Bioacoustics of Obolopteryx nigra

Diagnosis. At first sight, this species resembles O. castanea (Rehn & Hebard, 1914) . It may be separated from O. castanea by the very dark-brown-black color on dorsum (head, antennae, pronotum, abdomen, and legs) ( Figs. 33–34 , 43–44 , 48–49 ). Fastigium of vertex distally more acute and produced (Fig. 35a vs. 19a). Fastigium frontalis (Fig. 35b vs. 19b) compressed, more so distally, in O. castanea it is broader and sub-conical. Pronotum and tegmina ( Fig. 34 vs. 18) slightly shorter, average 3.1 (2.7–3.4) and 2.7 (2.6–2.9), respectively vs . O. castanea average 3.9 (3.1–4.8) and 3.4 (2.9–3.8), respectively. Stridulatory file ( Fig. 36 vs. 20) of different shape and size, in O. nigra n. sp ., the length of the stridulatory file is 7.9 mm , with ca . 150 teeth and 19 teeth mm (9–34); the length of analogous structure in O. castanea is 8.3 mm , ca. 147 teeth and 18 teeth mm (8–35). Tenth abdominal tergite’s membranous projection posterior margin deep V–shape forming two broad lobes, epiproct broadly excised distally (Fig. 38); these characters are not so in O. castanea (Fig. 22). Cerci ( Figs. 37 , 39–40 vs. 21, 23–24) with dorsal thumb more robust and not angulated, i.e. , almost adjacent to the shaft, in dorsal view, the ventral shaft broader proximally and more produced distally. Subgenital plate ( Fig. 40 vs. 24) excised shallow U-shape distally, lateral angles posterior margin slightly truncated about mid portion, less produced and more robust than in O. castanea . Internal genitalia as shown in Figs. 41– 42 vs. 25–26. Females may be separated by the shorter pronotum, average 3.6 mm (3.4–3.7) vs . 4.8 mm (4.0–5.3) in O. castanea ( Fig. 44 vs . 27). Ovipositor less produced, average length 6.2 mm (5.3–6.8), unlike 7.9 mm (7.5–8.1) in O castanea (Fig. 45 vs. 28). The inter-tegmina space is smaller, 0.8 mm (0.7–1.0) vs. 1.3 mm (1.1–1.4) in O. castanea ( Fig. 44 vs . 27). Subgenital plate represented by two robust sub– rectangular structures, each with broad external distal angle, basal sclerites broad sub-rectangular with a moderate protuberance projected towards the ovipositor’s lobe. This set of characters are no so in O. castanea (Figs. 45–47 vs. 28–30).