Hemisphaerius thaydoius, Constant & Pham, 2025

Constant, Jérôme & Pham, Hong Thai, 2025, Issid planthoppers from Bach Ma and Phong Dien in Central Vietnam: (II) Tribe Hemisphaeriini (Hemiptera: Fulgoromorpha: Issidae), European Journal of Taxonomy 994 (1), pp. 1-76 : 33-40

Hemisphaerius thaydoius sp. nov.

urn:lsid:zoobank.org:act:6FDB7F3D-396B-409A-8617-0C38E95C3D8E

Figs 2A , 3A , 18–22

Diagnosis

Hemisphaerius thaydoius sp. nov. varies in body colour from nearly entirely orange with or without turquoise markings on frons, pro- and mesonotum, and with or without irregular (but symmetrical) brown markings on tegmina, to creamy yellow with large black markings or even to entirely blackish brown ( Figs 18–19 , 21 ), but can be recognized by:

(1) the black band along the ventral margin of the paranotal lobes of the prothorax ( Fig. 18D–E , 19D– E );

(2) the shape of the anal tube, subtriangular with apical margin weakly convex in dorsal view, and with posterolateral angles weakly developed and weakly projecting lateroventrad (An – Fig. 20A–D );

(3) the strongly posterodorsally curved at a distinct obtuse angle lateral aspect of the aedeagus ( Fig. 20I–J );

(4) the left lateral lobe of the periandrium being distinctly larger and projecting further posteriorly than the right one, the outer lateral margin with an elongate, subtriangular process curved anteromesad and a rounded externodorsal lobe followed by a strong spinose process oblique in posterior view and directed cephalodorsad ( Fig. 20E–L );

(5) the right lateral lobe of the periandrium with the outer margin more or less rounded, the dorsal inner angle projecting as a curved tooth directed mesocephalad, hidden by the left lobe in caudal view ( Fig. 20E–H ).

Differential diagnosis

The closest species are H. hippocrepis Constant & Pham, 2011 and H. rufovarius Walker, 1858 . However, H. thaydoius sp. nov. differs from H. hippocrepis by having a subtriangular anal tube in dorsal view ( Fig. 20D ), while it is suboval and apically truncate in H. hippocrepis ( Constant & Pham 2011: fig. 8) and by the left lateral lobe of the periandrium with the outer lateral margin with an elongate, subtriangular process curved anteromesad and a rounded externodorsal lobe followed by a strong spinose process, oblique in posterior view ( Fig. 20 E–J ), while it shows a wide, apically rounded lobe curved cephalodorsad and a much shorter spine in H. hippocrepis ( Constant & Pham 2011: figs 11–13); from H. rufovarius , it differs by the absence of a ventral spine on the anal tube ( Fig. 20A ), while H. rufovarius shows a very distinct one ( Constant & Pham 2024a: fig. 12a) and by the triangular and rounded laminate lobes on the left lobe of the periandrium as described above ( Fig. 20E–J ), while no such lobes are visible in H. rufovarius ( Constant & Pham 2024a: fig. 12e–h).

Etymology

The species epithet thaydoius is derived from the Vietnamese phrase ‘thay đổi’, meaning ‘changing, variable’. It refers to the highly variable colouration of this species.

Material examined

Holotype VIETNAM • ♂ (dissected); Thừa Thiên-Huế Province, Phong Dien District; 16°30′27″ N, 107°16′05″ E; 350–400 m a.s.l.; 23 May 2023; J. Constant and L. Semeraro leg.; I.G.: 34.640; VNMN.

Paratypes VIETNAM • 2 ♀♀; same collecting data as for holotype; VNMN • 1 ♂, 3 ♀♀; same collecting data as for holotype; RBINS • 1 ♂, 1 ♀; Thừa Thiên-Huế Province, Bach Ma National Park , [pheasant trail]; 16°12′ N, 107°52′ E; 10–16 Apr. 2017; [500–600 m a.s.l.]; J. Constant and J. Bresseel leg.; I.G.: 33.447; RBINS • 1 ♂, 1 ♀; Thừa Thiên-Huế Province, A Luoi, A Roang ; [16°07′04″ N, 107°24′19″ E]; 600–700 m a.s.l.; 4 May 2005; H.T. Pham leg.; Ho.1585, 1589; VNMN • 1 ♂, 1 ♀; Thừa Thiên-Huế Prov., Bach Ma National Park, ranger station , Nam Dong District; 16°08′37″ N, 107°49′36″ E; 150–500 m a.s.l.; 19 Oct. 2024; J. Constant, L. Semeraro and Hoai T.T. Nguyen leg.; I.G.: 34.893; RBINS • 1 ♀; same collection data as for preceding; VNMN • 1 ♀; Thừa Thiên-Huế Province, Bach Ma National Park, near ranger station ; 16°08′37″ N, 107°49′36″ E; 300–600 m a.s.l.; 18 May 2023; J. Constant and L. Semeraro leg.; I.G.: 34.640; RBINS • 2 ♀♀; same collection data as for preceding; VNMN • 1 ♂; Quang Tri Province, Huong Hoa, Huong Phung, Deo Sa Mu ; [16°48′00″ N, 106°35′10″ E]; 900–1000 m a.s.l.; 4 Jun. 2006; H.T. Pham leg.; VNMN • 1 ♂; Ha Tinh Province, Vu Quang National Park, near Khe Chè station ; 18°22′38″ N, 105°18′41″ E; 13–15 Jul. 2023; V.T. Trung and N.T.T. Hoai leg.; VNMN • 1 ♂, 2 ♀♀; same data as for preceding; J. Constant, J. Bresseel and L. Semeraro leg.; I.G.: 34.661; RBINS .

