Gergithoides olivaceus, Constant & Pham, 2024

Constant, Jérôme & Pham, Hong Thai, 2024, Sixteen issid planthopper species in one day in Dong Son-Ky Thuong Nature Reserve in North Vietnam: Eight new species, one new genus and additional new records (Hemiptera: Fulgoromorpha: Issidae), European Journal of Taxonomy 919 (1), pp. 1-87 : 7-11

Gergithoides olivaceus sp. nov.

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Figs 1 , 3–4

Diagnosis

Gergithoides olivaceus sp. nov. can be recognized by

(1) the shape of the lateroventral bispinose process of the periandrium with anterior spine strongly elongate cephalad, weakly curved, then sinuate in distal portion and pointed apically and posterior spine directed posterodorsad along basal half, then strongly but evenly recurved ventrad and tapering to pointed apex (lvp – Fig. 4E–F );

(2) the ventral lobe of the periandrium with dorsal margin broadly rounded, nearly truncate (vl – Fig. 4G );

(3) the median posterior processes of periandrium pointed apically and laterally emarginate subapically ( Fig. 4G ).

Differential diagnosis

The closest species, sharing the character of a bispinose lateroventral process of the periandrium with anterior spine elongate and posterior spine curved, are G. carinatifrons described from Taiwan ( Schumacher 1915) and G. undulatus described from Hainan and Guangxi ( Che et al. 2003).

From both G. carinatifrons (illustrations in Chan & Yang 1994: fig. 5) and G. undulatus (illustrations in Che et al. 2003: figs 1–6), G. olivaceus sp. nov. can be separated by its apically sinuate anterior spine of the lateroventral process of the periandrium (evenly curved dorsad in G. carinatifrons and G. undulatus ) and the evenly rounded hook formed by the posterior spine of the periandrium process (strongly, abruptly reflexed in G. carinatifrons and G. undulatus ).

Etymology

The species epithet olivaceus is a Latin adjective meaning ‘olive-green’. It refers to the general colour of the specimens of the new species.

Type material

Holotype

VIETNAM • ♂ (dissected, right hind wing mounted, Figs 3–4 ); Quang Ninh Province, Dong Son-Ky Thuong Nature Reserve ; 21°08′29″ N, 107°04′53″ E; 27 Aug. 2022; 550 m a.s.l.; secondary forest; GTI Project; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.518; RBINS.

Paratypes

VIETNAM • 1 ♀; same collection data as for holotype; RBINS • 1 ♀; same collection data as for holotype; VNMN .

Description

MEASUREMENTS AND RATIOS. LT: ♂ (n = 1): 5.6 mm, ♀ (n = 2): 6.0– 6.4 mm; LT/BB = 1.34; LTg/BTg = 1.67; LW/BW = 1.9; BV/LV = 0.8; LF/BF = 1.27.

HEAD ( Fig. 3A–D ). Vertex slightly longer in midline than broad, brown with margins carinate; anterior margin convex, posterior one concave and lateral converging anteriorly; disc excavate with obsolete tubercles. Side of head yellowish brown. Frons elongate and rugulose, dark reddish brown; median carina yellowish, narrowly margined with a black line, extending from dorsal margin down to frontoclypeal suture; row of yellowish tubercles on black background along dorsal and lateral margins extending to level of base of eyes; lateral margins yellowish under eyes, the yellowish line marginated by inner thin black line. Clypeus black-brown with basilateral yellowish spot and black on sides and apex, elevated medially. Labium dark brown with last segment longer than broad, and shorter than penultimate. Scape short, ring-shaped, black; pedicel bulbous, dark brown.

THORAX ( Fig. 3A–D ). Variegated olivaceous brown. Pronotum very short, about half the length of mesonotum in midline, with median carina; anterior and posterior margins carinate; disc rugulose, concave with impressed point on each side of median carina; row of yellowish tubercles along anterior margin extending on paranotal fields to level of base of eyes; another oblique row of 3 weak yellowish tubercles on each side of disc, parallel to anterior margin. Mesonotum short, slightly coriaceous with yellowish median carina and obsolete impressed point on each side of disc; transverse carina along anterior margin yellowish; 2–4 yellowish blunt tubercles grouped at each external angle; yellowish suffused marking on each side of scutellum; apex of scutellum elevated and marked with dark brown. Tegulae olivaceous.

