Bioacoustics of Conocephalus

Remarks: This subgenus is similar to Conocephalus s. str. (the genus Conocephalus is divided into several subgenera by some previous authors, but many of them are possibly only groups of the same subgenus, as they are very similar to each other) in: the shape of the head rostrum in profile (with dorsal and ventral rostral tubercles closely contacting with each other; Figs 11, 15 ); the disposition of spines on the legs; and the structure of the stridulatory apparatus in the male ( Figs 12, 13, 16–18, 20, 21, 23, 27 ) and the abdominal apex in both sexes (including the same type of male genital sclerites; Figs 32, 35, 37, 42, 55 ). But its representatives differ from the majority of species of Conocephalus s. str. in the characters connected with their specialized stick-like appearance (strong adaptation to life on thin stems and very narrow leaves of grasses): body thin; head very long and with very narrow rostrum; proximal antennal segments thickened ( Fig. 12 ), pronotum low and without distinct humeral notches (in typical species of Conocephalus , it is high and with distinct humeral notches; for comparison see Figs 11, 14, 15, 19, 22 and 26, 28 ); fore and middle legs short; hind femora thin. In some species of Megalotheca the male cerci are very different in shape to those of Conocephalus s. str. (for comparison see Figs 43, 46, 50 and 53, 54, 56 ). However, in the other species of this subgenus the male cerci are similar to those of Conocephalus s. str. ( Figs 30, 33, 36, 38 ) or are intermediate ( Fig. 39 ). Also, some species of Conocephalus have the head similar to that of Conocephalus s. str. (their head is shorter and with wider rostrum than in Megalotheca ) and the structure of some other body parts more or less similar to that of Megalotheca (their subgeneric position is unclear; Figs 24, 25 ).

( Figs. 5 , 7 A–B) Description. Male. Body medium for genus. Fastigium verticis narrow, apex blunt, width about 1/3 of scape, with a thin median longitudinal furrow; connected with or slightly apart from frontal verticis. Eyes ovoid, protruding forward and outward. Anterior margin of pronotum slightly arc-shaped, posterior margin rounded; lateral lobe nearly triangular, higher than long, anterior margin with 1 small nick, posterior margin rounded; the area corresponding to thoracic foramen semitransparent, slightly plump; humeral sinus indistinct. Prosternum with a pair of spines. Procoxae with 1 spine; profemora unarmed on ventral surface, apices of genicular lobes with 1–2 spines on inner margin and outer margin unarmed; protibiae with 6 spines on inner margin and 4–7 spines on outer margin of ventral surface; tibial tympana slit-like. Mesofemora unarmed on inner margin of ventral surface, outer margin of ventral surface with 4–5 spines; mesotibiae with 6–7 spines on inner margin and 6–8 spines on outer margin of ventral surface. Postfemora unarmed on inner margin and with 9–12 spines on outer margin of ventral surface, apices of inner and outer genicular lobes with 2 spines separately, dorsal spine long than ventral spine; posttibiae with 24–29 spines on inner margin and 16–23 spines on outer margin of dorsal surface, 1 pair of dorsal apical spurs and 2 pairs of ventral apical spurs. Tegmina long, surpassing apices of postfemora, apices rounded. Stridulatory area of left tegmen trapezoid, Cu2 vein robust, fusiform. Hind wings longer than tegmina. 10 th abdominal tergite broad, posterior margin with a shallow triangular notch, the lateral lobes slightly curved ventrad, apices rounded. Cerci long, slightly incurved, 3/4 basal areas cylindrical, robust, 1/4 apical areas constricted, apices rounded; with two teeth near the middle, the tooth near base short, basal half slightly broad, gradually narrowing, apical half slightly compressed, apex acute, inserted on dorsal surface, directing dorsoinward; the other tooth near apex long, spine-shaped, inserted on inner surface, apex thin and acute, directing ventrad. Subgenital plate roughly rectangular, the middle of posterior margin with a shallow triangular notch. Styli slightly short, cylindrical, apices rounded, inserted on apices of the lobes of subgenital plate. Coloration. Body green. Dorsal surface of head with a broad longitudinal brown stripe, the midline with a thin light stripe. Disc of pronotum with a broad longitudinal blackish brown stripe, outer margins with a light yellow stripe separately, and the midline with a thin light stripe. Dorsal surface of abdomen reddish brown, outer margins with a longitudinal light yellow stripe separately. Spines on ventral surface of mesofemora and postfemora, and spines on dorsal surface of posttibiae brown. Apical areas of two teeth on cercus brown. Costal area of tegmen light, Sc vein light yellow, the other areas light brown. Female. Appearance is similar to male. 10 th abdominal tergite short, the middle of posterior margin with a nearly triangular concavity; epiproct tongue-shaped. Cerci long, conical. Ovipositor straight, basal area slightly narrow, middle area broad, gradually narrowing; dorsal and ventral margins smooth, dorsal valvulae longer than ventral ones, apices of dorsal valvulae blunt while ventral ones acute. Subgenital plate roughly triangular, basal area broad, narrowing, posterior margin straight. Ovipositor yellowish brown.

