Sphyrometopa, Carl, 1908

Piotr Naskrecki, 2000, Katydids of Costa Rica / Vol. 1, Systematics and bioacoustics of the cone-head katydids (Orthoptera: Tettigoniidae: Conocephalinae sensu lato)., Philadelphia, PA: The Orthopterists Society at the Academy of Natural Sciences of Philadelphia, : 95-97

SPHYROMETOPA Carl, 1908

1908 Carl, Revue Suisse de Zool. 16: 135; type species: Sphyrometopa femorata Carl, 1908

Diagnosis

Body robust, size medium for the subfamily; both sexes mesopterous, with tegmina not reaching apex of abdomen ( Figs. 25 A, 37F); tegumen moderately rugose. Fastigium of vertex nearly 4 times broader than scapus, short and blunt, continuous with fastigium of frons; no traces of genal carinae present; frons weakly convex. Fore femora unarmed ventrally, mid and hind femora armed on lower anterior margins with minute spines. Male cercus unique ( Figs. 25 E-F); ovipositor shorter than half of femur, distinctly upcurved, acute apically.

Description (male except where specified)

Head.— Fastigium of vertex about 4 times as wide as scapus, blunt and as long as diameter of eye; fastigium of vertex continuous with fastigium of frons ( Fig. 25 B). Eyes small relative to size of head, weakly protruding. Frons weakly convex, smooth; tegumen of head weakly rugose, without traces of genal carinae; face broad. Mandibles and labrum weakly asymmetrical.

Thorax and wings.— Dorsal surface of pronotum moderately rugose, flat; anterior dorsal margin straight, posterior one straight to weakly convex ( Fig. 25 C); lateral lobes with posterior angle narrowly rounded; humeral sinus weakly developed. Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobe of pronotum. Prosternum armed with two thin, widely separated spines (modified basisternum); mesosternum with lateral lobes of basisterna triangular, oblique; metasternal lobes also triangular and oblique but with their bases wider than those of mesobasisterna.

Tegmina in both sexes shortened, not reaching end of abdomen; tegmina oval to narrowly triangular with rounded apex ( Figs. 25 A-B); hind wings reduced, as long as 1/3 to 3/4 of tegmina. Stridulatory apparatus of male well developed; stridulatory area of left wing thickened, with dense network of secondary veinlets; stridulatory

file (vein AA 1) weakly curved ( Figs. 48 A-C), with narrow, regularly spaced teeth.

Legs.— Fore coxa with an elongate, forward projecting spine dorsally. All femora unarmed dorsally; fore femora unarmed ventrally, mid and hind femora armed ventrally on anterior ventral margins with few minute spines; only posterior genicular lobes of mid and hind femora armed with short spines, remaining lobes obtuse. Fore and mid tibiae unarmed dorsally, both ventral margins with immovable, short spines; hind tibia armed on both dorsal margins but with only 2 small spines on anterior ventral margin; apex of tibia with two pairs of ventral and one pair of dorsal movable spurs. Tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area only weakly swollen, with pair of small, elongated pits below tympanal slits.

Abdomen.— Dorsal surface of abdominal terga smooth, unmodified. Male 10th tergite with deep apical emargination, supraanal plate small, triangular; female 10th tergite with deep, narrowly triangular incision. Male cercus unique ( Figs. 25 E-F), its base stout, with two dorsal lobes and long apical projection, curved backwards, overhanging basal part of cercus, its tip serrated ventrally; female cercus, simple, conical, but with apex distinctly attenuated. Subgenital plate of male with pair of styli, its posterior margin straight or with small, triangular emargination; female subgenital plate widely trapezoidal, its apex straight or weakly emarginated.

Male concealed genitalia with inner phallic lobes strongly sclerotized, forming a pair of divergent titillators (titillators not separated from membrane); outer phallic lobes with small, sclerotized patches ( Fig. 26 C). Ovipositor short, sickle-shaped ( Fig. 25 A), very thick at base (when seen from below).

Coloration.— General coloration mottled grayish-brown to dark brown ( Fig. 37 F); face with large, black patch, bordered with thin, diffused, whitish margins ( Fig. 25 B); legs mottled brown, lower half of outer pagina of hind femur black, bordered by diffused, whitish stripe; dorsal portion of abdomen usually lighter; cerci yellowishbrown with dark apical portions.

