Bioacoustics of Pseudochorthippus turanicus

Description. Head from above shorter than pronotum; face slightly oblique in lateral view ( Figs 2–3, 5–7, 9 ). Foveolae with curved upwards or almost straight parallel margins, 2.5–3.0 times as long as their maximum width ( Fig. 10 ). Vertical diameter of eye 1.5–2.0 times greater than subocular furrow in male ( Fig. 9 ) and 1.4–1.5 times greater than subocular furrow in female. Antennae filiform, 10 th –12 th segments in male, respectively, 2.5–3.1, 2.4–3.3, and 2.4–3.0 times as long as their width in broadest aspect, in female, respectively, 2.0–2.7, 2.2–2.6, and 2.1–2.9 times as long as their width. Anterior margin of prozona rounded; posterior margins of metazona almost straight, projecting backwards at an obtuse angle. Lateral carinae concave in prozona, slightly divergent or almost parallel in back part of metazona. Ratio of maximum/minimum widths of pronotum 1.4–2.0; prozona nearly as long as metazona. Length of lateral lobes of pronotum measured along lateral carina exceeds their maximum width by 1.1–1.3 times in male and by 1.1–1.2 times in female. Mesosternal lobes are 1.5–2.1 times as wide as mesosternal interspace in both sexes, mesosternal interspace trapezoidal ( Fig. 11 ). In brachypterous male, tegmina not reach apices of hind femora, only sometimes almost reach bases of dark-colored distal parts of hind femora, with narrowly rounded apices; hind wings shortened, about half or third shorter than tegmina ( Figs 2–3 ). In brachypterous female, tegmina strongly shortened, only occasionally reach middle of hind femora ( Figs 6–7 ). In macropterous male, tegmina distinctly exceed apices of hind femora, with wider apices; hind wings only slightly shorter than tegmina ( Fig. 5 ). In macropterous female, tegmina reach or only slightly exceed apices of hind femora. Radial vein of tegmen almost straight. Stigma quite often poorly developed ( Fig. 8 ), in macropterous individuals usually absent ( Fig. 5 ). Ratio width of C/Sc areas of tegmen 1.7–2.4 in brachypterous male, 1.8–2.7 in macropterous male, and 2.5–3.0 in macropterous female. Ratio width of C+Sc/R areas of tegmen 1.7–2.3 in brachypterous male, 1.7–2.5 in macropterous male, and 2.1–2.4 in macropterous female. Hind femora in both sexes 4.5–5.8 times longer than their maximum width. In male, stridulatory file consists of 105–134 pegs arranged in single row vs 102–106 in P. geminus and 104–113 in P. parallelus from Kazakhstan ( Tishechkin, 2024 ); according to Reynolds (1980) , maximum number of pegs in European males of P. parallelus reaches 110. Hind tibiae with 10–13 spines both in outer and inner dorsal rows. Arolium almost reaches or even slightly exceeds middles of claws, length of 1 st hind tarsomere equal to length of 3 rd tarsomere without claws. Tympanum wide, oval. Cerci conical, 2.0–2.7 times as long as their width at base ( Fig. 12 ). In shape of male genitalia similar to P. parallelus ( Figs 13–17 ). No differences were found between macropterous and brachypterous forms in any characters other than size and proportions of wings or their parts. In dorsal view, body brown or yellowish brown, usually, with variable irregular dark pattern on head and pronotum, ventrally, lighter, yellowish brown. Hind femora brown with yellowish ventral and inner parts and dark brown or black knees. Hind tibiae yellowish or reddish, darkened distally, dorsal spines with black apices. Externally similar to P. parallelus and P. geminus , but differs from them in larger size, proportions of pronotum, shorter first hind tarsomere, and higher average number of stridulatory pegs in male. Measurements (mm). Length of head in dorsal view: ♂ , 2.5–3.2, ♀ , 3.0–3.5; length of pronotum: ♂ , 3.5–4.3, ♀ , 4.4–5.4; length of tegmina: brachypterous ♂ , 10.3–11.6, macropterous ♂ , 13.3–17.7, brachypterous ♀ , 8.2–11.0, macropterous ♀ , 16.6–17.1; width of tegmina: brachypterous ♂ , 2.7–3.2, macropterous ♂ , 4.1–4.2, macropterous ♀ , 3.9; length of hind femora: ♂ , 10.5–12.1, ♀ , 12.7–14.9; width of hind femora: ♂ , 2.0–2.5, ♀ , 2.3–2.9. Song. The calling song is an echeme lasting from 7–8 to 15–20 s in our recordings ( Figs 18–19 ). The song begins quietly and reaches its maximum intensity near the end; usually only several last syllables have a lower amplitude than the preceding ones. In the songs of different males, the syllable repetition period varies from 190– 200 to 230–260 ms; sometimes it decreases slightly towards the end of the song. Each syllable has several gaps, which are sometimes indistinct or almost entirely absent ( Figs 20–23 ). Song recordings from four localities in southeastern Kazakhstan and one locality in northern Kyrgyzstan were studied ( Fig. 1 ). Songs of males from different localities, as well as songs of macropterous and brachypterous males and songs of males with different numbers of stridulatory pegs, do not have significant differences. In the temporal pattern of the song, P. turanicus is completely different from P. parallelus , which is further evidence that it is a good species (cf. Figs 18–23 and 24–26 ).