( Figs. 6 , 7 C–D) Description. Male. Body medium-sized for genus. Fastigium verticis slightly narrow, apex blunt, width about 1/2 of scape; in frontal view, lateral margins paralleled, ventral margin connected with frontal verticis. Eyes subsphaeroidal, protruding forward and outward. Anterior margin of pronotum straight, posterior margin rounded; lateral lobe nearly triangular, higher than deep, anterior margin arc-shaped, posterior margin nearly straight, oblique; the area corresponding to thoracic foramen semitransparent, small, slightly tumid; humeral sinus absent. Prosternum with a pair of spines. Procoxae with 1 spine; profemora unarmed on ventral surface, apices of genicular lobes with 1 spine on inner margin and outer margin unarmed; protibiae with 6 spines on inner and outer margins of ventral surface separately; tibial tympana slit-like. Mesofemora unarmed on inner margin of ventral surface, outer margin of ventral surface with 0–2 spines; mesotibiae with 6 spines on inner and outer margins of ventral surface separately. Postfemora with 0–1 spine on inner margin and 6–8 spines on outer margin of ventral surface, apices of inner and outer genicular lobes with 2 spines separately, dorsal spine long than ventral spine; posttibiae with 22–30 spines on inner and outer margins of dorsal surface separately, with 2 pairs of ventral apical spurs, without dorsal apical spurs. Tegmina not reaching apex of abdomen, apices slightly rounded. Stridulatory area of left tegmen trapezoid, Cu2 vein robust, cylindrical. Hind wings slightly longer than tegmina. 10 th abdominal tergite elongated, basal half broad, apical half narrowing, near apex split, lateral lobes rectangular, curved ventrad. Cerci long, roughly cylindrical, apical areas conical, apices blunt; with two inner teeth near the middle, and bases of two teeth far apart; the tooth near base short, slightly compressed, apex acute, directing inward; the other tooth near the middle conical, robust, apical half slightly compressed, hook-like, apex slightly acute, curved ventrad. Subgenital plate rectangular, the midline of basal half with a shallow longitudinal groove, posterior margin with a V-shaped notch. Styli cylindrical, apices rounded, inserted on apices of posterior margin of the lobes of subgenital plate. Coloration. Body yellowish green (green when alive). Dorsal surface of head with a broad longitudinal reddish brown stripe. Disc of pronotum with a broad reddish brown stripe, outer margins with a light stripe separately, which blue when alive. Apices of postfemora, spines of posttibiae on dorsal surface brown. Middle area of dorsal surface of 10 th abdominal tergite blackish brown. Dorsal surface of apical half of cercus and two inner teeth brown. Costal and subcostal areas of tegmen light, the other areas brown. Female. Appearance is similar to male. Posttibiae with 1 apical spur on outer margin of dorsal surface and 2 pairs of ventral apical spurs. Tegmina reaching end of abdomen. 10 th abdominal tergite short, the middle of posterior margin split, the lobes curved ventrad. Cerci long, conical. Ovipositor rather long, narrow, moderately curved dorsad, basal area slightly narrow; dorsal and ventral margins smooth, dorsal valvulae longer than ventral ones, apices of dorsal and ventral valvulae acute. Subgenital plate broad, posterior margin rounded. Ovipositor light brown.

