Bioacoustics of Nesoecia huichihuayan

Diagnosis. N. huichihuayan n. sp. , may be compared with N. nigrispina Stål (see Cigliano et al., 2020 ; http://orthoptera.speciesfile.org/Common/basic/ShowAllImages.aspx). It may be distinguished of the latter species by its larger size ( 37 mm males, 45 mm females vs. 34 and 35 mm N. nigrispina male and female, respectively; see Brunner von Wattenwyl, 1895 ; Cigliano et al., 2020 ) ( Figs. 1 , 13a ; 14 ). Tegmina ( Figs. 1 , 13a , 14 ) are slightly more elongated ( 8.3 mm males and 8.7 mm females vs. 7 mm in male and 8.0 mm in female N. nigrispina ); in females tegmina are broader and the distal apex does not overlap. In males, the stridulatory apparatus is of different shape and larger size ( Figs. 6-7 ); the cerci are shorter and proximally broader, tapering gradually, distally curved inwards, and bear a more acuminate apex spine ( Figs. 9-11 ); the subgenital plate ( Fig. 11 ) is distally more produced and the styli proximally broader than in N. nigrispina . In females, the ovipositor is longer (18.8 vs. 15 mm ) ( Figs. 14, 24 ), the pronotum larger (10.5 vs ., 10.0 mm in N. nigrispina ), more coarsely granulated, and the posterior margin not conspicuously truncate ( Figs. 14, 17-18 ); tegmina broadly ovate, in dorsal view, the distal apex does not overlap ( Figs. 14, 20 ). These set of characters are not so in N. nigrispina (see Cigliano et al., 2020 ; http://orthoptera.speciesfile.org/ Common/ basic/ Show AllImages. aspx). Male description alive ( Figs. 1-13 ). General body color dark brown ( Figs. 1 , 13 ), head pronotum and tegmina almost black. Fastigium of vertex triangular, broadly pointed, deep and broadly sulcate along midline, scarcely surpassing the antennal scrobes; fastigium frontalis broad sub-triangular, apex broadly rounded ( Figs. 2a, 2b ). Pronotum ( Figs. 1, 3, 4 , 13a) three sulcate, coarsely granulated, declivent from anterior towards mid-portion, with large black marks typical of the genus, anterior margin rounded strongly emarginated bearing a medium size tubercle on mid portion, posterior margin emarginated and slightly truncate about mid length. Lateral lobes of pronotum ( Figs. 1, 4 ) wider than deep, lower margin emarginated and truncate about mid-length, anterior angle sub-rectangular, posterior angle obtuse angulate. Pro, meso, and metasternum ( Fig. 5 ) as described for the genus. Legs short, brown-pinkish with dark brown-black ornamentation. Femora spines: anterior inner face lower margin five spines (four large: one small, the small spine proximal to the body); middle external lower margin with three spines (small, medium, and large size, respectively, from proximal to distal portion); posterior external face lower margin six spines (one small, two medium, and three large, from proximal to distal portion). Tibiae spines: anterior external face lower margin seven small reddish-brown spines with dark tip, inner face seven spines on lower margin, size medium to small from proximal to distal portion; middle external and internal face each with seven small spines on lower margin; posterior external face three crème color spines with dark tip on upper margin, and 10 smaller reddish-brown spines on lower margin, inner face nine small spines on upper margin and seven smaller on lower margin. Tegmina ( Figs. 1 , 7 , 13a) abbreviated not surpassing the posterior margin of the second abdominal segment, mostly dark brown-blackish, broadly ovate, densely reticulated, crème veinlets; stridulatory apparatus ( Fig. 6-7 , 13a) dark brown in alive specimens-yellowish in dead collection specimens; stridulatory file ( Fig. 8 ) length 3.2 mm , average 145 teeth. Cerci as shown in Figs. 9-11 . Subgenital plate ( Fig. 11 ) proximal half broad, then tapering towards the bidentate apex, each teeth bearing a robust style. Internal genitalia as shown in Fig. 12 . Female description alive ( Figs. 14-25 ). In general appearance similar to the male but larger size ( Fig. 14 ). Head dark brown-black color, fastigium of vertex triangular, distally produced weakly V-shape emarginated, surpassing slightly the antennal scrobes ( Fig. 15 ), fastigium frontalis ( Fig. 16 ) sub-triangular, apex broadly rounded. Pronotum ( Figs. 14, 17-18 , 25) similar to the male, less densely granulated, anterior margin rounded emarginated and slightly produced, posterior margin emarginated not conspicuously truncate; lateral lobes ( Figs. 14, 18 ) wider than deep, pro, meso, and metasternum as shown in Fig. 19 . Supraanal plate and cerci as shown in Figs. 21-22 . Subgenital plate ( Figs. 22-23 ) sub-triangular, proximally broad, then tapering gradually towards the shallow V-shape emarginated apex forming two broad lobes. Ovipositor as in Figs. 24 .

Etymology. Specific epithet refers to the type Locality “Huichihuayán”, a small and picturesque town located southeast of the state of San Luis Potosí . Acoustic Signal ( Figs. 28-33 ). Males of N. huichihuayan n. sp. , sing day and night. They produce a low frequency audible song made up of two syllables mostly ( Figs. 28 , 31 ). For this species we recorded two rhythms of acoustic signals: a) a very fast signal ( Fig. 28-29 ) emitted at a rate of up to 390 echemes/min ( n = 9 min analysis), this high echeme repetition rate per minute may be achieved because there is no minor interval (MiI) between syllables 1 (S1) and 2 (S2) or major interval (MaI) between echemes. Duration of two-syllable echemes is 160.0 ± SD 11.0 ms (148.0-188.0; n = 32), duration of S1 and S2, respectively, is: 38.0 ± SD 2.2 ms (32.0-41.0; n =25), 124.0 ± 12.0 (107.0-145.0; n =25); b) a low rate song ( Figs. 31-32 ) without minor interval (MiI) emitted at a rate of 128.0 echemes per min ( n =5 min), duration of two-syllable echemes is 277.0 ± 11.2 ms (259-310; n =25), duration of S1 82.4 ± 6.0 ms (73.0-104.0; n =25), and S2 195.2 ± 10.0 ms (175-214; n =25); major interval (MaI) duration 249.0 ± 37.2 ms (204.0-363.0; n =25). In both rhythms of signals the peak fi is 14-26 kHz ( Figs. 29-30 , 32-33 ).