Siamgryllacris, Ingrisch, 2018

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 : 238

Siamgryllacris gen. nov.

Type species: Siamgryllacris rufa sp. nov.

Diagnosis. The new genus is similar to Phryganogryllacris but less slender, of stouter appearance. It differs from the latter genus by the male abdominal appendages do not arise from from the latero-apical margins of the ninth abdominal tergite but as medial appendages of the tenth abdominal tergite. This tergite is interrupted in middle and at the median ends prolonged into a projecting, basically compressed appendage, globularly widening at tip and with a compressed medial rim ( Figs. 86 A–E). Both rims together forming a pliers-shaped apparatus while in Phryganogryllacris the appendages of the ninth tergite terminate into outward curved spines.

Siamgryllacris is probably related to Dialarnaca , with which it shares a short obtuse lobe in middle of the apical margin of the globular male ninth abdominal tergite that is followed ventrally by a shallow groove. The abdominal appendages come from tenth abdominal tergite in both genera. But in the new genus that tergite is widely divided in middle with the medial margins carrying a together pincers-shaped projection while in Dialarnaca that tergite is undivided and provided with a pair of upcurved spine-like projections.

Females of Siamgryllacris differ from Dialarnaca , Phryganogryllacris and other genera of Gryllacridinae by the possession of a projection from sixth abdominal sternite instead of only from seventh sternite. The ovipositor is elongate and straight but stouter than in Phryganogryllacris and without the upcurved tip as in Dialarnaca (a female of this genus has only been described for D. longicerca Shi & Bian, 2016 ).

Description. Tegmen with free media anterior; cubitus anterior is single-branched at base, when it divides, the anterior branch approaches MA in a curvature or fully fuses with it for a short distance, after it deviated or divided it divides again into MP and CuA1, rarely MP arises from MA and CuA remains undivided. Male eighth abdominal tergite little prolonged, unmodified. Ninth abdominal tergite in centre, where it starts to become down-curved, with a short granular lobe; below that lobe tergite wide shallowly grooved and with a medial furrow. Tenth abdominal tergite distinct, band-shaped but interrupted in middle; at both sides of interruption with a basically compressed appendage swollen at tip and with a compressed medial rim. Male subgenital plate about as wide as long with wide subtruncate medial lobe; styli thin and short, inserted laterally, little surpassing tip of medial lobe. Female sixth abdominal sternite with a narrow, rounded medial projection overlapping base of seventh sternite; seventh sternite with basal margin little excised in middle forming a membranous pit between sixth and seventh sternite. Female subgenital plate distinctly sclerotised, bowed from left to right. Ovipositor substraight, without apical modification.

Figures

FIGURE 86. Siamgryllacris rufa gen. nov. & sp. nov.: A–F, male abdominal apex in apical view (A–D), lateral view (E), and ventral view (F); G–K, female end of abdomen with seventh sternite, subgenital plate and base of ovipositor in ventral (G–J) and oblique lateral view (K).—Specimens from Ban Mae Salit holotype (A, F), Samoeng paratype (B), Umphang paratypes (C, H), Doi Phukha paratype (D), Ban Mae Salit paratypes (E, J); Samoeng paratypes (G, I, K), Umphang paratype (H). Abbreviations: 6th sixth abdominal sternite, 7th seventh sternite, 8. eight tergite, 9. ninth tergite, 10. tenth tergite, ce cercus, lo medial lobe of ninth tergite, ph phallus, pr process of tenth tergite, rc rim around cercus base, sg subgenital plate, st stylus.