Bioacoustics of Magnacrus taynguyenensis

Diagnosis. Females can be distinguished from M. tongmianensis by the following: (1) metatarsus IV of M. taynguyenensis has only a weakly developed scopula which is almost restricted in the ventral apical part and undivided ( Fig. 13A ), whereas in M. tongmianensis , scopula on met. IV is relatively well developed, covers about distal half of the ventral surface of met. IV and divided (fig. 2H in Zhu et al. 2002 and fig. 2F in Zhu & Zhang 2008 ); (2) stridulatory spines on the prolateral palp coxa ( Fig. 7E ) in M. taynguyenensis are reduced in number (10 spines), compared to M. tongmianensis (17 spines; Fig. 1E ); (3) the long soft setae on retrolateral surface of tibia IV ( Fig. 7C ) in the M. taynguyenensis is relatively sparse, whereas those setae are rather dense, forming a brush-like structure in the M. tongmianensis ( Fig. 1C ); (4) the notch in the middle of the undivided spermatheca ( Fig. 7D ) in the M. taynguyenensis is relatively deeper than those in the M. tongmianensis ( Fig. 1D ). In males, M. taynguyenensis can be distinguished from M. tongmianensis by the following: (1) M. taynguyenensis has five main keels (PS, PA, PI, SA, A) on the palpal bulb, without distinct VTM ( Fig. 6A–F ), whereas in M. tongmianensis with 7 keels (PS, PA, PSA, PI, RB, A, SA) and a distinct VTM are presented ( Fig. 3A–F ); (2) M. taynguyenensis is spineless on the ventral apical part of tibia I ( Fig. 5D ), different to M. tongmianensis , which has two spines there ( Fig. 2D ); (3) ERF in M. taynguyenensis is clearly above 40 ( Fig. 6F ), significantly higher than the ERF in M. tongmianensis (ERF is ca. 33) ( Fig. 3F ).