Orthelimaea volsella, Ingrisch, Sigfrid, 2011

Ingrisch, Sigfrid, 2011, New taxa of Elimaeini (Orthoptera: Tettigoniidae: Phaneropterinae) from South East Asia, Zootaxa 2935, pp. 1-25 : 11-12

Orthelimaea volsella sp. n.

Figs. 10 I–L, 11D–F, 12G–K

Holotype (male): Thailand: Nakhon Ratchasima, Pak Chong (western suburbs) [14°40'N, 101°24'E], 14.v.2002, leg. S. Ingrisch, depository: Museum Koenig Bonn ( ZFMK).

Paratypes: Thailand: 1 male, 2 females, same data as holotype (1 female in ZFMK, remainder in CI); 1 female, same locality, 16.x.1990, leg. S. Ingrisch (CI).

Diagnosis. Differs from all related species by the characteristic phallus sclerites, which consist of a pair of elongate and in lateral view sinuate, at base widened and strongly curved sclerites and a small, unpaired, bi-alar sclerite at very base. The stridulatory vein differs from O. leeuwenii by the area of small dense teeth being shorter and from O. kanburi , in which such an area is absent. The epiproct is similar to those of O. leeuwenii and O. bezborodovi but differs from both by the latero-apical angles not projecting and a triangular apico-medial lobe hardly indicated. The male cerci have the swollen basal area longer and narrower than in all three other species.

Description. Fastigium verticis narrow, dorsally furrowed; separated from fastigium frontis by an angular gap. Pronotum narrow; disc with rounded lateral angles; paranota longer than high; humeral sinus present. Tegmen narrow; hind wings projecting. Anterior coxa with minute spinule. Femora with small black spinules on ventral margins, on hind femur rarely only one spinule or unarmed. Anterior femur straight. Anterior tibia with four apical spurs; tibial tympana conchate on both sides.

Male. Tegmen with costal area distinctly widened in about basal third; dorsal area widened in about basal half, afterwards narrow; stridulatory area moderately wide ( Fig. 10 I). Stridulatory file on underside of left tegmen arched, 1.30–1.39 mm long; teeth medium sized, somewhat spaced, in about apical third becoming narrow and gradually smaller towards apex; with 48 teeth, equating 34 teeth per mm ( Fig. 10 K). Mirror on right tegmen with broadly rounded anterior margin; hind margin substraight with rounded lateral corners, 1.29–1.42 mm long, 1.07– 1.13 mm wide; index length: width 1.21–1.25 ( Fig. 10 J). Tenth abdominal tergite with hind margin little concave in middle ( Fig. 11 D). Epiproct angular, running ventrad then apicad, widening and with little projecting apico-lateral corners, substraight in between ( Fig. 11 E). Cerci only in about basal third conical; afterwards compressed and recurved; apex acute ( Fig. 11 F). Subgenital plate elongate with about apical half nearly parallel-sided; less than apical half divided into two little twisted lobes with numerous spinules along internal margins of fissing area ( Fig. 10 L). Phallus lateral lobes with flat apical to latero-ventral expansion; medial lobe with a pair of compressed hyaline plates and a small unpaired basal sclerite; plates with lateral surfaces very finely setose, towards apex few large setae; dorsal margin in lateral view distinctly sinuate, brown and densely denticulate; basal sclerite brown with ventral area laterally compressed dividing dorsally into two laterally curved, dorso-ventrally compressed branches ( Figs. 12 G–I).

Female. Tegmen with costal are in about basal half moderately widened; dorsal area only little widened near base, gradually becoming narrower behind. [Tenth abdominal tergite distorted in specimens at hand]. Epiproct tongue-shaped with short medial furrow. Cerci little curved; apex pointing. Subgenital plate with central area elevated; apex rounded ( Fig. 12 J). Ovipositor short sabre-shaped; margins in about apical half with strong, large teeth ( Fig. 12 K).

Coloration. Green with fine black dots. Antenna with scapus and pedicellus brown; flagellum green, annulated. Vertex and dorsal area of tegmen dark brown, disc of pronotum with red medial band and fine pale lateral lines. Tegmen with indistinct piles of black dots. Females green; tegmen with brown dorsal band less distinct than in male.

Measurements (2 males, 2 females). Body w/wings: male 30, female 32–37; body w/o wings: male 15, female 18–19; pronotum: male 3.7–3.8, female 3.8–4.1; tegmen: male 23–24, female 24.5–28.0; tegmen width: male 4.5– 5.0, female 4.5–5.0; hind femur: male 17.5–18, female 21–23; ovipositor: female 7 mm.

Etymology. The name of the new species refers to the shape of the phallus sclerites and is derived from volsella Lat. = pliers; noun in apposition.

Stridulation ( Fig. 13 ). A single isolated male was recorded. It produced, at night and 23°C, only five chirps in 45 minutes continuous recording. One chirp lasted between two and four seconds (mean 3.112 s), with short crescendo at start and of equal loudness thereafter. The frequency peak within the audible range was around 14 kHz but it is supposed to contain ultrasonic components. The pauses between the chirps lasted between 7 and 10 minutes, but there was a long period of silence at the end of the recording.

Figures

FIGURE 10. Stridulatory area of left (A, E, I) and right male tegmen (B, F, J); stridulatory file on underside of left tegmen (C, G, K); male subgenital plate (D [without base], H, L). A – D, Orthelimaea leeuwenii (Karny, 1926) syntype in RMNH; E – H, O. kanburi sp. n. paratype; I – L, O. volsella sp. n. paratype.

FIGURE 11. Male abdominal apex in lateral view (A, D); same in dorsal view (B, E); male cercus (C, F); apical area of cercus (G). A – C, Orthelimaea kanburi sp. n. paratypes; D – F, O. volsella sp. n. [D – E, holotype; F, paratype]; G, O. leeuwenii (Karny, 1926) syntype in RMNH. Abbreviations: 10 t, tenth abdominal tergite; c, cercus; e, epiproct.

FIGURE 12. Male phallus with sclerites in dorsal view (A, B, G); phallic sclerites in lateral view (C, H); same in dorsal view (D); same in view from base (I); female subgenital plate (E, J); female apex of abdomen with ovipositor (F, K). A, Orthelimaea leeuwenii (Karny, 1926) syntype in RMNH; B – F, O. kanburi sp. n. [B, D, paratype males; C, holotype; E – F, paratype female]; G – K, O. volsella sp. n. [G, paratype male; H – I, holotype male; J – K, paratype female]. Scales = 1 mm.

FIGURE 13. Stridulation of Orthelimaea volsella sp. n. at 23 ° C in darkness.