Neodelphax sakakibarai Remes Lenicov & Brentassi, 2017

Marino De Remes Lenicov, Ana M. & Brentassi, M. Eugenia, 2017, New taxa and combinations in Neotropical Delphacini (Hemiptera: Fulgoroidea), Zootaxa 4281 (1), pp. 280-290 : 283-284

Neodelphax sakakibarai Remes Lenicov & Brentassi , sp. n.

( Figs 1–13 )

Type locality: Villa Carmela , Departamento Tafí, Tucumán, Argentina, 26°46'55"S, 65°15'33"W.

Description. Male medium-sized, with macropterous and brachypterous forms ( Figs 1, 2 ). Length of macropterous form: 3.9 mm in male, 4.2 mm in female; brachypterous form: 2.7 mm in male, 3 mm in female.

Darkish, ferruginous. Face with carinae testaceous pale, areas between carinae dark brown, irregularly pale dotted, except for clypeus which is uniformly colored; rostrum yellowish with darkish tip; ocelli and antennae yellowish with distinctive blackish antennal flagellum; vertex and pronotum with carinae testaceous pale; mesonotum uniformly brown except for small, testaceous apical mark; legs yellowish except coxae; upper side of abdomen uniformly dark; pygofer dark brown with small pale-colored area on each dorsolateral margin; anal style pale in dorsal view; anal spines dark brown; forewings (brachypterous) coriaceous, ferruginous, with apical half of suture black and adjacent area of wing darkish, in macropterous specimens, translucent brown forewings, with dark veins, except for longitudinal sub–hyaline subcostal+radial apical area; with elongate dark marking at tip of clavus and wide ferruginous semicircular-shaped area from cross-veins to apical margin up to M1 vein. Females: similar to males but generally lighter; areas between frontal carinae light brown, narrowly bordered with black.

Structure. Macropterous male.

Head ( Figs 1, 3 ) including compound eyes 2.7x wider than vertex at base, and slightly narrower than pronotum (0.9:1); vertex subquadrate, lateral margins subparallel, in midline approximately as long as wide at base; basal compartment at hind margin 3x as wide as greatest length, about 0.5x length of vertex; stem of Y-shaped carina slender, delimiting triangular shallow depressed areas on both sides; other carinae of head prominent. Vertex evenly rounded to frons in profile, fastigium slightly projecting beyond eyes; arms of submedian carina meeting at acuminate angle far below lower level of eyes. Frons ( Fig. 4 ) longer than wide (2:1) in middle line, widest part at level of ventral margin of eyes, lateral margins slightly convex; submedian carinae prominent, straight, separate for>3/4 total length, branches closer to each other than to laterals, shallowly concave laterally; frontal area nearly straight in profile. Genal carina arising from lateral edge of frontoclypeal suture and ending before base of antenna. Postclypeal disc longer than width at base (1.4:1); median and lateral carinae prominent, submedian carinae continuing onto anteclypeus. Post and anteclypeus together little shorter than frons (0.9:1). Rostrum reaching middle of metacoxa, subapical segment slightly longer than apical segment (1:0.8). Antennal segments cylindrical, slender, surpassing base of postclypeus; basal segment as long as width, second segment longer than first segment (2:1); number and arrangement of sensory fields of pedicel: 14 in 5 rows.

Pronotum ( Fig. 3 ) wider than head (1.1:1), in midline slightly shorter than vertex; lateral carinae distinct, curved laterally behind eye, not reaching hind margin. Mesonotum 3x length of pronotum medially in macropterous and 2x in brachypterous form; carinae distinct, straight, lateral carinae ending on margin, median carina becoming obsolete prior to scutellum, which is as smooth as scutum. Forewings ( Fig. 1 ) rounded at apex, length 3x its width at apical region, in brachypterous form reaching genital segment and hind wing reduced to scale. Post-tibial spur ( Fig. 5 ) oval, concave on inner surface, slightly shorter than basitarsus (0.7:1) with about 22– 23 slender black-tipped teeth on posterior margin plus inconspicuous apical tooth. Postbasitarsus slightly longer than tarsomere II and III together (1:0.8); spinal formula: 5 (grouped 2 + 3) – 7 (grouped 2 + 5) – 4. Drumming organ ( Fig. 6 ) distinctive, with second abdominal tergite differentiated into distinctive plate readily visible externally surrounded by white membranous area; central plate subquadrate, medially convex, laterocaudally closed by sclerotized furrows.

Genitalia. Genital segment ( Figs 7–9 ) ovate in caudal view, slightly wider than height; dorsal margin, deeply excavated to hold anal segment; trapezoidal in lateral view, ventral length 3x dorsal length; dorsocaudal margins smoothly rounded, ventrolaterally slightly projected, distinctively scabrous and sclerotized; ventrocaudal margin deeply excavate with small median process. Diaphragm bridge subrectangular, armature much broader than height, strongly sclerotized; middle of dorsal margin convex, slightly lipped in lateral view. Parameres rather long, slender, distally diverging and tapering, angled dorsal in apical third, apex recurved outwards; basal angle with well developed rounded edge directed medioventrad, inner lateral margin smooth. Phallotheca tubular, terete to subterete, laterally slightly compressed, obliquely dorsally directed and armed with relatively short spinous lateral flag-like process 1/3 distance from apex, with crown of 6–8 small teeth surrounding dorsal and lateral sides of apical phallotrema; phallotrema circular exposed on left side; suspensorium short, plate-like, widely attached to ventral base of phallotheca. Connective nearly straight, compressed. Anal segment broad, ventrally membranous, widely separated at base in caudal view, with laterocaudad margins projected in strong claw-like process medioventrad directed. Anal style relatively small, little higher than wide.