Description (male except where specified) Head.— Fastigium of vertex 0.75 to 1.5 times as wide as scapus ( Figs. 1 C-E), laterally compressed, rounded dorsally and apically, never hook- or cone-shaped, never projecting strongly in front of eyes; fastigium of vertex touching fastigium of frons. Eyes large relative to size of head, weakly protruding. Frons weakly convex, smooth; tegumen of head smooth, without traces of genal carinae; face slender. Mandibles and labrum symmetrical. Thorax and wings.— Dorsal surface of pronotum smooth, flat or metazona slightly raised; anterior dorsal margin straight, posterior one straight or weakly convex; lateral lobes approximately triangular, with acute posterior angle; posterior edge of lateral lobe with “secondary tympanum” – a somewhat raised, narrowly elliptical area of thinner cuticle covering thoracic auditory spiracle; humeral sinus poorly developed or absent ( Fig. 1 A). Thoracic auditory spiracle large, elliptical, completely hidden under lateral lobe of pronotum; posterior edge of spiracle unmodified. Prosternum unarmed or armed with two thin, short spines (modified basisternum); meso- and metasternum with lateral lobes of basisterna small, triangular, their inner margins touching; posterior part of metasternum strongly compressed causing hind coxa to nearly touch each other. Wings in both sexes either fully developed, well surpassing apices of hind femora , with hind wings usually distinctly longer than tegmina; or wings shortened, barely reaching apex of abdomen; or wings shortened not reaching apex of abdomen; or wings very short, not reaching middle of abdomen, squamipterous in females; often intermediate forms occur, and many species have both macro- and brachypterous forms; in macropterous forms tegmina slender, narrowly rounded apically ( Fig. 2 A). Stridulatory apparatus of male well developed; stridulatory area of left wing membranous, without a network of secondary veinlets; stridulatory file (vein AA 1 —new vein homology after Kukalova-Peck, personal communication; male stridulatory file used to be homologized with the vein Cu 2) sinusoidal ( Figs. 1 B-F), teeth thick, peglike, sparsely arranged, especially on distal end of file; mirror of right wing approximately rectangular, with secondary veinlet next to AA 1 always well developed, divergent from AA 1 . Legs.— All legs long and slender; fore coxa with an elongate, forward projecting spine dorsally. All femora unarmed dorsally; fore and mid femora unarmed ventrally, hind femora armed ventrally with relatively few minute spines or unarmed; genicular lobes of femora usually armed with short spines, sometimes only inner genicular lobes armed. Fore and mid tibiae unarmed dorsally, both ventral margins with immovable spines as long as 1/4 to 1/2 diameter of tibia; 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. Tympanum on fore tibia bilaterally closed, tympanal slits facing forward, tympanal area weakly to distinctly swollen, with pair of small, elongated pits below tympanal slits. Abdomen.— Dorsal surface of abdominal terga smooth, unmodified. Male 10th tergite usually strongly sclerotized, with narrow apical incision, supraanal plate small, triangular. Male cercus variable but usually with one internal spine, sometimes unarmed or with apex of cercus modified into spine ( Figs. 39 A-H); female cercus, simple, slender and weakly incurved. Subgenital plate of male with a pair of styli, distinct median keel, truncated apically or with triangular apical emargination; female subgenital plate approximately triangular, rounded or shallowly emarginated apically. Concealed genitalia of male with paired, heavily sclerotized, hook-like titillators ( Figs.2 G-K). Ovipositor narrow, straight to weakly curved; its length variable, from distinctly shorter to over twice as long as hind femur; both dorsal and ventral margins of ovipositor smooth, parallel; apex of upper valvula sharp ( Figs.2 B-F). Coloration.— General coloration usually green, sometimes straw brown, almost invariably with dark, wide stripe on head and pronotum (stripe black and extending along the dorsal side of the abdomen in nymphs of probably all species); abdomen usually green but often apical half of abdomen colored differently, yellow, orange, red or purple (especially in males); sometimes dorsal side of abdomen yellow, with dark, longitudinal stripes. Tegmina straw brown to light green; legs green to light brown.

Costa Rican fauna of Conocephalus spp. is rather poorly known and requires additional, extensive collecting and studying. At least 5 species occur in this country, including 1 species new to science, described below. With the exception of C. angustifrons , all Costa Rican species seem to be chiefly diurnal. Conocephalus angustifrons is predominantly predaceous and individuals of this species have been observed capturing insects of the size equal to their own, including adult individuals of the predaceous katydid Phlugis sp. Little is known about the diet of the remaining species but they seem to feed on seeds and leaves of various grasses. Males of most species of Conocephalus produce continuous, high duty calls, which can be heard during the day in nearly all open, grassy areas of the country.

Key to species of Conocephalus Thunberg, 1815 1. Fastigium of vertex moderately narrow ( Plate 2 , Fig. 2); hind femur unarmed on ventral side ( Plate 2 , Fig. 16)........... 2 - Fastigium of vertex moderately broad ( Plate 2 , Fig. 6); hind femur armed on ventral side. ( Plate 4 , Fig. 15)............. 3 1. Male cercus with internal tooth present ( Plate 7 , Fig. 8; Plate 5 , Fig. 7).......................................... 4 - Male cercus with internal tooth absent ( Plate 6 , Fig. 13); stridulatory file with 34 teeth; cerci spindle-shaped, apices narrow and slightly rounded.......................................................... Conocephalus nagariensis sp. nov. 1. Stridulatory file with 50 teeth; male cerci thick basally, tapering towards apex; tooth at middle, thick at base, apex with a spine-like projection Plate 2 , Fig. 13)........................................ Conocephalus maculatus (Le Guillou,1841) - Hind femur ventrally unarmed ( Plate 5 , Fig. 16)............................................................. 5 1. Stridulatory file with 36 teeth; subgenital plate flat and longer than broader, basal to apical region uniform, apical margin without any median excision; cerci long, basally narrow and apically thick and broad, apices thick and rounded ( Plate 5 , Fig. 7); internal tooth positioned medially.............................................. Conocephalus usmanii sp. nov. - Stridulatory file with 28 teeth; male subgenital plate elongate, apical margin with a median small V-shaped incision; cerci cylindrical, apices narrow and slightly rounded; internal tooth small at a distal end Plate 7 , Fig. 8).............................................................................................. Conocephalus ganderbali sp. nov. 1. Tegmina ending before the mid of hind tibiae in situ ( Plate 1 , Fig. C); stridulatory file with 34 teeth; male internal cercal tooth without a globular apex ( Plate 4 , Fig. 13)................... Conocephalus kwasiphaiensis Nagar & Swaminathan, 2016 - Tegmina reaching mid of hind tibiae in situ Plate 1 , Fig. E); stridulatory file with 65 teeth; male internal cercal tooth with a globular apex ( Plate 3 , Fig. 13)........................................... Conocephalus longipennis (Haan, 1843)