Description

Note: The bright colour of the live specimens ( Fig. 21 ) tends to fade in collection specimens, with the turquoise colour of the markings on the thorax and head turning to yellow and the rest of the body, in the paler forms, tending to become more yellowish as well.

MEASUREMENTS AND RATIOS. LT: ♂ (n = 4): 4.7 mm (4.5–4.8), ♀ (n = 5): 4.8 mm (4.2–5.0); LT/BB = 1.49; LTg/BTg = 1.52; LW/BW = 1.76; BV/LV = 3.88; LF/BF = 0.87.

HEAD ( Figs 18A–E , 19A–E , 21A–G ). Vertex strongly broader than long in midline, orange to dark brown, flattish with weak median carina, sometimes obsolete, and lateral and posterior margins weakly carinate; anterior margin weakly curved, posterior one concave and lateral ones sinuate, converging cephalad. Side of head yellowish orange to reddish brown, paler under antennae. Frons convex, slightly elongate and weakly rugulose, widest under antennae, orange to reddish brown with large darker area in middle, to entirely blackish brown; orange specimens often with turquoise marking at dorsolateral angles; no carina; frontoclypeal suture marked by a transverse pale yellow band. Clypeus black with basilateral pale yellow marking prolongating band on frontoclyeal suture, convex, smooth. Labium yellow brown with last segment longer than broad, about as long as penultimate one. Antennae yellow-brown; scape short, ring-shaped; pedicel bulbous.

THORAX ( Figs 18A–E , 19A–E , 21A–G ). Pronotum orange, often with 2 subtriangular turquoise markings on disc, to entirely blackish brown; very short, about ⅓ length of mesonotum in midline, extremely narrow behind eyes, without median carina, with fine carinae along anterior and posterior margins; disc with small, impressed point on each side of median line; paranotal lobes paler than dorsum and with distinct black band along ventral margin. Mesonotum orange, often with median turquoise line not reaching anterior margin and triangular turquoise marking on lateral angles, to entirely blackish brown; rather short, weakly rugulose with fine transverse carina along anterior margin but without longitudinal carinae. Tegulae coloured as tegmina, orange to blackish brown.

TEGMINA ( Figs 18A, C , 19A, C , 21A–G ). Colour variable, from entirely orange to orange, orangish testaceous or creamy yellow with irregular but symmetrical brown markings (often with transverse band at ¾ of total length), to entirely blackish brown; strongly convex, rugulose; about 1.2 times as long as broad when taken together in dorsal view; costal margin broadly rounded, apical margin rounded; venation obsolete.

HIND WINGS ( Figs 18F , 19F ). Brown with basal portion suffused with red and veins slightly darker; strongly reduced, curved and widening from base to ⅘ of length. Veins indistinct on basal ⅓, reticulate on remaining portion.

LEGS ( Figs 18A–E , 19A–E ). Elongate and moderately slender, yellowish brown; all tarsi with black-brown onychium; pro- and mesofemora slightly wider than corresponding tibiae; coxae, trochanters and basal ¾ of metafemora (at least partly) dark brown; in dark forms, distal portion of pro- and mesotibiae dark brown; apex of metatibial spines and metatarsal spines black-brown. Metatibiae with 2 lateral spines on apical ⅓ and 6 apical spines. Metatarsi short with first segment about as long as combined length of remaining segments. Metatibiotarsal formula: (2) 6/ 8–9 / 2.

ABDOMEN ( Figs 18B , 19B ). Sternites yellowish, turning brown along posterior margin, to dark brown.