Measurements of macropterous: L.: 3.95 (3.91–4.08); B.L: 2.95 (2.66–3.08); W.:1.08 (1.06–1.16); w.: 0.78 (0.75–0.8); w.l.: 3.07 (3.05–3.15); t.n.: 22–24.

Measurements of brachypterous: L.: 2.70 (2.50–2.83); W.: 0.97 (0.91–1); w.: 0.75; w.l.: 1.61 (1.55–1.65); t.n.: 22–23.

Female. Macropterous form: Structure and color pattern similar to male but lighter; abdominal segments usually with darkish marks on each side of tergites and sternites. Drumming organ inconspicuous, without major morphological variations. Brachypterous form: structurally similar to brachypterous males, color pattern varying from darkish to uniformly castaneous, with intercarinal frontal region, gena and forewings, brownish.

Genitalia ( Figs 10–13 ): Abdomen with wide central membranous part between pregenital sclerites. Genital scale ( Fig. 11 ) approximately rectangular, regularly sclerotized, with two strong submedian spinose processes as long as half scale length. Valvifers VIII ( Fig. 12 ) elongate, strongly broadening towards base, with distinctive basal lobe on inner margin. Gonapophyses IX ( Fig. 13 ) slender, dorsally finely denticulated, slightly curved in basal 1/2, with ca. 38–40 small sharp teeth on distal ½ of dorsal margin, with distal apex narrow and strongly angled; anal style moderately short.

Measurements of macropterous: L.: 4.06 (3.83–4.33); B.L.: 3.11 (2.66–3.50); W.:1.13 (1.08–1.16); w.: 0.8 (0.75–0.85); w.l.: 3.03 (2.95–3.25); t.n.: 22–24.

Measurements of brachypterous: L.: 3.28 (3.16–3.5); W.: 1; w.: 0.8; w.l.: 1.6; t.n.: 22–23.

Etymology. This species is named in honor of Dr. Albino M. Sakakibara, from the Universidad Federal do Paraná, Brazil, in recognition of his intense and prolific work as a taxonomist of auchenorrhynchous Hemiptera .

Remarks. Neodelphax sakakibarai can be easily recognized from the apparently closely related and widely distributed species N. fuscoterminata by the following characters: coloration pattern of body quite uniformly darker, forewings in macropterous form with fuscous marks and hyaline areas more extended and intensely colored; submedian frontal carina joined near apical margin, with the branches parallel and closely approximated; male genitalia with diaphragm bridge subrectangular with armature strongly sclerotized, parameres more slender and phallotheca with spinous lateral flag-like process at 1/3 distance from apex. The four-sided shape and spinous processes of the genital scale and the expanded base of valvifers VIII are distinctive in the females.

Distribution. Argentina (Salta, Tucumán, Catamarca and Buenos Aires).

Biology: Neodelphax sakakibarai is common and abundant on meadows and cultivated fields in valleys of the Northwest of Argentina. The majority of the collection locations are in sub-Andean areas that belong to the Monte biogeographic province, that is characterized by a warm, shrubby desert extending to the east of the Andes mountains between the Puna and Patagonia, from Salta (24°35`S) to Chubut (43°26`S) provinces ( Morello 1958). Field studies have shown that its populations abruptly increase during late winter and early spring living on several wild grasses surrounding cultivated maize areas affected by the Mal de Río Cuarto virus (MRCV) (Remes Lenicov unpubl. data). Further studies will determine its role in the epidemiology of this disease.

Several species of plants have been registered predominantly in corn agroecosystem of subtropical areas in the north of Argentina where N. sakakibarai was captured: Sorghum halepense L., Cynodon dactylum (L.) and Setaria sp. ( Poaceae ) and the dicots Eryngium sp. L ( Apiaceae ), Solanum nigrum L. ( Solanaceae ) and Sida rhombifolia L. ( Malvaceae ) (E. Virla, Pers. com., April 2017).

Natural Enemies. Nymphs and adults were found parasitized by unidentified species of Elenchidae (Strepsiptera) and Dryinidae (Hymenoptera) .

Material Examined. Holotype male (macropter): ARGENTINA, Tucumán, Villa Carmela , on grass, 28.VIII.1998, Virla col. Paratypes: 3 males (brachypters), 3 females (macropters), 2 females (brachypters), same data as holotype ; 1 male and 1 female (macropters), Tucumán, Las Tipas, Trancas , 28.I.1999, Virla col. ; 1 male (macropter), Salta, Rosario de Lerma , 17.V.1994 ; 1 male (macropter), Catamarca, El Rodeo , 27.II.1999, Virla, col. ; 1 male (macropter), 1 female (brachypter), Buenos Aires, Balcarce , on maize, XII.1991, Remes Lenicov col. ( MLP) ; 1 male (macropter), 1 female (brachypter), Buenos Aires, La Plata , on grass, 10.V.1999, Barrios col.

Other Material Examined. ARGENTINA: Tucumán, 5 males (macropters), 3 males (brachypters), 3 females (macropters), 2 females (brachypters), Villa Carmela, on Cynodon sp.

Figures

FIGURES 1 – 13. Neodelphax sakakibarai sp. n. 1, male holotype, habitus, lateral view; 2, brachypter male, habitus, dorsal view; 3, head and thorax, dorsal view; 4, head, frontal view; 5, apex of hind leg (post tibial spur and tarsi); 6, pregenital segments of abdomen, dorsal view; 7, male genitalia, caudal view; 8, pygofer, ventro caudal view; 9, genital complex, left lateral view. Female: 10, genitalia, ventral view; 11, genital scale, ventral view; 12, right valvifer VIII; 13, median gonapophysis IX, lateral view. Scale lines: Figs 1 – 4 = 1 mm; Figs 5 – 13 = 0.5 mm.