Remarks.— The genus Sphyrometopa includes two species, both of them originally described from Costa Rica, and both apparently endemic to this country [although an unidentified species of Sphyrometopa was reported from Panama by Nickle (1992)]. The closest relatives of the genus seem to be genera Dectinomima Caudell , Eppia Stål , and Uchuca Caudell. The unique appearance of the members of the genus, with shortened wings, characteristic coloration, and the shape of male cerci, makes them some of the easiest to identify species of Costa Rican Tettigoniidae . They are also the only species of the family that can be found almost exclusively on the forest floor, among fallen leaves or on low, herbaceous vegetation. Rentz (1976), who reviewed the genus, noted that they inhabit primary growth forests and only secondarily move to clearings and forest openings of early secondary growth.At La Selva Biological Station, S. atlantica can be found along primary forest trails among low vegetation, especially if the habitat is vegetated by Selaginella eurynota A. Braun, Diffenbachia seguine (L.) Schott, and Costus malortieanus H.A. Wendl. I also observed this species deep within the primary forest, in places with sparse vegetation at the ground level and the canopy permitting at least a small amount of light to reach the ground.

Unlike adult individuals, nymphs of Sphyrometopa atlantica are light green, with small, dark, irregular patches ( Fig. 36 F). They undergo at least 5 nymphal instars before reaching maturity. The 5th nymphal instar loses its green coloration and turns dark brown. Nymphs of S. femorata turn brown much earlier or are never green. Nymphs of both species are diurnal. They occur in green vegetation and rarely descend to the ground. Adults are strictly nocturnal and spend most of their time on the ground, with the exception of singing males that have been observed singing from underneath large leaves at least 1 m above the ground. Little is known about the diet of Sphyrometopa spp. Rentz (1976) reported that adults of S. atlantica had been seen feeding on flowers of ginger ( C. malortieanus ). In captivity individuals of this species thrived for several months on the diet of corn, carrots, lettuce, and apple.

Figures

FIG. 24. Eppia truncatipennis. A. female - habitus, B. female face, C. female head and pronotum, dorsal view, D. titillators, everted, E. male cerci, dorsal view.

FIG. 25. Costa Rican species of Sphyrometopa. A-E. S. femorata: A. female - habitus, B. female face, C. female head and pronotum, dorsal view, D. male cerci, dorsal view, E. male left cercus, lateral view, F. S. atlantica - male left cercus, lateral view.

FIG. 26. Costa Rican species of Sphyrometopa and Moncheca. A. S. femorata - male left tegmen, B. S. atlantica- male left tegmen, C. S. femorata - titillators, everted, D-F. M. pretiosa: D. female head and pronotum, lateral view, E. female head and pronotum, dorsal view, F. male cerci, dorsal view, G. male cerci, lateral view.

FIG. 36. Costa Rican species of Conocephalinae s. l. A. Conocephalus angustifrons - male, B. Caulopsis cuspidata - female, C. Acantheremus colwelli - male, D. Vestria punctata - male and female, in copula, E. Copiphora hastata - male, F. Podacanthophorus vargasi - female, G. Copiphora rhinoceros - male eating a snail, H. Subria sylvestris - male, brown form.

FIG. 37. Costa Rican species of Conocephalinae s. l. A. Erioloides longipennis - female ovipositing, B. Erioloides longinoi - male, C. Eriolus penicillus - female, D. Conocephalus cinereus - male, macropterous form, E. Neoconocephalus triops - male, brown form, F. Sphyrometopa atlantica - male, inset - nymph.

FIG. 46. Stridulatory files of Costa Rican species of Conocephalinae s. l. A. Bucrates capitatus, B. ditto, enlarged fragment, C. Bucrates clausus, enlarged fragment, D. ditto, entire file, E. Pyrgocorypha rogersi, entire file, F. ditto, enlarged fragment, G. Pyrgocorypha hamata, enlarged fragment, H. ditto, entire file.

FIG. 48. Stridulatory files of Costa Rican species of Conocephalinae s. l. A. Sphyrometopa femorata, C. Sphyrometopa atlantica, C. ditto, enlarged fragment, D. Eppia truncatipennis, enlarged fragment, E. ditto, entire file, F. Caulopsis cuspidata, entire file, G. ditto, enlarged fragment, H. Caulopsis microprora, enlarged fragment, I. ditto, entire file.