Problematode Gaiani, 2017

Gaiani, Marco A., 2017, Problematode: an enigmatic new genus of Membracidae (Hemiptera) with two new species from Venezuela, Zootaxa 4281 (1) : -

Problematode Gaiani gen. nov.

Type species. Problematode sakakibarai Gaiani sp. nov.

Diagnosis. Mid-sized treehoppers (8.3– 10 mm). Body depressed, hirsute ( Figs. 1–4 ). Forewings thickened in basal half (veins obscured), surface with recumbent white pilosity; apical half with venation reticulated, veins with recumbent white pilosity, cells not pilose. Pronotum with median longitudinal carina; with or without processes, when present, as an elevated posterior keel not covering scutellum; with two dark bare, short, glabrous projections at each side of medial carina and keel ( Figs. 2, 4, 6, 7 ). Pro- and metatrochanters with a definite suture separating them from their respective coxae, mesotrochanters fused with femora. Pro- and mesofemora with a large, blunt spine on ventral border ( Figs. 15–17 ). Meso- and metacoxal cavities widely separated, thoracic sternites widely exposed ( Fig. 8 ). Aedeagus stout, “U”-shaped, gonopore apical; second valvulae abruptly widened in apical third.

Description. Head ( Figs. 2, 4–5, 9–10 ) as wide or wider than pronotum in dorsal view, eyes stalked; distinct triangular dorsal projections at each side of coronal suture, closer to each other than to eyes, with small glabrous depression or concavity admedially at their base in frontal view. In anterior view: ocelli elevated, closer to each other than to eyes; head covered in long white adpressed hairs ( Fig. 5 ). Vertex concave medially from occipital border to frontoclypeal suture; ventrolateral margins carinate. Frontoclypeus flat, transversely sunken at middle on apical 1/3rd; transverse carina or fold absent; covered with white semi-erect setae ( Fig. 8 ). Rostrum reaching base of metathoracic coxae; first segment short, barely longer than labrum; second segment longer, almost twice as long as third segment. Thorax. Distance from posterior margin of eye to wing base, in lateral view, 1.0 to 1.5x eye width. Pronotum ( Figs. 2, 4, 9–10 ). Punctation dense laterally, sparser at disc, space between punctations approximately 1.5x of punctation diameter; pubescence long, white, and adpressed; irregular depressed bare areas behind frontal margin with fine reticulated microsculpture ( Figs. 9–10 ), median longitudinal carina complete, sometimes developing into dorsoposterior keel ( Figs. 1, 6–7 ); short and glabrous dark projection at each side of medial carina and keel ( Figs. 2, 4, 6 ); dorsal postocular keel well developed; suprahumeral horns absent; posterior margin evenly rounded, posterolateral projections absent. Scutellum ( Figs. 2, 4 ). Base of scutellum weakly swollen, punctation sparse; apex as long or slightly longer than basal width; covered in long white decumbent setae, more abundant from base to midlength. Forewing ( Figs. 11, 13 ). Thickened in basal half, veins obscure; covered in decumbent white pilosity; R, M and Cu fused at base of forewing, R diverging first, M and Cu confluent for a short distance thereafter, apical half with reticulate venation (note: the identification of a second m-cu crossvein is difficult to assess due to the reticulation); apex of clavus acuminate; first and second anal veins confluent for short distance distally, directed towards claval suture and then abruptly curved to reach anal margin. Hind wing ( Figs. 12, 14 ). One r-m and one m-cu cross vein; membrane with arcuate chaetoids. Metepimeron. Concealed by forewing at rest. Legs ( Figs. 8 , 15–17 ). Meso- and metacoxa widely separated, thoracic sternites widely exposed; furcasternum reduced, without lobes. Pro- and meso-femora armed with a medial spine on ventral margin; pro- and meso-tibia amply triquetrous in cross section, with long setae, without rows of cucullate setae. Meso-trochanter immovably fused to femur, pro- and meta-trochanters with definite sutures separating them from their corresponding femora ( Figs. 15–17 ). Meta-femur without distal dorsal pair of cucullate setae, meta-tibia with three rows of cucullate setae, row I incomplete with basal 1/3 imperceptible, rows II and III complete ( Fig. 18 ).

