Podacanthophorus alas, Piotr Naskrecki, 2000

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, : 124-127

PODACANTHOPHORUS Naskrecki , gen. n.

Type species: Podacanthophorus alas sp. n., here desig- nated

Diagnosis

Body small as for the subfamily, relatively robust; both sexes macropterous ( Figs. 34 A, 36F). Head with fastigium of vertex 2-3 times as long as diameter of eye, conical, with distinct ventral keel. Head narrow, frons flat or weakly convex; genae without lateral carinae. Pronotum wide, with lateral lobes oblique; metazona in males entirely covers stridulatory apparatus. Thoracic sterna unarmed. Male cerci with long basal spine; titillators needlelike; ovipositor strongly curved upwards, pointed apically.

Description (male except where specified)

Head.— Fastigium of vertex conical, 2-3 times as long as diameter of eye ( Figs. 35 A-I), with well developed, lamelliform, ventral keel; dorsal surface of fastigium smooth or with longitudinal furrow; ocelli reduced, hardly discernible; fastigium of vertex continuous with fastigium of frons. Antennal sockets separated by distance equal to width of scapus. Eyes globose, moderately protruding, small relative to size of head; frons flat or weakly convex; genae without lateral carinae. Labrum and mandibles symmetrical.

Thorax and wings.— Pronotum widely semi-circular in cross-section, with lateral lobes oblique; dorsal surface of pronotum smooth, flat; anterior margin of pronotum concave, posterior margin convex ( Figs. 35 B-F); lateral lobes not well differentiated from dorsum of pronotum, lacking humeral sinuses ( Figs. 35 G-I); shape of pronotum sexually dimorphic: metazona in male much longer, narrowed towards apex, entirely covering stridulatory apparatus. Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobes of pronotum. Thoracic sterna unarmed, without well developed basisternal lobes.

Wings in both sexes fully developed or somewhat reduced; tegmina reaching or surpassing apices of hind femora ( Fig. 34 A, 36F); hind wings reaching apices of tegmina or somewhat shortened. Stridulatory apparatus of male well developed; stridulatory file straight or weakly curved ( Figs. 51 B-D), teeth thin and very wide; stridulatory area of left wing without secondary venation, nearly square; mirror of right wing nearly square, with very well developed veinlet next to AA 1. Posterior margin of front wing straight or weakly convex; apex of front wing narrowly rounded.

Legs.— Legs robust, their tegumen strongly rugose. Fore coxa with an elongate, forward projecting spine dorsally; middle and hind coxa without spine; all trochanters unarmed. All femora unarmed dorsally but armed with long to very long spines on both ventral margins; all femora robust, strongly flattened laterally ( Figs. 35 K-N); anterior ventral spines on hind tibia often very long, flattened; genicular lobes of hind femora armed with long spines, lobes on fore and mid femora unarmed in most species. Front and mid tibia unarmed dorsally, their ventral margins with immovable spines about as long as tibia diameter; tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area weakly swollen, cuticular flaps above tympanum nearly transparent; hind tibia armed on all four dorsal and ventral margins; apex of tibia with two pairs of ventral and one pair of dorsal movable spurs.

Abdomen.— Dorsal surface of abdominal terga smooth, unmodified. Male 10th tergite with deep, narrow incision, resulting in two wide lobes; tergal lobes of female 10th tergite similar to that of conspecific males but narrower and pointed apically; supraanal plate in both sexes small, broadly rounded apically; male cercus narrowly cylindrical, with long, basal internal spine; cercal spine completely hidden under 10th tergite, invisible from above ( Figs. 34 B, 34D, 34F); female cercus, simple, narrowly conical. Subgenital plate of male triangular, with small, narrow apical incision; styli well developed; female subgenital plate approximately triangular, with or without shallow apical emargination. Titillators of male well developed, shaped like a pair of cuticular needles, straight or sinusoidal ( Figs. 34 C, 34E, 34G). Ovipositor sickle-shaped, strongly upcurved, its margins parallel or ovipositor somewhat dilated midlength; both dorsal and ventral margins of ovipositor smooth, its apex pointed; ovipositor always shorter than hind femur ( Fig. 34 A, 35J).

Coloration.— General coloration light green ( Fig. 36 F); face light green to creamy white, sometimes labrum and mandibles dark purple; fastigium of vertex yellow or reddish; pronotum of male with species-specific color markings in metazona; tegmina with contrastingly yellow venation; legs with densely distributed small black and larger emerald dots; ventral spines of femora white with black tips.

Remarks.— This new genus is closely related to the genus Eriolus but can be easily separated by the unique shape of the pronotum; the presence of long, flattened spines on hind femora ; stout, robust legs; the structure of male cerci; and general, somewhat dorso-ventrally flattened appearance of live individuals. The two genera share similar features of the fastigium of vertex, the stridulatory apparatus, thoracic sterna, and the ovipositor.

All species of the genus are exclusively arboreal and nocturnal, and being unable to fly actively, are never attracted to light. This makes collecting them difficult, and specimens of the genus are rare in entomological collec- tions. Most of the specimens of the four new species described below were collected by either collecting directly in the canopy level of the forest or by canopy fogging.

Little is known about the biology of Podacanthophorus spp. In captivity, P. alas and P. vargasi thrived for several months on the diet consisting of various fruits and vegetables, as well as dead insects. The call is known for only P. alas (see description below). Females lay eggs in stems of plants. Eggs are long and thin, somewhat resembling thin grains of rice.

Etymology.— The generic epithet relates to the large femoral spines typical of all species of the genus.

Figures

FIG. 34 Costa Rican species of Podacanthophorus. A-C. P. alas: A. female, habitus, B. male cerci, ventral view, C. titillators, D-E. P. vargasi:, D. male cerci, ventral view, E. titillators, F-G. P. maylinae: F. male cerci, ventral view, G. titillators.

FIG. 35. Costa Rican species of Podacanthophorus. A. P. alas - male face, B-F. head and pronotum, dorsal views: B. P. alas - female, C. P. alas - male, D. P. vargasi - male, E. P. maylinae - male, F. P. nelciae - female; G-I. head and pronotum, lateral views: G. P. vargasi - male, H. P. maylinae - male, I. P. nelciae - female; J. P. nelciae - ovipositor; K-N. left hind femora, outer views: K. P. alas, L. P. vargasi, M. P. maylinae, N. P. nelciae.

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. 51. Stridulatory files of Costa Rican species of Conocephalinae s. l. A. Subria sylvestris, C. Podacanthophorus maylinae, C. Podacanthophorus alas, D. Podacanthophorus vargasi, E. Pluviasilva levis, F. Pluviasilva mexicana.