Leucodellus Reuter, 1906

Konstantinov, Fedor V., 2012, Leucodellus Reuter, 1906 (Heteroptera: Miridae: Phylini): key to species, revised species composition and diagnosis, Zootaxa 3157, pp. 18-30 : 19-20

Leucodellus Reuter, 1906

Type species by monotypy: Leucodellus albidus Reuter 1906: 69 .

Heterochlorillus Putshkov, 1970: 752; synonymized by Li & Liu 2007: 34. Leucophylus Duwal, Yasunaga & Lee 2010: 23; new synonymy.

Revised diagnosis. Distinguished by the following characters of the male and female genitalia: male genital segment exceptionally large, 0.6–0.7 of abdomen ( Fig. 3 ), equal to or longer than combined length of head and pronotum; right paramere lanceolate; vesica strongly coiled, with several closely approximating sclerotized ridges running along margin of lateral strap, apically with two characteristically shaped blades, small blade more or less twisted along axis and attenuated laterally, large blade long and thin, gradually curved ( Figs. 12–17 ); secondary gonopore with well developed sculpture and long and distinct gonopore sclerite, far removed from apex of vesica, placed on membranous, dentate lobe; sclerotized rings of female dorsal labiate plate almost triangular, with distinctly tapering anterior angles ( Fig. 22 ). Body form elongate and nearly parallel-sided, length 3.2–4.8 male, 3.0– 5.0 female. Coloration almost completely pale, hemelytra sometimes with pale brown markings, usually with dark markings on femora, brown spot at base of hind tibia and darkened bases of tibial spines. Vestiture with reclining pale simple setae only, rarely somewhat darkened on cuneus.

Similar in size and body proportions, general appearance including dark pattern on legs, and twin bladed vesica with approximating ridges on lateral strap to pale-colored species of Plagiognathus Fieber, 1858 (see Schuh 2001), Europiella Reuter, 1909 (see Schuh 2004), Chlorillus Kerzhner, 1962 (see Wagner 1975), Phaeochiton Kerzhner, 1964 (see Konstantinov 2008), and Atraphaxis -feeding group of Glaucopterum Wagner, 1963 (see Kerzhner 1984; Konstantinov 2006, 2011). Clearly distinguished from these genera by the distinctive curvature of the vesica and the shape of its apical blades, presence of the large gonopore sclerite, and triangular sclerotized rings of dorsal labiate plate. Further differing from Europiella and Glaucopterum in having lanceolate, not truncated right paramere, and from Europiella , Chlorillus , and Phaeochiton in lacking of silvery flattened and dark simple setae on dorsum.

Redescription. Male. Macropterous, with elongate body, total length 3.3–4.7.

COLORATION: Uniformly pale greenish to pale whitish in life, yellowish to white in collections, dorsum uniformly pale, rarely hemelytron with scarce minute brown spots or diffuse and indistinctly bordered pale brown markings, membrane whitish, semitransparent, typically with oblique wedge-shaped macula at base and variously shaped diffuse paler brown markings behind cells ( Figs. 1, 2, 5 ); fore and middle femora with faint minute brown spots apically, rarely uniformly pale, apex of hind femur dorsally and ventrally with distinct dark brown color-pattern; fore and middle tibiae usually, hind tibia always with dark spots at bases of tibial spines and not infrequently with darkened base ( Figs. 6–11 ); venter uniformly pale ( Fig. 3 ). SURFACE AND VESTITURE: Dorsum smooth, moderately shining; with dense simple uniformly pale setae, rarely somewhat darkened on cuneus, first antennal segment with two pale medial spines, each femur with a few dark or pale spines apically, tibial spines dark brown to whitish. STRUCTURE: Head: Moderately produced anteriorly in dorsal view; eyes relatively large, occupying almost entire height of head in lateral view, posterolateral margins of eyes contiguous with anterolateral margins of pronotum; vertex weakly convex, frons moderately sloping anteriorly in lateral view, clypeus weakly produced, usually not visible in dorsal view; antennae inserted near ventral margin of eye; second antennal segment linear; labium reaching metacoxae. Thorax: Pronotum trapezoidal, 1.9–2.4 times as broad as long, disk weakly convex, calli indistinct, posterior margin nearly straight or weakly concave medially, lateral margins straight, posterolateral angles broadly rounded; mesonotum moderately exposed. Legs: femur elongate, not swollen, usually slightly broader medially, tibia cylindrical, third tarsal segment equal to length of first and second combined, claw elongate, strongly bent at middle, pulvillus small, reaching midpoint of claw, attached to the claw along entire length.