MALE TERMINALIA ( Fig. 20 ). Pygofer (Py – Fig. 20A–D ) about 2.6 times as high as long at midheight in lateral view, with posterior margin projecting posterad into a round lobe in dorsal ⅔, then sinuate in ventral ⅓ in lateral view; subcircular in caudal view. Gonostyli (G – Fig. 20A–D ) convex, suboval in lateral view (without capitulum), with dorsal margin weakly sinuate and ventroapical margin strongly rounded, with an emargination at base of capitulum; capitulum (ca) with short and wide neck in lateral view, projecting dorsomesad, with dorsal tooth curved anteromesad and lateral slightly laminate tooth curved lateroventrad. Anal tube (An – Fig. 20A–D ) dorsoventrally flattened, rather short, subtriangular, slightly wider than long in midline and with anal opening at about basal ⅓; small hump on ventral side, at around half length; lateral margins weakly sinuate, more or less evenly diverging and posterior margin weakly convex in large middle portion in dorsal view; dorsal margin straight with apicodorsal angle straight and ventral margin slightly curved ventrad in lateral view; apical angles weakly produced lateroventrad; apical margin weakly curved in caudal view. Aedeagus ( Fig. 20E–N ) asymmetrical, strongly curved, slightly twisted, reflexed dorsad at distinct obtuse angle slightly beyond midlength in lateral view. Ventral lobe of periandrium (vl) laminate, moderately lanceolate apically, projecting on right side between lateral lobes and shorter than these lobes ( Fig. 20E–G ). Lateral lobes of periandrium (ll) laminate and longitudinally twisted, with left lobe distinctly larger and projecting further posteriorly than right one; left lobe with outer lateral margin with elongate, subtriangular process curved anteromesad and rounded externodorsal lobe followed by strong spinose process, oblique in posterior view and directed cephalodorsad, inner margin strongly sinuate under tooth; right lobe with outer margin more or less rounded, dorsal inner angle projecting as curved tooth directed mesocephalad, hidden by left lobe in caudal view. Connective (co – Fig. 20I–J ) strongly developed, corpus connective long and regularly curved in lateral view, tectiductus (te) strongly developed, curved, conical, with wide anterior foramen and with crista visible as a weak carina.

Biology

Hemisphaerius thaydoius sp. nov. was collected in April, May, June, July and October at altitudes between 150 and 700 m a.s.l., in moist evergreen tropical forest. The specimens were sitting on lower vegetation and bushes on small branches, and more often on leaves, and seemed to prefer smooth leaves. In Bach Ma National Park it was found at the collecting sites/habitats “pheasant trail” ( Figs 2A (2), 3A) and “ranger station” ( Figs 2A (6), 5A). It was also collected in Phong Dien District, not far from a stream ( Figs 5B , 21H ).

Distribution

Vietnam: Thừa Thiên-Huế Province (Bach Ma National Park, Phong Dien District, A Roang), Quang Tri Province (Deo Sa Mu) and Ha Tinh Province (Vu Quang National Park) ( Fig. 22 ).

Figures

Fig. 2. Bach Ma National Park, habitats. A. Detailed map of the sampling areas (1 = ‘Yes Hue Eco’; 2 = ‘pheasant trail’; 3 = ‘low altitude’; 4 = ‘roadside’; 5 = ‘summit’; 6 = ‘near ranger station’. B. Typical habitat at ‘Yes Hue Eco’ sampling area, 17 May 2023.

Fig. 3. Bach Ma National Park, habitats. A. Typical habitat at ‘pheasant trail’ sampling area, 20 May 2023. B. Typical habitat at ‘low altitude’ sampling area, 15 May 2023.

Fig. 18. Hemisphaerius thaydoius sp. nov., dissected holotype, ♂ (VNMN). A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Habitus, perpendicular view of frons. E. Habitus, anterolateral view. F. Right hind wing.

Fig. 19. Hemisphaerius thaydoius sp. nov., dissected paratype, ♂, black morph, from Bach Ma National Park (RBINS). A. Habitus, dorsal view. B. Habitus, ventral view. C. Habitus, lateral view. D. Habitus, perpendicular view of frons. E. Habitus, anterolateral view. F. Right hind wing. G. Left hind leg, ventral view. H. Metatarsus and apex of metatibia, ventral view.

Fig. 20. Hemisphaerius thaydoius sp. nov., dissected holotype, ♂ (VNMN), terminalia. A–D. Pygofer, anal tube and gonostyli. A. Left lateral view. B. Posterolateral view. C. Caudal view. D. Dorsal view. E–N.Aedeagus.E. Left posterolateral view.F. Caudal view.G. Right posterolateral view.H.Anterodorsal view. I. Left lateral view. J. Right lateral view. K. Left laterodorsal view. L. Right laterodorsal view. M. Dorsal view. N. Ventral view. Abbreviations: see Material and methods.

Fig. 21. Hemisphaerius thaydoius sp. nov. A–B. Live specimen in Bach Ma National Park, pheasant trail, 12 May 2023.C–D. Bach Ma National Park, near ranger station. C. 18 May 2023. D. 19 Oct. 2024 (photographed in cage). E–H. Phong Dien District, 23 May 2023. E–G. Specimen. H. Microhabitat.

Fig. 22. Hemisphaerius thaydoius sp. nov., distribution map.

Fig. 5. Bach Ma National Park and Phong Dien District, habitats. A. Typical habitat at ‘ranger station’ sampling area, 18 May 2023. B. Typical habitat at Phong Dien sampling area, 23 May 2023.