Bioacoustics of Drepanophyllum irisovi

Description. Male ( holotype ). General appearance ( Fig. 1 ) similar to that of D. corrosifolium Karsch, 1896 but with following pattern: head light brown with slightly lighter (almost yellowish) most part of clypeus and of labrum as well as large area under both rostrum and antennal cavities, with brown scape and border of antennal cavity as well as most part of maxillary palpus and spots on head dorsum, with dark brown pedicel and partly antennal flagellum as well as spots on greyish eyes, and with rose anterior surface of upper rostral tubercle as well as yellowish ocelli and rest of antennal flagellum; pronotum yellowish with brown to light brown lateral lobes and hind part of disc, and with thin dark brown border around all pronotal edges; legs also yellowish with dark brown coxae and trochanters as well as small basal part of hind femur, with brown distal parts of all femora and proximal parts of all tibiae as well as long distoventral area on hind tibia and lateral marks on all tarsi, and with almost light brown rest of tibiae and of tarsi; tegmina uniformly brown with yellowish to rose most part of venation ( Fig. 1 ), large yellowish spot on stridulatory apparatus of left tegmen ( Fig. 3 ), contrasting colouration of such apparatus in right tegmen (its venation yellowish, but membranes dark brown; Fig. 4 ), and without any transparent or semitransparent spots and areas on lateral field ( Fig. 1 ); hind wings transparent with brown apical part and light brown to rose venation in rest part ( Fig. 1 ); pterothorax brown to light brown with reddish brown dorsal part; abdomen yellowish to light brown with brown areas on apical and subapical tergites as well as on all sternites, and with dark brown cerci and genital plate as well as distal part of epiproct ( Fig. 5 ). Upper rostral tubercle rather high; its narrow and vertically truncated anterior part (having thin anteromedian groove) about 0.8 mm in height, with almost straight anterior edge in profile, and separated from strongly reduced lower rostral tubercle by moderately narrow concave area (width of this area between antennal cavities almost 0.5 mm ). Tegmina moderately wide, with most widened part of tegmen located not far from tegminal apex and with costal area in distal half of tegmen rather narrow (width of tegmen in point of RS bifurcation ~ 8 mm and in most widened place ~ 10.5 mm ; length of tegminal part before latter place ~ 30 mm and after it ~ 7 mm ); stridulatory apparatus as in Figs 3, 4 ; stridulatory vein of left tegmen rather wide, with 78 or 79 rather long stridulatory teeth (six medial teeth located more sparse and forming distinctly curved part of this vein; Fig. 6 ), and with 27 teeth in 1 mm of middle part of this vein. Last abdominal tergite with slightly concave posteromedian edge; epiproct moderately short but rather wide, almost rectangular (widely truncated at apex; Fig. 5 ); cercus very short and thick, arcuate (moderately curved medially) and with acute and almost spine-like apical hook ( Fig. 5 ); genital plate approximately 1.5 times as long as cercus, elongate, slightly narrowing from basal part to distal third and with more narrowed distal part having small (narrow) but rather deep notch at apex ( Fig. 5 ); genitalia membranous. Variability. Second male ( paratype ) with light brown area under rostrum and antennae, rose tinge on clypeus, brown spot at base of labrum, and completely light brown subapical abdominal tergite, but without reddish tinge on dorsal part of pterothorax. Female. Colouration and strucrture of body distinguished from those of males of this species by following characters: head as in holotype but with a pair of small rose marks under antennal cavities; pronotum with lighter (almost yellowish) band on each lateral lobe along dark ventral border; legs also with lighter (light brown with brown marks) coxae and trochanters; tegmina spotted, with some rather large spots greyish (semitransparent) and lacking venation (row of such spots in costal area, large group of similar spots along anal tegminal edge near point of RS bifurcation, and also similar but smaller and more distal spots scattered between branches of R), as well as with larger reddish spot in proximal part of costal area ( Fig. 2 ); rest of body with yellowish to light brown pterothorax, light brown to brown abdominal sternites, brown to dark brown three last abdominal tergites and epiproct as well as genital plate and ovipositor, and dark brown cerci ( Fig. 7 ); dorsal tegminal fields lacking stridulatory apparatus; last abdominal tergite with semimembranous posteromedian part having almost straight posterior edge; epiproct similar to that of male but with posteromedian part having short and roundly angular projection; genital plate as in Fig. 8 and partly compressed laterally ( Fig. 7 ). Strongly reduced ovipositor with a few small denticles in apical parts of dorsal and ventral valves ( Fig. 7 ). Length (in mm). Body: male 22–23, female 24; body with wings: male 48–50, female 49; pronotum: male 4.9–5.1, female 4.4; tegmina: male 37–38.5, female 36; hind femora: male 28–29, female 29; ovipositor (from base to apex) 2.6. Comparison. fflis species is most similar in colouration and tegminal shape to D. corrosifolium described from another region of Cameroon , but it is distinguished from the latter species by distinctly shorter and thicker male cerci (compare Figs 5 and 14 ), as well as by the absence of any transparent and semitransparent areas and spots in the male tegminal lateral field (the male syntype of D. corrosifolium has a few such spots; see its photograph in Cigliano et al. [2022] ). From D. marmoratum Karsch, 1890 also described from Cameroon , the new species differs in the male tegminal lateral field lacking any distinct semitransparent or transparent areas, and in the tegmina of both sexes narrower and with the most widened tegminal part located distinctly less far from the tegminal apex: the ratios of tegminal length to tegminal width in the point of RS bifurcation and in the widest part are 4.7–5.2 and 3.5–3.7 for D. irisovi sp. n. but 4–4.3 and 2.8–3.3 for D. marmoratum , respectively; the ratios of tegminal length to distance between the widest tegminal part and the tegminal apex are 5.2–5.7 for D. irisovi sp. n. and 3.4–3.8 for D. marmoratum ( D. marmoratum has been measured after photographs in Cigliano et al. [2022] , including those for the female holotypes of this species and of its synonym Karschia corrosa Brunner-Wattenwyl, 1891 ; the latter female is in accordance to all species characters of D. marmoratum ); additionally, the new species is distinguished from D. marmoratum by the femoral colouration yellowish with darkened apical parts (vs this colouration is more or less uniformly brown), the costal and interradial tegminal areas in the point of RS bifurcation much narrower ( Figs 2, 12 ), and the male cerci less strongly curved ( Figs 5, 13 ). From the third species of this genus ( D. furcatum Ragge, 1962 , Uganda ) the new species clearly differs in a very different (not almost uniformly greenish) colouration and another structure of the tegminal stridulatory apparatus (mirror and thickened chord in the right tegmen are distinctly shorter).