Pluviasilva levis, 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, : 107-110

PLUVIASILVA Naskrecki , gen. n.

Type species: Pluviasilva levis sp. n., here designated

Diagnosis

Body slender; both sexes macropterous ( Figs. 29 A- B); tegumen smooth, glossy. Fastigium of vertex almost lamelliform, narrower than scapus; tegumen of head smooth, no traces of genal carinae present; frons flat or weakly convex; eyes small. All legs slender, armed on lower margins with minute spines. Male cercus unarmed, flattened laterally and dorso-ventrally expanded apically; ovipositor straight, slightly expanded midlength, apex blunt.

Description (male except where specified)

Head.— Fastigium of vertex almost lamelliform, at its base as broad as 2/3 of scapus; fastigium with distinct longitudinal furrow dorsally ( Figs. 29 I-J). Eyes small relative to size of head, not particularly protruding. Frons flat or weakly convex, smooth; tegmen of head smooth, without traces of genal carinae; face slender.

Thorax and wings.— Dorsal surface of pronotum smooth and glossy, flat; both anterior and posterior dorsal margins straight ( Fig. 29 I); lateral lobes with posterior angle broadly rounded. Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobe of pronotum; posterior edge of spiracle with small, finger-like projection. Prosternum armed with two thin, widely separated spines (modified basisternum); meso- and metasternum with basisterna approximately triangular, almost vertical.

Wings in both sexes fully developed, surpassing apices of hind femora ( Figs. 29 A-B). Stridulatory apparatus of male well developed; stridulatory file (vein AA 1) weakly sinusoid ( Figs. 51 E-F), broad, lamelliform teeth; stridulatory area of both wings with no secondary venation; mirror of right wing slightly longer than high, with weak veinlet closely parallel to AA 1. Posterior margin of front wing straight or weakly concave; apex of front wing narrowly rounded.

Legs.— Fore coxa with an elongate, forward projecting spine dorsally; middle and hind coxa with ventral spinelike lobes on posterior margins; all trochanters unarmed. All femora unarmed dorsally but armed ventrally on both margins (sometimes posterior ventral margin of fore femur unarmed); genicular lobes of all femora armed with short spines, outer (anterior) spine usually slightly longer than inner (posterior) one; spines on fore femur usually less developed. Front tibia unarmed dorsally, both ventral margins with immovable spines as long as diameter of tibia. Tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area moderately swollen, with pair of small pits below tympanal slits; middle tibia unarmed dorsally, ventrally armed on both margins; 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 strongly sclerotized, convex and smooth, devoid of hairs except for its apical portion between and on shallow, horizontal lobes formed by hind margin of tergite ( Figs. 29 D-G). Female 10th tergite with deep furrow along midline, narrowly incised apically. Supraanal plate small, rounded, completely hidden under 10th tergite; male cercus unarmed, cylindrical except for apical portion laterally flattened and somewhat dorso-ventrally expanded; female cercus, simple, narrowly conical. Subgenital plate of male with a pair of styli and shallow apical emargination; female subgenital plate small, with hind margin straight or with shallow emargination.

Epiphallus with a pair of sclerotized, blunt convexities, covered by the phallic membrane but without well developed, strongly sclerotized titillators ( Fig. 29 H). Ovipositor long and narrow, straight or weakly curved in apical third, narrowed in basal part; both dorsal and ventral margins of ovipositor smooth; apex of upper valvula rounded; ovipositor shorter or considerably longer than hind femur.

Coloration.— General coloration green; frons green, clypeus and labrum purple (yellow in poorly preserved specimens) antennal articles yellow with posterior edges black resulting in “annulated” appearance of antennae. Thorax uniformly green; legs green but often tympanal area of fore tibia or entire dorsal surface of fore tibia black. Tegmina green with numerous, small, dark brown or black spots; stridulatory area on male wings brown; hind wings transparent but with brightly emerald-green venation (often fades in poorly preserved specimens). Abdominal terga pale emerald-green, sometimes with brown midline on first 4-5 terga, 10th tergite of male brownish-orange; abdominal sterna and pleural membranes purple in well preserved specimens. Dried specimens in entomological collections usually turn yellowish-green in time.

Etymology.— The generic epithet is derived from a combination of Latin words Pluvia (rain) and Silva (forest) to indicate the preferred habitat of at least one species of the new genus.

Remarks.— The two species described below are very similar and males can only be distinguished by the characteristics of the stridulatory file. However, the combination of strong differences between the size of the ovipositor in females of the two species, combined with the differences in the structure of the stridulatory file and minor differences in male genitalia, indicates the presence of two distinct species. Unfortunately, no sound recordings are available for the new species, as it is likely that their availability would confirm the separate status of the two populations.

Only one of the two species, P. levis , is known from Costa Rica. It seems appropriate, however, to provide descriptions of both known species of the new genus within one publication.

Virtually nothing is known about the biology of the new taxa. All specimens of P. levis sp. n. were collected in lowland tropical rainforest of Costa Rica and all of them were collected by either canopy fogging or from freshly felled trees. The rarity of these insects in entomological collection further suggests their exclusively arboreal lifestyle.

The two new species of Pluviasilva bear several similarities to species of the genus Moncheca Walker. The shared characters include a highly sclerotized and strongly convex 10th tergite in male, which is devoid of hairs, except for their small concentration on the posterior edge of the tergite ( Fig. 28 D). The male cercus in both genera lacks inner armature and displays generally similar shape, with laterally flattened and dorso-ventrally expanded apex. In addition, both genera share a rather unique for the family glossy appearance of the cuticle.

The differences between the two genera include the shape of fastigium of vertex (narrow, almost lamelliform in Pluviasilva , wider than scapus in Moncheca ), the structure of prosternum (armed with two spines in Pluviasilva , unarmed in Moncheca ), and the structure of stridulatory apparatus (both left and right mirrors membranous, without secondary veinlets in Pluviasilva , left mirror with secondary veinlets in Moncheca ). The fact that Pluviasilva spp. have a narrow fastigium may also indicate their relatedness to taxa traditionally placed in the subfamily Agraeciini . However, as I mentioned earlier, the status of this subfamily is uncertain, since there is not enough evidence to support its monophyly, nor is the subfamily diagnosable ( Nickle and Naskrecki 1997). For these reasons Pluviasilva is placed tentatively in Conocephalinae s.l.

Unique, apomorphic character states of the new genus are as follows: (1) epiphallus with a pair of sclerotized, blunt convexities, covered by the phallic membrane; (2) male cercus unarmed, with the apex laterally flattened, downcurved, with two small, apical lobes; (3) male 10th tergite strongly sclerotized and convex, with its posterior portion expanded into shallow, horizontal lobes; (4) cuticle (including tegmina) very smooth, glossy; (5) venation of the hind wings emerald-green.

Figures

FIG. 28. Vestria punctata. A. female - habitus, B. female face, C. female head and pronotum, dorsal view, D. male cerci, dorsal and ventral views, E. titillators, posterior view.

FIG. 29. Species of Pluviasilva. A, C, F-J. P. levis: A. male - habitus, C. ovipositor, F. male cerci, lateral view, G. male cerci, dorsal view, H. titillators, I. male head and pronotum, dorsal view, J. male face; B, D-E. P. mexicana: B. male - habitus, D. male cerci, lateral view, E. male cerci, dorsal view.

FIG. 49. Stridulatory files of species of Erioloides. A. E. longipennis, B. ditto, variation, C. E. macrocephalus, D. E. brevipennis, E. E. latiscobinus, F. E. consobrinus.

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.