Bioacoustics of Hygronemobius indaia

Description. Holotype , male, measurements (mm): BL 8.00; ID 1.02; LP 2.22; WP 1.60; LF 5.63; LT 4.44; TL 3.2; TW 2.37. Head dark yellowish, showing dark brown stripes on apex and forehead, covered with semi erect long black bristles on the median region, presence of fine and short light brown bristles covering all its extension; black eyes; three ocelli present, central ocellus surrounded by dark brown spot, lateral ocelli partially surrounded by one dark brown spot each; antennal scape light yellowish with an irregular dark brownish spot; antennomeres light brownish; gena brownish with a central light yellowish spot; clypeus dark brownish on the superior portion and light brownish on the median and inferior portion; labrum dark brownish with a central light yellowish spot on the superior portion and dark brownish on the inferior portion; mandibles dark brownish; maxillary and labial palpi whitish with truncate apex; last palpomere of each maxillary palpi with one light brownish ring on distal margin that covers the entire ventral surface. Thorax with pronotum dark yellowish adorned with diffuse dark brownish spots, presence of fine and short black bristles covering all its extension; longitudinal midline of pronotum with a light brownish spot close to its anterior margin, a dark yellowish to light brownish drop-shaped spot at each side of the midline, and other two light brownish spots with dark yellowish center, close to the posterior margin of pronotum; latero-inferior lobes dark brownish with four yellowish spots aligned diagonally on anterior portion and some diffuse black bristles; row of long black bristles on anterior and posterior pronotum border. Tegmina ( Fig. 1 D) light brownish with a longitudinal light yellowish stripe covering the veins Cu1 and M, one spot at the junction of Cu2, 1A, 2A and 3A and another at the limit between cordal and apical area. Hindwings absent. Prosternum light yellowish on anterior margin, to light brownish on posterior margin, mesosternum dark brownish on anterior margin, to light yellowish on posterior margin, and metasternum light brownish. Fore and mid legs with similar pattern: coxa and trochanter light yellowish with indistinct light brownish spots; femur light yellowish, with some light brownish spots; tibia with two distinct light brownish rings being separated from each other by a light yellowish area; some strong black bristles recovering femur and tibia surface; fore tibia with tympanum; first tarsomeres with two light brownish rings separated from each other by a light yellowish area, second tarsomeres light brownish and third tarsomeres light yellowish on proximal portion to light brownish on distal margin. Hind femurs light yellowish with light brownish strips on dorsal and outer surface, presence of some black bristles on dorsal and ventral portion; tibia light yellowish with light brownish spots, three inner and three outer dorsal spurs, two inner and three outer apical spurs; first tarsomeres light yellowish with one light brownish ring on distal margin, second tarsomeres with two light brownish rings separated from each other by a light yellowish area, and third tarsomeres light yellowish on proximal portion to light brownish on distal margin. Abdomen with tergites I– IV dark brownish with one light brownish central spot on basal margin, tergites V and VI dark brownish with two semicircular light brownish spots on each side of the midline, tergite VII similar to VI with two stripes on each side of the midline, tergites VIII and IX dark brownish with a little central light brownish spot, tergite X light brownish. Supra-anal plate light brownish, reduced and M-shaped. Sternite I dark brownish on anterior margin to light yellowish on posterior margin, sternites II–VIII dark brownish on lateral thirds to light brownish on center, sternites II–VI with a central light yellowish spot on anterior margin, sternite VIII dark brownish. Subgenital plate dark brownish with all angles rounded. Cerci light yellowish. Male genitalia in paratypes : genitalia with rectangular shape, visible in ventral and dorsal view ( Fig. 2 A,B); pseudepiphallic apical lobes with almost half the length of pseudepiphallic sclerite, visible in dorsal view ( Fig. 2 B); pseudepiphallic apical lobes setaceous, little sclerotized and partially separated by a cleft, visible in ventral and dorsal view ( Fig. 2 A,B); ends of pseudepiphallic apical lobes directed towards ventral side, visible in lateral view ( Fig. 2 C); pseudepiphallic median lobe with invagination, visible in lateral view ( Fig. 2 C); pseudepiphallic sclerite with some setae on lateral margins, visible in dorsal view ( Fig. 2 B). Ectophallic fold curved in a half disc format, visible in lateral view ( Fig. 2 C); Ectophallic apodeme not crossing or surpassing the rami, when in ventral and dorsal view ( Fig. 2 A,B). Endophallus divided in three sclerites, being one central and two lateral ( Fig. 2 A); endophallic central sclerite longer than wide with proximal ends bulged, visible in ventral view ( Fig. 2 A). Female: body shape very similar to male, showing only the following differences: tegmina reduced to lateral scales. Maxillary and labial palpi entirely whitish. Tergite I totally dark brownish; tergites II–VIII with a dorsal portion light yellowish, punctated by short dark brownish spots, anterior margin with a dark brownish narrow stripe, being the lateral portions light brownish; tergite IX light brownish with the center of dorsal portion light yellowish. Supra-anal plate squared, light yellowish and with a light brownish spots. Sternite I light brownish on anterior margin to light yellowish on posterior margin, sternite II– VI light brownish with one light yellowish spot on center and two light yellowish spots at lateral thirds, sternite VII light brownish with two light yellowish spot at lateral thirds and one on posterior margin. Subgenital plate light brownish with two light yellowish spots at posterior margin. Ovipositor with superior valves dark brownish and inferior valves dark yellowish ( Fig. 1 F). Male calling song in paratypes . ( Fig. 5 A): trains of chirps composed of 4, 5 or 6 pulses; chirps with 4 pulses lasted 55.41 ± 1.84 ms (48–57, n=58), 5 pulses 67.49 ± 4.18 ms (62–73, n=83) and 6 pulses 77,42 ± 0.51 ms (77– 78, n=12); the chirps were separated from other chirps by 130.5 ± 30.37 ms (62–249, n=150) in undisturbed bursts of song; each pulse had a duration of 7.36 ± 1.46ms (5–10, n=39) and inter-pulse interval was 7.77 ± 0.93 ms (6–9, n=30); pulse rate of 59–71 pulses/s and chirp rate of 258–342 chirps/min. The frequency amplitude ranged from 4.4 to 6.7 kHz with a dominant frequency between 5.1 and 5.6 kHz.