Gonatacanthus gahavisuka, Naskrecki, Piotr & Rentz, David C. F., 2010

Naskrecki, Piotr & Rentz, David C. F., 2010, Studies in the orthopteran fauna of Melanesia: New katydids of the tribe Agraeciini from Papua New Guinea (Orthoptera: Tettigoniidae: Conocephalinae), Zootaxa 2664, pp. 1-35 : 15-17

Gonatacanthus gahavisuka n. sp.

( Figs. 6 A–J)

Type locality. PAPUA NEW GUINEA: Eastern Highlands Prov., Mt. Gahavisuka Provincial Park, nr. IBR shelter huts (6°0'51.8''S, 145°24'46.9''E), 2311 m, 30.iv.– 1.v.2009, coll. P. Naskrecki—male holotype ( ANSP) Differential diagnosis. This species cannot be confused with other species of this rather poorly defined genus thanks to the unique cercus morphology of the male, which bears two series of small, sharp spines on its long, apical arm ( Fig. 6 C). Two other species of Gonatacanthus are known from New Guinea: from G. decipiens Karny it differs in the nearly complete reduction of the female tegmina (tegmina reaching the end of the second tergite in G. decipiens ; male of this species is unknown), and from G. griffini Karny it differs in the shape of the male cercus, which is bent and bidentate apically.

General. Body cylindrical, small, robust; male brachypterous, female squamipterous ( Fig. 6 A).

Head. Frons weakly concave, oblique, smooth ( Fig. 6 B); lateral carinae absent. Fastigium of frons well developed, separated from fastigium of vertex by small gap; fastigium of vertex triangular, as wide as 1/2 of antennal scapus, shorter than half of scapus; eyes globular, moderately protruding; median ocellus present, circular; lateral ocelli absent; antennae more than twice as long as body.

Thorax. Pronotum surface smooth; anterior margin of pronotum straight ( Fig. 6 I), flat; metazona weakly convex ( Fig. 6 J), posterior edge of metazona broadly rounded, lateral lobe almost 3 times as long as high; marginal fold of pronotum narrow, smooth. Thoracic auditory spiracle minute, circular, completely hidden under pronotum. Sternum flat; prosternum armed with two short spines; mesosternum posterior lobes with small protuberances; metasternum unarmed.

Legs. Front femur armed on both margins, spines on posterior margin minute; genicular lobes of front femur blunt, unarmed; front tibia with both ventral margins armed with 7–9 spines, ventral spines on front tibia as long as tibia diameter. Mid femur armed with 5 spines on anterior ventral margin only; genicular lobes of mid femur unarmed Hind femur armed on anterior margin only; genicular lobes of hind femur armed with single spine on both sides.

Wings. Tegmen nearly completely hidden under metazona of pronotum, barely reaching posterior margin of 1st abdominal tergite; tegminal venation strongly reduced; anterior margin rounded; apex of tegmen somewhat truncate ( Fig. 6 G). Mirror roughly rectangular; stridulatory file flat, 1.15 mm long, 0.06 mm wide, with 109 teeth; hind wing absent. Female tegmina squamiform, shorter than half of pronotum, separated by distinct gap.

Abdomen. Tenth tergite unmodified. Cercus with two inner lobes, apical lobe elongate and with series of minute spines on both dorsal and ventral edges ( Fig. 6 C); paraprocts unmodified; epiproct small and rounded. Phallus with weakly developed, paired, slender titillators ( Fig. 6 E). Subgenital plate broadly trapezoidal, with small, triangular apical incision ( Fig. 6 D); styli cylindrical, about twice as long as wide. Female subgenital plate weakly sclerotized in its central portion, lateral edges of plate with two pairs of small sclerites; posterior margin with shallow, triangular incision ( Fig. 6 F).

Ovipositor. Ovipositor about as long as hind femur (ratio femur/ovipositor 0.79–1.02), slightly curved; dorsal edge of upper valvula parallel to lower valvula; apex with both valvulae smooth, apex pointed ( Fig. 6 H).

Coloration. Coloration light brown ( Fig. 6 A); face with broad, dark vertical stripe; clypeus and labrum yellow, without markings ( Fig. 6 B). Pronotum with diffuse, dark stripe, continuous with that on abdomen. Legs light brown, irregular, small dark patches only on front tibia; abdominal terga with dark, central stripe.

Measurements (4 males, 4 females). body w/wings: male 19–23 (20.9±1.7), female 28.5–32 (29.9±1.5); pronotum: male 7.5–8 (7.8±.2), female 6.3–7 (6.8±.4); tegmen: male 3.7–4.5 (4.1±.3), female 1.8–2.3 (2±.2); hind femur: male 12–13 (12.3±.5), female 12.5–14 (13.5±.7); ovipositor: 11–13.5 (11.6±1.3) mm.

Material examined (10 specimens). Papua New Guinea: Eastern Highlands Prov., Mt. Gahavisuka Provincial Park, nr. IBR shelter huts, elev. 2311 m (6°0'51.8''S, 145°24'46.9''E), 30.iv.–1.v.2009, coll. P. Naskrecki— 4 females, 4 males (holotype, paratypes), 1 nymph female, 1 nymph male ( ANSP, MCZ).

Etymology. Named after Mt. Gahavisuka , the type locality of the new species.

Figures

FIGURE 6. Gonatacanthus gahavisuka n. sp.: A. paratype female; B. face; C. male cercus, dorsal and ventral view; D. male subgenital plate; E. titillators; F. female subgenital plate; G. male left tegmen; H. ovipositor; I. male head and pronotum, dorsal view; J. ditto, lateral view.