closed, reaching 2 / 3 of length of tegmen.

Venation: ScP + R forking close to base after rather short common stem, ScP + RA and RP running more or less parallel to costal margin and not forked; MP forked after moderate common stem, resulting vein MP 1 forked again further; CuA simple, sinuate, more or less parallel to claval joint, then to sutural margin and merging with latter before apex of tegmen; Pcu and A 1 fused at slightly beyond 2 / 3 of clavus, resulting Pcu + A 1 reaching apex of clavus.

Hind wings (Fig. 2 E View Figure 2 ): yellow-brown with distal portion of lobes Sc-R-MP-CuA and CuP-Pcu-A 1, and lobe A 2 darker brown; venation darker than corresponding background; wing deeply bilobed at CuP; costal margin distinctly bisinuate; CuP-Pcu-A 1 lobe broadly rounded along postclaval margin and about as wide as Sc-R-MP-CuA lobe; both lobes approximately the same length, angularly rounded at apex; A 2 lobe narrow. Venation: longitudinal veins ScP-R-MP-Cu well distinct; Pcu and A 1 separated; numerous cross-veins; cross-veins delimiting large cells between Pcu and A 1; A 2 lobe narrow.

Legs (Fig. 1 A – F View Figure 1 ): rather elongate and slender, yellowish to greenish brown with metafemora, pro- and mesotarsi, and spines of hind legs, dark brown; posterior margin of pro- and mesofemora with row of acute minute teeth. Metatibiae with 2 lateral spines in distal half and 8 apical spines. First segment of metatarsus with strong tooth on each side, and large ventral pad of microspines in distal portion. Metatibiotarsal formula: (2) 8 / 2 ++ / 2.

Abdomen (Fig. 1 B View Figure 1 ): yellowish to greenish with wide, darker band in middle.

Terminalia ♂ (Figs 3 View Figure 3 – 5 View Figure 5 ): pygofer (Fig. 3 A, E – G View Figure 3 ) about 2.0 times as high as long in lateral view (widest in ventral portion), with anterior margin incurved in dorsal portion and posterior margin more or less straight up to dorsal lobe directed caudad; posterior margin dorsally deeply excavate (U-shaped excavation wider towards base). Gonostyli (Fig. 3 B – D, H View Figure 3 ) in lateral view, rather short and robust, subtriangular, produced caudad in a short lobe rounded apically, and moderately concave; capitulum massive, with rather short and wide neck, spiralling up with lateral, more or less oblique, laminate projection, and apex ended in oblique lamina directed cephalo-dorsomesad. Anal tube (Fig. 3 A, E – G View Figure 3 ) racket-shaped in dorsal view, more or less dorsoventrally flattened, with basal narrow shaft representing 3 / 5 of length, nearly 2.4 times as long in midline as wide (widest point in distal portion); distal rounded portion starting at anal opening, convex with all margins downcurved; apical margin with round ventral emargination in caudal view. Aedeagus (Figs 4 View Figure 4 , 5 View Figure 5 ) symmetrical, strongly recurved dorsad (in lateral view), with massive suspensorium consisting of large, boomerang-shaped lateral parts linked by wide, flat connective in distal portion (connective placed under aedeagus ss). Periandrium (Figs 4 View Figure 4 , 5 A – G View Figure 5 ) complex, basally with moderately developed lobes projecting ventrad, ventral lobe rather simple, apically rounded, shorter than dorsal lobe; dorsal lobe in distal portion with lateral (external) arm-shaped processes directed cephalad and apically bifid, mesolateral laminate processes projecting cephalad with anterior margin sinuate and dorsal angle pointed; terminal portion mobile, articulated, at rest covering subapical processes of aedeagus ss, strongly curved in lateral view, anterior portion with two oblique laminae projecting laterodorsad (small teeth on inner wall), posterior portion upcurved, ended in elongate, apically rounded process (in lateral aspect), subtriangular in caudal view. Aedeagus ss (Fig. 5 H – L View Figure 5 ) elongate, curved in lateral view, bifid along distal 2 / 3; subapical strong, upcurved dorsal process on each shaft, slightly directed mesad in dorsal view; lateroventral processes strong, directed anteroventrad in lateral view; in (postero) ventral view, sinuate in basal portion, then strongly curved mesad (rounded right angle) and tapering to narrow point (distal portion overlapping ventrally). Connective (Fig. 4 A – F View Figure 4 ) well developed, elongate, curved, with massive tectiductus, more or less compressed laterally with large foramen.

Terminalia ♀ (Fig. 2 F View Figure 2 ): hind margin of sternum VII with large process directed caudad, with lateral margins curved and posterior margin distinctly emarginate in middle.

Etymology.

The species epithet refers to Vu Quang National Park in Ha Tinh Province, where the new species was discovered.

Biology.

The specimens were found sitting on tree trunks and larger branches covered in moss and lichen (Figs 6 View Figure 6 , 7 View Figure 7 ). Their colouration makes them very cryptic and difficult to spot in their habitat, and the insects seem very confident in their protection strategy, as they often will not move until touched. Despite the exceptionally dry conditions in July 2023, the species was rather common around Ke Chè station.

Distribution.

Vietnam, Ha Tinh Province, Vu Quang National Park (Fig. 8 View Figure 8 ).