Male. Abdominal sternites I–VII of similar length, VIII 1.3 x longer than VII; sternite VII length less than or equal to width; sternite VIII width more than 2x length. Lateral plate more than half the length of subgenital plate; sternite IX emarginate anteromedially; subgenital plate lobes incompletely fused, uniformly sclerotized without distinct fenestrae. Aedeagus short and stout; “U” shaped ( Figs. 18–19, 22–23 ); posterior arm straight; shaft tubular, in lateral view wider at mid length then tapering apically, with small scale-like spines on apical portion; gonopore large, apical. Styles elongated, apex bent at 90°, sclerotized, with a few sub-apical setae. Connective strap-like, semicircular ( Figs. 20, 24 ).

Female. VII sternite ( Fig. 26 ) as long or shorter than VI, widely concave caudad, exposing the base of the ovipositor; first valvulae straight and tapering to an acute apex ( Fig. 27 ); second valvulae abruptly expanded in apical third and then evenly tapered towards apex, dorsal margin with a row of close-set fine teeth ( Figs. 28–29 ).

Distribution. VENEZUELA: Aragua, Yaracuy. All specimens where collected within the Coastal Venezuela Montane Forest terrestrial ecoregion ( Olson et al. 2001).

Type species. Problematode sakakibarai sp. nov.

Etymology: From the Greek problema, “ problem” and tode, a demonstrative pronoun meaning “this”, “the following”. Gender neuter.

Discussion. The placement of Problematode gen. nov. into the current Membracidae classification is challenging. Species of Problematode gen. nov. will run to Euwalkeria in the generic key of Nicomiinae of Albertson & Dietrich (2005). They superficially resemble representatives of Euwalkeria in the reticulation of the forewings, but are easily distinguished by the male genitalia. For instance, Problematode gen. nov. has a stout “U” shaped aedeagus while Euwalkeria has a long falcate aedeagus with apical processes. The fused mesothoracic trochanters and the widely spaced meso- and metathoracic coxal cavities, amply exposing thoracic sternites, differentiate species of Problematode gen. nov. from all other known Membracidae . Only four specimens in this remarkable new genus have been studied, but all of them were collected in the Coastal Montane Forests of Venezuela ( Olson et al. 2001), a very rich ecosystem that is critically threatened by urban development and periodical forest fires. Further collecting efforts in this area using non-traditional methods (e.g., fogging, canopy traps, etc.) might yield additional specimens. Nymphal characters would help to clarify the taxonomic position of this genus.

Figures

FIGURES 1 – 10. Problematode sakakibarai sp. nov. (male holotype, MIZA): 1, lateral view; 2, dorsal view; 5, head, frontal view; 6, head and thorax lateral view (male); 7, head and thorax lateral view (female paratype); 8, head and thorax ventral view (male); 9, head and prothorax dorsal view (male, dorsal keel omitted). Problematode inerme sp. nov. (male holotype, MIZA): 3, lateral view; 4, dorsal view; 10, head and thorax (female paratype).

FIGURES 11 – 25. Problematode sakakibarai sp. nov. (male holotype, MIZA): 11, forewing; 12, hind wing; 18, aedeagus lateral view; 19, aedeagus caudal view; 20, styles dorsal view; 21, pygofer lateral view. Problematode inerme sp. nov. (male holotype, MIZA): 13, forewing; 14, hind wing; 15, 16, 17 pro-, meso-, and meta-thoracic legs respectively; 22, aedeagus lateral view; 23, aedeagus caudal view; 24, styles dorsal view; 25, pygofer lateral view.

FIGURES 26 – 29. Problematode inerme sp. nov. (female paratype, MIZA): 26, female abdomen ventral view; 27, first valvulae; 28, second valvulae; 29, apex of second valvulae.