GENITALIA: Genital segment large, 0.6–0.7 of abdomen, distinctly longer than basal width, without distinctive ornamentation. Parameres: Right paramere lanceolate, with slender apical process; left paramere with obtuse sensory lobe and straight, gradually tapering apical process. Apex of theca: Shape typical of many phylines, comparatively long and narrow. Vesica: S-shaped, comparatively large, strongly coiled, body of vesica of distinctive curvature and form, with several closely approximating ridges running along margin of lateral strap, apically with two characteristically shaped blades, small blade more or less twisted along axis and attenuated laterally, large blade long and thin, gradually curved ( Figs. 12–17 ); secondary gonopore far removed from apex of vesica, with well developed sculpture and long and distinct gonopore sclerite, placed on membranous, dentate lobe.

Female. Macropterous. Similar to male in color, structure, and vestiture, but more strongly ovoid, eyes slightly smaller than in male, with correspondingly broader vertex. GENITALIA: Dorsal labiate plate of bursa copulatrix with almost triangular sclerotized rings, their anterior angles distinctly tapering ( Fig. 22 ); posterior wall simple; vestibulum narrow, S-shaped, irregularly sclerotized, vulva with two almost straight sclerites at sides ( Fig. 23 ).

Hosts. Hosts are documented for three out of six species of the genus, and available data may suggest that either Leucodellus spp. feed on a broad range of plant groups or some host data represent a sitting record.

Distribution. All species of Leucodellus inhabit mountain terrains with moderate elevations. The genus has a highly disjunct distribution, with two closely related species, L. amygdali and L. zagdani , known from the Caucasus, while the rest of the species occurring in Nepal, Sichuan province and Tibet Autonomous Region of China. The two ranges are separated by as much as 3500 km and the genus remains unknown from the relatively well sampled mountains of Central Asia.

Discussion. A number of features of the male and female genitalia listed in the revised diagnosis unequivocally indicate the monophyly of Leucodellus . Duwal et al. (2010) being unaware of the paper by Li & Liu (2007) described the monotypic genus Leucophyllus and correctly pointed out that the new genus is similar in overall appearance and vesica structure to Plagiognathus pallescens (already transferred to Leucodellus by Li & Liu 2007).

Careful investigation of Leucophylus variegatus and all species currently assigned to Leucodellus allows me to conclude that they are congeneric. The peculiar vesical structure, large male genital segment and triangular sclerotized rings of the dorsal labiate plate are similar in all species. Leucodellus and Leucophylus share a common color pattern, similar pretarsal structure and vestiture. Based on the above features, the genus Leucophylus Duwal, Yasunaga & Lee, 2010 is synonymized with Leucodellus Reuter, 1906 .

Figures

FIGURES 1 – 5. Habitus images, males. 1 — Leucodellus albidus; 2 – 3 — Leucodellus zagdani: 2 — dorsal view, 3 — lateral view; 4 — Compsidolon nathaliae; 5 — Leucodellus amygdali.

FIGURES 12 – 17. Vesicae of Leucodellus spp. 12 — L. albidus; 13 — L. amygdali; 14 — L. zagdani; 15 — L. pallescens; 16 — L. variegatus; 17 — L. xizangensis.

FIGURES 18 – 23. Genital structures. 18 – 20, vesicae: 18 — Compsidolon nathaliae, 19 — Compsidolon nebulosum; 20 — Compsidolon pumilum; 21 – 22, dorsal labiate plate: 21 — Compsidolon nathaliae, 22 — Leucodellus albidus; 23 — opening of vestibulum in Leucodellus albidus.

FIGURES 6 – 11. Color pattern on ventral side of hind femur in males of Leucodellus spp. 6 — L. albidus; 7 — L. amygdali; 8 — L. pallescens; 9 — L. variegatus; 10 — L. xizangensis; 11 — L. zagdani.