Asarcogryllacris (Pseudolarnaca) genualis ( Walker, 1869 )

Ingrisch, Sigfrid, 2018, New taxa and records of Gryllacrididae (Orthoptera, Stenopelmatoidea) from South East Asia and New Guinea with a key to the genera, Zootaxa 4510 (1), pp. 1-278 : 125

Asarcogryllacris (Pseudolarnaca) genualis ( Walker, 1869)

Figs. 42 A–G

Material examined. Malaysia: Penang, Island of Penang , leg. Rosenberg— 1 male (Wien NHMW, BrW26384 " G. genualis Walker " det. Karny) . Thailand: Trang, Khao Chong , (7°30'N, 99°50'E), 23.x.1991, leg. S. Ingrisch— 1 female (Bonn ZFMK) .

Description. Small to medium sized species. Head: Face ovoid; forehead nearly smooth, in middle with very fine indistinct transverse riffles; fastigium verticis little wider than scapus; ocelli indistinct; fastigium frontis separated from fastigium verticis by a very fine suture; subocular furrows weak ( Fig. 42E ). Abdominal tergites two and three each with rows of stridulatory pegs (?, 4; 6, 6; n = 1 female).

Wings reaching hind knees ( Fig. 42A ). Tegmen ( Fig. 42D ): Radius with two branches, both forked near tip; media anterior free at very base, then in about basal half fused with radius with fused area markedly thickened, free apical area undivided; cubitus anterior single-branched at base, later forks into two veins; cubitus posterior undivided, free throughout; with 4 anal veins.

Legs: Fore coxa with a spine at fore margin; fore and mid femora unarmed; fore and mid tibiae with four pairs of large ventral spines and one pair of smaller ventral spurs; spines not very long; hind femur with 8–10 external and 9–11 internal spines on ventral margins; hind tibia with spaced spines on both dorsal margins, ventral margins with one pre-apical spine; with 3 apical spurs on both sides.

Coloration. General color brown; vertex with 2 small black spots, pronotum black with a small spot at anterior and a wide spot at posterior margin light brown; legs brown with genicular areas black. Face uniformly brown, only at ventro-internal angle of antennal scrobae with a black spot. Tegmen semi-transparent brownish, towards base darker; veins brown; hind wing semi-transparent white, veins brown to dark brown, cross veins in central area nearly black.

Male. The male differs from A. genualis sensu Gorochov (2005) by the absence of projections from apical area of ninth abdominal tergite, instead the surface is smooth and the ventral apical margin is slightly convex in middle and little concave on both sides ( Fig. 42C ). The tenth abdominal tergite is very narrow, of light color and entire, faint angularly projecting in middle; on its ventral margin there might be a pair of short black projections. But for proofing this with certainty, the specimen has to be relaxed and the subgenital plate opened thus that the hidden part of the abdominal apex can be studied more precisely. Color pattern and venation of tegmen agree with those of the female from Khao Chong. Subgenital plate wider than long; apical margin slightly bilobate; rather short styli inserted at apico-lateral angles ( Fig. 42B ).

Female. Seventh abdominal sternite of normal shape; but intersegmental membrane between seventh sternite and subgenital plate little prolonged and provided with a small, semi-oval sclerite covering base of subgenital plate ( Fig. 42G ). Subgenital plate semi-oval, wider than long. Base of ovipositor normal. Ovipositor moderately long, regularly curved with converging margins; tip subacute ( Fig. 42F ).

Measurements (1 female).—body w/wings: 29; body w/o wings: 24; pronotum: 4.5; tegmen: 19; tegmen width: 6.5; hind femur: 14; antenna: 160; ovipositor: 11 mm.

Discussion. The specimens at hand agree with regard to general habitus, wing length and coloration with descriptions in Griffini (1908c, 1909a), Karny (1928f) or Gorochov (2005). They differ by venation of tegmen in that the cubitus anterior divides into only two branches, not three as described and figured in Karny (1929d). The female from Khao Chong also differs by the shape of the small sclerite arising from the membranous area between the seventh sternite and the female subgenital plate being widest at base, not in apical area as figured in Gorochov 2005 for A. genualis from Java, and narrowing towards tip, which meets a granular zone of the subgenital plate not a faint furrow. The male differs from A. genualis sensu Gorochov (2005) by the ninth abdominal tergite being without a pair of obtuse lobular projections before apical margin but is simply rounded and faintly projecting in middle. The tenth abdominal tergite is band-shaped but broader and more expressed than in the drawing by Gorochov (2005) and carries at ventro-proximal margin a pair of black projections (mostly hidden on the photographs at hand. The holotype of A. (P.) nigroscutata ( Brunner, 1888) from "Batavia" in SMNS Stuttgart (Holstein & Ingrisch 2004) and a male from Penang (BrW26.384) in NHMW agree in this respect and both differ from the specimen reported by Gorochov (2005) from Java, 20–25 km SE Bogor Town, near Cemande Vill., Pangrango Vill. 1000 m. Some variation between specimens from different islands was already noted by Gorochov (2005). But as long as Walkers' type of the species from unknown locality that has never been re-examined since Walkers' description is not found and re-described it is difficult to decide on the taxonomic value of that variation.

Figures

FIGURE 42. Genus Asarcogryllacris subgenus Pseudolarnaca: A–G, A. (P.) genualis (Walker, 1869) male from Brunner's collection (BrW26.384, A–C) and female from Khao Chong (D–G); H–O, A. (P.) cornualis sp. nov. female paratype (H–K), male paratype (L) and male holotype (M–O).—Habitus dorsal view (A, H, L), left tegmen (D), face (E, J), male abdominal apex in apical (B, O), oblique ventro-apical (C), ventral (M) and oblique lateral view (N), female seventh abdominal sternite and subgenital plate (G, I), ovipositor (F, K).