TEGMINA ( Fig. 3A, C ). Strongly convex; slightly longer than broad when taken together in dorsal view; slightly concave at basocostal angle; subcoriaceous with dense reticulum of slightly raised veins and veinlets; mains veins barely distinct basally; yellowish brown with brown to black irregular markings, especially along inner margin of cells, making the insect look olivaceous from a distance; small darker spot in middle of sutural margin.

HIND WINGS ( Fig. 3E ). Brown, with costal half suffused with blackish, except basicostal angle, unilobed, with veins darker than cells; elongate, slightly shorter than tegmina. Venation reticulate with main longitudinal veins distinct basally (C, ScP+R, MP, CuA); numerous cross-veinlets. Anal area obsolete. Costal and cubital margins sinuate, distal margin rounded.

LEGS ( Fig. 3A–D ). Elongate and slender, brown with trochanters, base of femora, line along externoventral margin of femora, black; black-brown line on ventral carinae of tibiae; base and apex of tibiae, apex of tarsi and apex of metatibial spines black-brown; pro- and mesofemora with pale yellow tubercles. Posterior tibiae with 2 lateral spines on apical ⅓ and 6 apical spines. Metatibiotarsal formula: (2) 6 / 8–9 / 2.

ABDOMEN ( Fig. 3B ). Brown with middle and posterior area darker, often with irregular paler markings on sides of sternites.

MALE TERMINALIA. Pygofer (Py) 2.2 times as high as broad in lateral view, with posterior margin strongly sinuate, rounded along dorsal ⅔ ( Fig. 4A–B ); ventral margin rounded in lateral view ( Fig. 4A–B ). Gonostyli (G – Fig. 4A–B, D ) elongate in lateral view, with ventral margin broadly rounded in lateral view, posterior margin more narrowly rounded in lateral view, dorsal margin oblique basally to neck of capitulum, more posteriorly forming a straight angle with neck of capitulum; capitulum (ca) with elongate neck, curved dorsocephalad in lateral view, mesad in posterior view, with small blunt lateral projection in middle of outer margin; apical portion anteroposteriorly laminate, subrectangular in caudal view, bearing one dorsal tooth, one tooth at inner angle and one tooth pointing anteroventrally at anterobasal, followed posterad by a lateral lamina curved ventrad looking like an additional tooth in caudal view.Anal tube (An – Fig. 4A–C ) nearly as broad as long in midline in dorsal view, dorsoventrally flattened with sides sinuate, diverging towards apex, apical margin weakly bisinuate in dorsal view; in lateral view, anal tube curved ventrally; apicolateral angles roundly projecting lateroventrally. Aedeagus strongly curved posterodorsally, rather simple ( Fig. 4E–I ). Periandrium with lateroventral process (lvp) at basal half showing 2 spines; anterior spine strongly elongate cephalad, weakly curved, more or less parallel to ventral margin of aedeagus, sinuate in distal portion and pointed apically; posterior spine directed posterodorsad, forming a nearly right angle with anterior spine, slightly widening along basal half, then strongly recurved ventrad and tapering to pointed apex ( Fig. 4E–F ); periandrium with laminate process reflexed cephalad on each side in distal portion, with right one slightly more developed and projecting slightly further laterally than left one ( Fig. 4E–F, I ) and 2 median processes pointed apically and with lateral margin sinuate anteapically ( Fig. 4G ). Ventral lobe of periandrium (vl) broad with apical margin roundly truncate ( Fig. 4G ).

Biology

Gergithoides olivaceus sp. nov. was collected in August on lower vegetation and bushes, in moist evergreen tropical forest at about 550 m in altitude ( Fig. 1B ).

Distribution

Vietnam: Quang Ninh Province, Dong Son-Ky Thuong Nature Reserve ( Fig. 1A ).

Figures

Fig. 1. Dong Son-Ky Thuong Nature Reserve. A. Topographic map. B. Sampled habitat.

Fig. 3. Gergithoides olivaceus sp. nov., dissected holotype, ♂ (RBINS). A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Habitus, perpendicular view of frons. E. Right hind wing.

Fig. 4. Gergithoides olivaceus sp. nov., holotype, ♂ (RBINS), terminalia. A–D. Pygofer, anal tube and gonostyli. A. Left lateral view. B. Anterolateral view, showing apex of capitulum. C. Dorsal view. D. Caudal view. E–I. Aedeagus and connective. E. Left lateral view. F. Right lateral view. G. Posteroventral view. H. Ventral view. I. Anterodorsal view. Abbreviations: see Material and methods.